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What Does Drinking Soy Milk Do to Hormone Levels?

The vast majority of breast cancers start out hormone-dependent, where estradiol, the primary human estrogen, “plays a crucial role in their breast cancer development and progression.” That’s one of the reasons why soy food consumption appears so protective against breast cancer: Soy phytoestrogens, like genistein, act as estrogen-blockers and block the binding of estrogens, such as estradiol, to breast cancer cells, as you can see at 0:24 in my video How to Block Breast Cancer’s Estrogen-Producing Enzymes.

Wait a second. The majority of breast cancers occur after menopause when the ovaries have stopped producing estrogen. What’s the point of eating estrogen-blockers if there’s no estrogen to block? It turns out that breast cancer tumors produce their own estrogen from scratch to fuel their own growth.

As you can see at 1:03 in my video, “estrogens may be formed in breast tumors by two pathways, namely the aromatase pathway and sulfatase pathway.” The breast cancer takes cholesterol and produces its own estrogen using either the aromatase enzyme or two hydroxysteroid dehydrogenase enzymes.

So, there are two ways to stop breast cancer. One is to use anti-estrogens—that is, estrogen-blockers—like the soy phytoestrogens or the anti-estrogen drug tamoxifen. “However, another way to block estradiol is by using anti-enzymes” to prevent the breast cancer from making all the estrogen in the first place. And, indeed, there are a variety of anti-aromatase drugs in current use. In fact, inhibiting the estrogen production has been shown to be more effective than just trying to block the effects of the estrogen, “suggesting that the inhibition of estrogen synthesis is clinically very important for the treatment of estrogen-dependent breast cancer.”

It turns out that soy phytoestrogens can do both.

Using ovary cells taken from women undergoing in vitro fertilization, soy phytoestrogens were found to reduce the expression of the aromatase enzyme. What about in breast cancer cells, though? This occurred in breast cancer cells, too, and not only was aromatase activity suppressed, but that of the other estrogen-producing enzyme, as well. But this was in a petri dish. Does soy also suppress estrogen production in people?

Well, as you can see at 2:34 in my video, circulating estrogen levels appear significantly lower in Japanese women than Caucasian American women, and Japan does have the highest per-capita soy food consumption, but you can’t know it’s the soy until you put it to the test. Japanese women were randomized to add soy milk to their diet or not for a few months. Estrogen levels successfully dropped about a quarter in the soy milk supplemented group. Interestingly, as you can see at 3:04 in my video, when the researchers tried the same experiment in men, they got similar results: a significant drop in female hormone levels, with no change in testosterone levels.

These results, though, are in Japanese men and women who were already consuming soy in their baseline diet. So, the study was really just looking at higher versus lower soy intake. What happens if you give soy milk to women in Texas? As you can see at 3:29 in my video, circulating estrogen levels were cut in half. Since increased estrogen levels are “markers for high risk for breast cancer,” the effectiveness of soy in reducing estrogen levels may help explain why Chinese and Japanese women have such low rates of breast cancer. What’s truly remarkable is that estrogen levels stayed down for a month or two even after the subjects stopped drinking soy milk, which suggests you don’t have to consume soy every day to have the cancer protective benefit.

Wait, soy protects against breast cancer? Yes, in study after study after study—and even in women at high risk. Watch my video BRCA Breast Cancer Genes and Soy for the full story.

 What about if you already have breast cancer? In that case, see Is Soy Healthy for Breast Cancer Survivors?

 And what about GMO soy? Get the facts in GMO Soy and Breast Cancer.

 Okay, then, Who Shouldn’t Eat Soy? Watch my video and find out.


What else can we do to decrease breast cancer risk? See:

 You may also be interested in:

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:

Discuss

Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.


58 responses to “What Does Drinking Soy Milk Do to Hormone Levels?

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  1. Dr. Greger:

    I am struggling with something and hoping you can shed some light. I was diagnosed with Stage 3B Triple Negative Breast Cancer in April 2018. In surgery, they found a 30% hormone based cancer as well. It was suggested I take an aromatase inhibitor, which I declined to do so. We survivor are told not to eat soy because it will increase our estrogen levels. However, you and Dr. Weil say the opposite.

    Can you please explain? And which soy based food are best?

    Thank you so much. I hope to hear back.

    Sincerely,
    Jennifer

    1. Jennifer Squires,

      I’m sorry about your diagnosis.

      I was diagnosed with early stage breast cancer 6 years ago, and I did take tamoxifen (not aromatoase inhibitors, as I already have osteoporosis). And I also consume soy products, mostly soy milk and yogurt, tofu, tempeh, miso, and edamame. Maybe 1 or 2 servings a day. In fact, after watching these videos, and doing some additional research, I increased my previously lower soy food intake.

      I suggest you re-read this blog, then watch the videos cited in it and others as well (you can find them using the search function). You can even look at the scientific publications reported in the videos (links are provided under each video). Hopefully, if you provide references to your doctor, you can discuss the evidence with him or her. If not, you can decide what the best course for you is.

      I have found doctors woefully inadequate when it comes to nutrition. In fact, I switched from a vegetarian diet to a whole plant foods diet (dropping eggs and dairy) after I discovered this site — I was researching the effects of nutrition on the course of breast cancer, which runs 100% through my family. And I’m angry that nutrition counseling is not offered as part of breast cancer treatment — though it would be even better to offer it before and diagnosis. And what WAS offered in the oncology clinics is bugwah: polished river stones, meditation, massage, yoga, etc. These may make a patient feel better, but I think a healthier diet can actually make a patient better.

      I wish you all the best.

    2. @Jennifer:

      The more whole soy the better, like with anything else. But Tofu, and soy milk are fine.

      There are alpha and beta estrogen receptors. One of the receptors, I believe it is the beta receptor, is what you don’t want estrogen binding to as you get negative things going on in the body. The phytoestrogens in soy bind to the beta receptor and crowds out estrogens ability to bind to the beta receptor, thus making it so estrogen can’t get some of the processes started that increase cancer risk.

      There are a number of videos on it, here are a couple links. But you can search: “soy beta receptor”, and you will get a list of videos that talk about it. There are more, but searching that term will give you a start.

      https://nutritionfacts.org/video/is-soy-healthy-for-breast-cancer-survivors/
      https://nutritionfacts.org/video/what-are-the-effects-of-the-hops-phytoestrogen-in-beer/
      https://nutritionfacts.org/video/who-shouldnt-eat-soy/

    3. Jennifer, you can get a great explanation about why soy is protective from both Dr. Greger’s videos on soy and from Dr. Kristy Funk, who is a breast cancer surgeon. She has done several interviews where she talks about this. One is at Chrisbeatcancer.com.

    4. Jennifer, I think you will find some answers in the following video. After you watch that why not check out “The Doctor’s Notes” below the video for more recommendations on videos reviewing soy and breast cancer. I think you’ll find some encouraging remarks. Best of health to you.

  2. I have been thinking about soy. I am post-menopausal and was drinking soy milk in my green tea latte, but I am not doing that.

    Once in a while, I eat a package of edamame.

    But I really never do tofu and I haven’t had Miso since my Instapot sprayed it all over my cabinets.

    I wonder how bad it is not to have it post-menopausal or is it more useful for managing menopause.

    Sex Education and Health classes never prepare young women for menopause or post-menopause at all and when my friends have talked to their doctors, the answer seems to be “It varies quite a bit.”

    I guess I have to listen to Dr. Barnard’s hormone book, but post-menopause, I think he recommended the progesterone cream and, if I have not been doing that, I wonder if it would mess things up to start now. (He got me to buy some, but then, I got home and my “home brain” is different than my “Just read something on Dr. Barnard’s Website brain” and I suddenly didn’t feel good about it and there was not a live Q & A.

    Wait, he has a lot of live Q & A’s right now, I just got to get there on time and ask.

  3. I’ve heard the optimal range of soy is 3-5 servings per day, is this true? For men and women? Or about how many mg of isoflavones is best?

    1. John, I don’t have time to look up where I learned this, but I think around 70 mg of isoflavones per day is best. For most soy products, this translates into 2 servings per day.

  4. One of my other thoughts about soy is that the infrared has helped me break off the no-oil hummus. I haven’t had it in days and mentally, when I think of soy, I am afraid that I will just drop one source of fat and take up another, which is what I believe I have done all of this time, and soy milk was at the beginning through last Summer.

    Hummus started a week later.

    I really would like to succeed at losing weight because my sister-in-law is open to my brother eating vegetables right now but if it isn’t helping me lose weight, they don’t really believe the rest of it. Both brothers’ wives are anti-WFPB, and I am now a liability in this whole thing.

    1. Deb, you mentioned about losing weight. Have you checked out Chef AJ who considers herself a former food addict. She also has a facebook group called Fabulous over 40 and she also does interviews with many from the WFPB world including Dr Greger.

  5. The infrared rocks. I am thinking I was eating enough fat that maybe I was still having some of the brain not seeing the leptin thing or something. Or I was eating too late at night, which I still am, and those foods would spike the blood sugar more, but there seems to be a difference with the infrared.

    It could be placebo effects because if it worked for the mice, I happily will take either real effects or placebo effects and will count it all a win-win.

  6. Not related to soy, but could Dr. Greger or a website moderator reply re too much dietary fiber intake, particularly for older folks? After reading Dr. Greger’s book and following the NutritionFacts.org website videos and blogs, I went “Full Greger” on a whole grain and plant based diet. In retrospect, I may have been following Doctor’s orders too explicitly for a 70 year-old digestive system. Since my conversion a couple of years ago, stool has been basically diarrhea. I have recently done some additional research and find that daily fiber intake beyond 70 mg, apparently easily reached on a whole grain and plant based diet, can get messy and should be reduced in any event for people over 50. I hate moving away from the Doctor’s prescription, but have substituted low-fat yogurt, eggs, balsamic rice, and sourdough bread for higher-fiber oatmeal, brown rice, and whole wheat bread with a return to normal re my stool. I worry about the negative impact these foods will have on my heart and arteries but don’t think constant diarrhea is healthy either. I will appreciate your take on this situation. Thank you.

    1. Benton Elliot,

      My husband and I were vegetarian, but about 4-5 years ago, we began to transition to whole plant foods, gradually dropping eggs and dairy products. It took a bit over a year. (We are now 77 and 69, respectively.) And whereas I’ve been vegetarian for almost 50 years, my husband only became one about 12 years ago, after we met and he switched to my home cooking. (He was a widower for about 5 years, and cooking is not one of his skills.)

      And I’ve read that “bananas are binding.” I don’t know if it’s true, but I eat about 1 a day, because I like them — I think they go well with coffee. I also bake my own sourdough whole grain bread; I grind my grains just before I use them. But we only eat from 1-3 slices of bread a day. And I make my own soy yogurt from commercially made soy milk (with only 2 ingredients, water and soybeans), because I couldn’t find soy yogurt in the stores without all kinds of additives. Stuff like that.

      We eat sort of like we did before, only whole plant food based, and limited processed foods, with low added oil, sugar, and salt. We don’t eat much rice, preferring to eat a variety of whole grains, including quinoa, barley, polenta, fonio, farro, etc Lots of soups and stews, simple veggies and fruits. I substituted a serving of beans for the 1 egg I used to eat for breakfast 2-3 times a week; my husband eats granola, and I eat oats the mornings I don’t eat beans.

      And we use Dr. Greger’s daily dozen as guidelines; we rarely hit all 24, but usually manage 20 – 22. It all seems to work for us. We tend not to sweat all the details.

      1. Thanks, Dr. J, for sharing the details of your success with Dr. G’s WGPBD.
        I do include a daily banana in my diet. I will try your suggested quinoa (v. brown rice: less fiber, more nutrients.) Sadly, my cooking skills are rather like your husband’s. Lucky him! Take good care. – Benton

    2. Benton, there is a new book out called Fiber Fueled that will help you with this problem. He has a 4 week food plan to help people ease into fiber and also FODMAP foods if any of those cause you problems. This book is a wonderful new resource for healing digestive issues. Written by a plant-based gastroenterologist.

  7. I was told to avoid soya milk because it “messes with your endocrine system” but I also have endometriosis – an estrogen dependent disease – and I wonder if I shouldn’t re-introduce soy milk if there is a chance it would lower my estrogen levels!

  8. Unfortunately, after introducing more soya into my diet my digestive system has said no. I used to be fine with it, can eat tons of other legumes, but now soya gives me terrible tummy pain and lower abdominal bloating. Rubbish!

  9. As another reader mentioned, you should only consume organic FERMENTED soy. But whatever your choice, make sure it’s ORGANIC and NON-GMO soy in whatever form. I don’t know why this is not discussed more. NON-organic / GMO soy will definitely mess with your gut bacteria and cause digestive issues for many.

    1. Do you have any evidence that non fermented soy, non organic soy and GMO soy are unhealthy? I’d appreciate seeing it if you do.

  10. It’s very confusing – other sites warn against Soya milk saying you should never have it. For example the Empowered Sustenance site that says:

    “Numerous animal studies show that soy phytoestrogens can cause breast cancer. Studies show that soy consumption increases the proliferation of potentially carcinogenic breast cells”

    It provides links to studies in support of what they say.

    1. It’s easy enough to extract isolated ingredients from foods and test their effects in petri dishes on individual human cells. However, the results aren’t necessarily a good guide to what happens when we eat actual food and we examine its effects on the dynamic interactive systems that are our bodies.

      As Harvard University notes

      ‘In animal and cell studies, high dosages of isoflavone or isolated soy protein extracts tend to stimulate breast cancer growth. [13, 14] However, studies that observe people consuming soy foods over time show either a protective or neutral effect’

      and

      ‘The Shanghai Women’s Health Study which followed 73,223 Chinese women for more than 7 years has been the largest and most detailed study of soy and breast cancer risk in a population with high soy consumption. In this study, women who ate the most soy had a 59% lower risk of premenopausal breast cancer compared with those who ate the lowest amounts of soy. Risk was 43% lower when soy was eaten during adolescence. [14] Seven years later, the study authors published a follow-up analysis from the same cohort over 13 years to evaluate any association between soy foods and specific types of breast cancer defined by hormone receptors and by menopausal status (Estrogen [ER] +/-; Progesterone [PR] +/-). [21] Key highlights of the study:

      A 22% lower risk of breast cancer when comparing the highest to lowest intakes of soy during adulthood.
      A 28% decreased risk of hormone positive (ER+, PR+) breast cancer in postmenopausal women.
      A 54% decreased risk of hormone negative (ER-, PR-) breast cancer in premenopausal women.
      A 47% decreased risk of premenopausal breast cancer when comparing high to low intakes of soy during adolescence and adulthood.’
      https://www.hsph.harvard.edu/nutritionsource/soy/

      I can’t see any benefit in believing claims made by people without any relevant qualifications, expertise or skills like the person running the Empowering Sustenance website. It’s probably safer to avoid alternative health claims like those and stick with guidance issued by credible health authorities, leading universities and professional organisations

      ‘According to Marji McCullough, ScD, RD, strategic director of nutritional epidemiology for the American Cancer Society, soy foods are healthy and safe. But she advises against taking soy supplements – which contain much higher isoflavone concentrations than food – until more research is done.’
      https://www.cancer.org/latest-news/soy-and-cancer-risk-our-experts-advice.html

      Listening to the siren song of alternative health ‘experts’ can be dangerous

      ‘After a median of 5 years, patients with breast or colorectal cancer were nearly five times as likely to die if they had used an alternative therapy as their initial treatment than if they had received conventional treatment.’
      https://www.cancer.gov/news-events/cancer-currents-blog/2017/alternative-medicine-cancer-survival

    2. Dr. Greger:

      Since breast and prostate are both hormonal cancers, does soy milk help to combat prostate cancer cells as well?

      1. Please check out this video which should be encouraging on soy use. Dr. Greger has many videos on prostate treatment, if you want to explore further. Just use the Search box and and put in Prostate and many helpful videos will be listed. Hope that helps.

  11. ‘it’s easy enough to extract isolated ingredients from foods and test their effects in petri dishes on individual human cells. However, the results aren’t necessarily a good guide to what happens when we eat actual food and we examine its effects on the dynamic interactive systems that are our bodies’.

    Glad you finally clarified that Tom. Especially given that (with your support) Dr Greger portrayed the binding of beneficial tea polyphenols with milk proteins (but not soy proteins) in the tea cup as irreversible. When in fact, the bindings are reversed during human digestion (in-vivo).

    1. Thanks Pete. But the findings re milk and tea were not reversed in human digestion.

      Sorry to be blunt but you didn’t understand what was said in that Chinese study you quoted from, Darned if I can remember the name of it now but even a quick reading of it revealed where your argument fell over.

      1. Hi Tom,

        Off the top of my head, I clearly remember the ‘Chinese’ study (Zhang et al) you refer to, and all the others. I could resend the whole shebang, but I dont expect you will read it, or it will have so many links it will go missing.
        You are selectively misrepresenting the findings of the multiple studies.
        Which made it absolutely clear. Milk proteins (in fact all proteins, and some fats) bind to tea polyphenols in the teacup (in-vitro), but these bindings are reversed during digestion (in-vivo). Likewise, more than once Dr Greger has completely misrepresented the science on this subject.
        Firstly, when he attempted to portray an ancient in-vitro study (Lorenz et al) as a contemporary in-vivo study. Lorenz rightly finds that tea polyphenols are bound by milk proteins, but fails to establish what subsequently happens during digestion. A rather fundamental oversight – which he is subsequently forced to publicly concede ! Multiple subsequent studies find that these bindings are reversed during digestion (in-vivo), but Dr Greger instead chooses not to include these facts or references in his video. Guess they didn’t fit the narrative ? This is scientific cherry-picking at its worst.
        Incidentally, Zhang et al did NOT find milk proteins bind to tea polyphenols. It found that milk proteins bind to jujube-juice polyphenols.
        Moreover, it found they did so in-vitro, not in-vivo. As this study does not instruct us about the subsequent reversibility of this process, it teaches us nothing of any value. In the same review, Zhang lists all studies where food compounds alter polyphenol bioavailability in-vivo.
        Repeat, in-vivo. Which is where it does get relevant. These studies demonstrate that many proteins and fats (including, but not exclusively milk proteins and fats) bind polyphenols in-vitro, but reverse these bindings during digestion (in-vivo). In many of these studies, fats and proteins (including milk proteins and fats) INCREASE (not decrease) the net bioavailability of polyphenols. Zhang et al do not include their jujube-juice study in this list for an obvious reason. Because it is an in-vitro, not in-vivo study. Therefore, fairly meaningless.

        In another video, Dr Greger falsely claimed soy milk reversed the in-vitro binding of coffee polyphenols, but not cows milk. Dr Greger failed to clarify he based his erroneous claim on a single study of just half a dozen people which emanated from a South American group flogging a new coffee/soy formula. Which, on the basis of your much overworked ‘Big Dairy’ refrain, should have been consigned to the bin. Dr Greger is clearly an outstanding researcher, but when it comes to him and dairy, I find my best friend is that trusty bullship meter lying in the bottom shelf.

        1. Sorry Pete but you have never provided any evidence that milk does not prevent absorption of tea polyphenols or does not suppress tea’s vascular benefits whereas Greger has previously provided evidence that it does. Even here in your latest post, all you have done is once again make assertion after assertion. You have also it seems deliberately declined to provide references to support those assertions. No surprise there given how easy it was to point out the glaring failures in your reasoning last time and the disconnect between what you said the Zhang et al study showed and what the researchers actually said in that paper.

          Milk proteins and fats together may well reverse polyphenol binding in digestion. That is a red herring because there is more than just protein and fat in milk. A million dairy industry studies showing that dairy proteins and dairy fats together do not affect polyphenol absorption, do not invalidate studies examining the effects of consuming milk itself.

          There is for one thing more carbohydrate in milk than either protein or fat. All the studies you refer to show is that neither dairy protein nor dairy fat either singly or in combination can fully explain why adding milk to tea appears to blunt its beneficial effects. Arguing that studies with milk proteins and milk fats show that drinking tea with milk doesn’t blunt tea’s benefits, is misleading. You need to cite studies that examine consuming tea with actual milk rather than some of its component elements.

          ‘Methods and results: A total of 16 healthy female volunteers consumed either 500 mL of freshly brewed black tea, black tea with 10% skimmed milk, or boiled water as control. Flow-mediated dilation (FMD) was measured by high-resolution vascular ultrasound before and 2 h after consumption. Black tea significantly improved FMD in humans compared with water, whereas addition of milk completely blunted the effects of tea. To support these findings, similar experiments were performed in isolated rat aortic rings and endothelial cells. Tea induced vasorelaxation in rat aortic rings and increased the activity of endothelial nitric oxide synthase by phosphorylation of the enzyme in endothelial cells. All effects were completely inhibited by the addition of milk to tea.’
          https://academic.oup.com/eurheartj/article/28/2/219/2887513

          Note that this had nothing to do with either coffee or soy formulas.

          Dairy apologetics is all very well but the evidence appears to support Greger’s position on this issue not yours. Personally, I gave up dairy in tea and coffee long before I began visiting NutritionFacts because I had become aware that populations drinking black tea without milk appeared to derive vascular and mortality benefits whereas populations drinking black tea with milk seemed to have increased risk with increased tea consumption.

          I loved strong black tea with milk and drank gallons of the stuff daily but I don’t try to kid myself that it is healthy..Your long-standing loyalty to the dairy industry shouldn’t blind you to the facts either.

          1. Tom,

            Will answer the last part first. Try and respond to the rest tomorrow. The following is the objective evidence (EFSA) in regards milk in tea and FMD :

            *‘Of the five human intervention studies provided on the chronic effect of black tea consumption on endothelium-dependent vasodilation, two investigated the effect after regular consumption of black tea for a sufficiently long time period (i.e. at least 4 weeks). These two studies did not allow an effect of black tea on endothelium-dependent vasodilation to be established. The Panel concludes that a cause and effect relationship has not been established between the consumption of black tea and maintenance of normal endothelium-dependent vasodilation.©2018 European Food Safety Authority’.*

            ADOPTED: 13 December 2017doi: 10.2903/j.efsa.2018.5138

            Black tea and maintenance of normal endothelium-dependent vasodilation: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006

            https://efsa.onlinelibrary.wiley.com/doi/pdf/10.2903/j.efsa.2018.5138

            Nothing there to get excited about. It is not yet certain polyphenols improve FMD. Which makes the addition of milk to tea somewhat academic. The following is good advice ,from Taipei Hospital:

            ‘*Although the studies (the effect of tea polyphenols on FMD) conducted 11 years apart presented similar findings, their sample sizes were relatively small, Chiang Shuo-ju (**江碩儒), the director of the Division of Cardiovascular Diseases at Taipei City Hospital’s Yangming branch, said on Sunday.*

            *People do not need to avoid drinking milk tea simply because of those findings, he said.*

            *Some people might find black tea, which is fermented tea, bitter and that it upsets their stomach, he said.*

            *Adding a bit of milk can balance out the taste and make people feel fuller, he added.*

            *Huang Shu-hui (黃淑惠), a dietitian at the Postal Hospital in Taipei, said that there is no conclusive answer to the question of whether tea should be drunk with milk.*

            *While there have been studies indicating that the casein in milk interacts with tea catechins to lower the antioxidant effects of catechins, the effects do not completely disappear, she said.*

            *If the catechin concentration in the tea is high enough, it could still provide cardiovascular protection effects, she said.*

            *Black tea, with or without milk, should be steeped in hot water to extract more catechins, she added.*

            *While catechins and caffeine both stimulate the secretion of gastric acid, the protein in milk neutralizes it, she said.*

            *As a result, Huang advised those whose primary concern is to improve antioxidant activity to drink tea without milk, and those who want to avoid upsetting their stomach to add a bit of milk.*

            *The free radicals in the body are unstable molecules that could attack endothelial cells, leading to cardiovascular diseases, Chiang said.*

            *Both green and black tea contain catechins, which increase the amount of nitric oxide in the endothelial cells, allowing blood vessels to dilate and helping to remove free radicals, he said.*

            *Catechins promote endothelial health and reduce the risk of cardiovascular or cerebrovascular pathology, he added.*

            *An eight-week program of brisk walking resulted in a 50% increase in brachial artery FMD in middle-aged and older men, but failed to produce this benefit in estrogen-deficient post-menopausal women.[10] *

            *Forty-five minutes of cycling exercise before sitting has been shown to eliminate the impaired leg FMD due to three hours of sitting.[11] Athletes over age 40 show greater FMD than their age-matched peers.[2] A meta-analysis of 182 subjects showed twice the improvement in FMD resulting from high-intensity interval training compared to endurance training.[6] *

            http://www.taipeitimes.com/News/taiwan/archives/2019/03/30/2003712468 In summary, exercise is the best way to improve FMD, it is not entirely certain tea polyphenols enhance FMD, and if they do, most evidence suggests it is modest. Milk also makes tea more palatable for many, has its own nutritional benefits, and any binding of polyphenols can also be mitigated by steeping the tea differently (or drinking more tea when adding milk).

            1. Thanks Pete.

              I accept that chronic tea drinking has not been shown to deliver permanent vasodilatory effects as set out in that EFSA decision paper. However, that doesn’t invalidate the point that there appear to be short term transient effects as shown in studies such the one quoted in my previous post.

              Regarding, the effect of adding milk to tea on polyphenol/catechin extraction. If I recall from our previous discussion, milk proteins may have been exonerated as a mechanism but it doesn’t automatically follow that whole milk has.

              As for effects, the Rotterdam study suggested a protective effect from drinking black tea but studies from the UK (where black tea is drunk with milk) suggested increased risk with increased tea consumption.
              https://nutritionfacts.org/video/tea-and-artery-function/

              There’s also a Melbourne study which appeared to show an association between tea drinking and stroke risk.
              https://www.ahajournals.org/doi/full/10.1161/01.str.27.11.2020

              Most tea drinkers in Oz seem to take it with milk like people in the UK.

              Taken together, all these points suggest to me that it is prudent to avoid milk in tea. Greger makes a pretty good case for this. You may be right though that it doesn’t satisfy the strict conditions for demonstrating causality. Neither does the evidence against smoking for that matter.

              What is more, I have never seen any evidence that it is more beneficial to take tea with milk than without. If there is no evidence of benefit but suggestive evidence of harm why do it?

              1. Tom

                ‘I accept that chronic tea drinking has not been shown to deliver permanent vasodilatory effects as set out in that EFSA decision paper. However, that doesn’t invalidate the point that there appear to be short term transient effects as shown in studies such the one quoted in my previous post’.

  12. I had endometrial cancer (small c. Very lucky) and full hysterectomy. I’m sorely missing my dear estradiol. My question is if drinking soy milk will change a blood level of whichever estrogen hormone it is…E2 maybe? And if consuming soy milk may help with bone protection and memory? Thanks.

    1. Please check out this video: https://nutritionfacts.org/video/who-shouldnt-eat-soy/ which clarifies the effect of soy: “The effects on the uterus appear also to be mediated solely by alpha receptors—which is, presumably, why no negative impact has been seen with soy. So, while estrogen-containing drugs may increase the risk of endometrial cancer up to ten-fold, phytoestrogen-containing foods are associated with significantly less endometrial cancer—in fact, protective effects for these types of gynecological cancers, in general. Women who ate the most soy had 30% less endometrial cancer, and appeared to cut their ovarian cancer risk nearly in half.
      Soy phytoestrogens don’t appear to have any effect on the lining of the uterus…”You probably will want to review the studies cited with your health care providers so you can feel confident that drinking soy milk with not be harmful to you..

  13. Could you please advise – I have Endometrioma 6 cm (endometriosis), I was recommended to keep a diet without any soy products. I know that there’re studies where endometriosis treatment was the same as for breast cancer so I guess it’s a little similar estrogen affect wise. Should I consume soy products or avoid them at all costs? Thank you

    1. Margarita

      There are many people with websites on the internet who believe that they are geniuses and don’t need to bother with evidence before stating that something is a fact. People saying soy is bad for us appear to be among that group. They never provide evidence for their opinions at best they offer some complicated and usually unintelligent reasoning.

      If soy were an issue for endometriosis, there would very high rates of endometriosis in Japan and China where much more soy is consumed than in the West. There is no good evidence that there are higher rates of endometriosis in those countries. In fact,

      ‘there was only one study from which an estimate of prevalence was obtainable. This was a large survey of nurses from Japan, in which 1025 of 15,019 (6.8%) self-reported endometriosis.[20] The authors of this study found that 89% of women with self-reported endometriosis had a diagnosis confirmed by laparoscopy.[20]’
      https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6367920/

      What is more, another Japanese study found

      ‘We measured urinary levels of genistein and daidzein as markers for dietary intake of soy isoflavones, and genotyped ESR2 gene RsaI polymorphisms.
      Results:
      Higher levels of urinary genistein and daidzein were associated with decreased risk of advanced endometriosis (P for trend = 0.01 and 0.06, respectively) but not early endometriosis. For advanced endometriosis, the adjusted odds ratio for the highest quartile group was 0.21 (95% confidence interval = 0.06–0.76) for genistein and 0.29 (0.08–1.03) for daidzein, when compared with the lowest group. Inverse associations were also noted between urinary isoflavones and the severity of endometriosis (P for trend = 0.01 for genistein and 0.07 for daidzein). For advanced endometriosis, ESR2 gene RsaI polymorphism appeared to modify the effects of genistein (P for interaction = 0.03).
      Conclusions:
      Dietary isoflavones may reduce the risk of endometriosis among Japanese women.’

      https://journals.lww.com/epidem/Fulltext/2007/05000/Effect_of_Soy_Isoflavones_on_Endometriosis_.19.aspx

      I’d avoid listening to the alternative health geniuses on the web who make all sorts of claims without any evidence. Be guided by your doctor/hospital on these matters

      1. Tom,

        You may have missed a significant point with the following …’Higher levels of urinary genistein and daidzein were associated with decreased risk of advanced endometriosis but not early endometriosis’.

        This study (Masaki Tsuchiya, 2007) is not a blanket approval of soy. Which may well decrease the risk in those who already have endometriosis, but conversely increase the risk in females who consume it as pre-pubescents:

        ‘High prevalence of endometriosis was reported in Asian women as a result of their traditionally high intake of soy foods during infancy’.

        This murine study demonstrates pre-pubertal soy consumption increases endometrial risk in adulthood.

        Mvondo et al, 2019

        https://pubmed.ncbi.nlm.nih.gov/30864871/

        On the basis of the following studies, a lower calorie, low fat, high fibre, plant-based diet appears ideal. Which includes dairy, green vegetables, fresh fruit, omega 3’s, and minimises margarine, snack food, packaged baked goods, red meat, beef, ham, and fried fast food. Its possible pre-pubescent females may significantly reduce their risk by consuming milk instead of soy milk:

        1. ‘Some observational studies have shown that plant-based diets and diets high in fibre increase oestrogen excretion and decrease concentrations of bioavailable oestrogen, and thus may lower endometriosis risk.
        Additionally, high-fat diets have been associated with increased serum oestrone, oestrone sulphate and oestradiol levels in premenopausal women, suggesting that diets low in fat and high in fibre may modify endometriosis risk by altering steroid hormone metabolism.

        2. Holly R. Harris et al.,(2013)17 investigated whether intake of dairy foods, nutrients concentrated in dairy foods, and predicted plasma 25-hydroxyvitamin D (25(OH)D) levels were associated with incident laparoscopically confirmed endometriosis among 1,385 cases. Intakes of total and low-fat dairy foods were associated with a lower risk of endometriosis. Women consuming more than 3 servings of total dairy foods per day were 18% less likely to be diagnosed with endometriosis than those reporting 2 servings per day (rate ratio = 0.82, 95% confidence interval: 0.71, 0.95; P trend = 0.03). In addition, predicted plasma 25(OH)D level was inversely associated with endometriosis. Women in the highest quintile of predicted vitamin D level had a 24% lower risk of endometriosis than women in the lowest quintile (rate ratio = 0.76, 95% confidence interval: 0.60, 0.97; P trend = 0.004). Findings suggested that greater predicted plasma 25(OH)D levels and higher intake of dairy foods are associated with a decreased risk of endometriosis.

        3. Britton Traberta et al.,(2010), and Parazzini et al.,(2003) also found a decreased endometriosis risk associated with the consumption of dairy products

        4. …..women with endometriosis were characterized by a greater prevalence of overweight, presented with a high intake of calories and fiber, had lower intake of polyunsaturated fatty acids and had reduction in systemic antioxidant capacity.

        5. Stacey A. Missmer et al.,(2010) found that high consumers of trans fats (margarine, snack food, packaged baked goods, and for frying fast food) dramatically increased the risk. (48% increased risk)

        6. In a study of 20-45 yo women Masaki Tsuchiya.,(2007) found higher urinary levels of genistein and daidzein (soy intake) were associated with a substantially decreased risk of advanced and severe endometriosis, but not early endometriosis.

        7. Green vegetables lowered the risk of endometriosis, whilst ‘milk, liver, carrots, cheese, fish and whole-grain foods, as well as coffee and alcohol consumption, were not significantly related to endometriosis’ (Parazzini et al, 2003)

        8. Parazzini et al.,(2003) found a high intake of beef and red meat and ham increased endometriosis risk.

        https://www.researchgate.net/publication/282006175_Diet-_A_new_approach_to_treating_endometriosis_-_What_is_the_evidence

  14. Some colleagues argue that soy milk is very rich in inflammatory w-6 compounds and phyitic acid. Is there any way to reduce these high amounts?
    Thanks

    1. Soy milk is mostly water so unless you are drinking significant amounts every day, it is unlikely to matter much one way or the other.

      Also, why would you want to reduce an anti-cancer substance like phytic acid?
      https://www.researchgate.net/publication/229471466_Anti-cancer_function_of_phytic_acid

      Further, if you are taking 250 mg of an omega 3 supplement. and one tablespoon of ground flaxseed daily, as recommended by Dr Greger, your omega 3/6 ratio is likely to be excellent – soy milk or no soy milk.

  15. Making naturally occurring, organic (where possible) vegetable quality (non dairy) foods, including whole grains, the foundation of your diet is an essential part of enjoying good health and healing. The science speaks for itself, your intuition and the value of good counsel must do the rest.

  16. I was set on following a plant based diet until the Hashimotos, thyroid, SIBO, IBS people said low carb, no grains, gluten free is way to eat for those issues. And that soy is inflammatory and legumes don’t digest well in People with IBS. I do eat some organic soy though and don’t notice negative effects. I’m so conflicted with diet it’s crazy. And have osteoporosis on top of everything. What do people think about Paleo with lots of veggies for autoimmune issues vs plant based?

    1. Are you getting this advice from credible sites like national health authorities, official guidelines, professional medical associations and leading universities? Or does it come from dubious websites and YouTube videos by people with very strong opinions but little or no specialist expertise?

      As for paleo with lots of vegetables, that’s basically a diet containing lots of red meat plus fruits and vegetables (FV)

      ‘Compared with participants in the lowest quintile of total red meat consumption, those in the highest quintile had a 21% increased risk of all-cause mortality (HR: 1.21; 95% CI: 1.13, 1.29), a 29% increased risk of CVD mortality (HR: 1.29; 95% CI: 1.14, 1.46), and no increase in the risk of cancer mortality (HR: 1.00; 95% CI: 0.88, 1.43). Results were remarkably similar across amounts of FV consumption, and no interaction between red meat and FV consumption was detected.

      Conclusion: High intakes of red meat were associated with a higher risk of all-cause and CVD mortality. The increased risks were consistently observed in participants with low, medium, and high FV consumption.’
      https://academic.oup.com/ajcn/article/104/4/1137/4557128

  17. Sarah,

    Interesting article with lots of assumptions. Let’s start with the most glaring and obvious. There is no question that a large number of our world population is indeed deficient or lacking the optimal intake of nutrients, regardless of their diet.

    Do vegan diets demand more B12, omega 3’s, vitamin d and potentially other nutrients, yes and I’d direct you to the many Dr. G’s videos addressing these considerations.

    As was pointed out in the article the is a major issues with having people take adequate supplementation. Taking kids in Kenya in the Embu district ( Embu district is an area of mixed agriculture, with mostly subsistence agriculture and some cash crops, primarily coffee, cotton and tobacco. The primary dish consumed in the region is githeri, a vegetable stew composed of maize, beans, vegetable oil and some greens.) and doing the quoted study lacks many issues of a science based design, as we don’t have more detailed intakes for their home diets, as one example, let alone full blood and urine panels to evaluate other toxic intakes (metals to the mirid of water and soil contaminants, to plastics) which could have accentuated the deficits and lead to the outcomes.

    But let’s also look at the abstract and pause: “There were no group differences on tests of verbal comprehension. Results suggest that supplementation with animal source food has positive effects on Kenyan children’s cognitive performance. However, these effects are not equivalent across all domains of cognitive functioning, nor did different forms of animal source foods produce the same beneficial effects.” For a much more in depth look at how the testing and results was accomplished see the whole publication at: https://academic.oup.com/jn/article/133/11/3965S/4818056

    Employing cognitive testing to determine that meat or dairy is needed for vegan diets based on suboptimal intakes of Keyon children in one tribe who are already at nutrient risk and then extrapolating this to anyone else is questionable at best. I admit to not being an expert on this tribe or the area’s ecology however I would want to see a very different basis of testing before concluding that vegan diets, in all but this isolated situation are inadequate, other than what we know in broad categories where we encourage supplementation.

    You’re right to question the BBC and in this case their seeking to apply limited info to more than an appropriate group and not use more current data (the study was done in 2003). Couple this with the headline…. good news they used the word “could” and included some comments by others who were less derogatory towards a vegan diet. The highly provocative statements by David Benton on cases that were truly tragic are important, but isolated. The comments about those in India with “endemic lack of B12” is clearly headline grabbing, but not particularly new news or surprising. And waiting to the end of the article to include Heather Russell, a dietitian from The Vegan Society and her statement.

    Perhaps the real take home message should be that a balanced WFPB diet, with supplementation, is actually the best method of insuring a healthy nutrient intake that results in adequate function both from childhood to geriatrics ?

    Nutrition is still very much in its infancy as we are constantly learning that the interplay between the various nutrients coupled with our unique genetic makeup, environment and other factors are contributing to our cognitive and other bodily functions. Do we actually know what’s ideal for you as an individual, not really at a detailed molecular level.

    The good news is that as science evolves and our ability to test multiple parameters becomes more available and accurate, we can modify and optimize. At this point in time, WFPB diets appear to be an option for many that will increase their nutrient intake density and result in less disease.

    Dr. Alan Kadish moderator for Dr. Greger http://www.Centerofhealth.com

    PS. I loved the image of a fat laden burger, with bacon….. somehow it really does say a ton about the

    1. Dear Dr Kadish, I really appreciate the comments which were most interesting. I am going to contact the BBC forthwith!

  18. Wed, 22 Jul,

    In response to To Tom…

    ‘I accept that chronic tea drinking has not been shown to deliver permanent vasodilatory effects as set out in that EFSA decision paper. However, that doesn’t invalidate the point that there appear to be short term transient effects as shown in studies such the one quoted in my previous post’.

    ——————————————–

    That’s the whole point Tom. It’s transient (reversible), so therefore of no real net consequence. Its quite simple, milk (including soy milk) or any protein added to polyphenol-rich tea, coffee, cocoa, blueberries etc causes the polyphenols to be bound to the protein (eg soy or milk proteins). Any number of studies tell us this. However, this does not amount to much, other than in some instances it enhances polyphenol bioavailability. As do some other carbohydrates and fats in the food matrix. Mostly there is net loss of polyphenol bioavailability. A few studies demonstrate a miniscule loss, but this is negated by changing a few parameters. For example, increasing the quantity, consumption frequency, temperature, or steeping time of tea.

    We have a large number of in-vitro studies which teach us that milk proteins complex with polyphenols pre-digestion, that is, in the mug. Or in the chocolate block. Or in the fruit salad and cream. But so what? To my mind these studies are just a complete waste of someone’s money. They should demand a refund. The only thing that really counts are in-vivo studies, and they demonstrate these complexes are reversed during digestion. As Shakespeare says, ‘its much ado about nothing’. .

    ———————————-

    Regarding, the effect of adding milk to tea on polyphenol/catechin extraction. If I recall from our previous discussion, milk proteins may have been exonerated as a mechanism but it doesn’t automatically follow that whole milk has.

    ——————————————————————————————

    Tom, ‘milk proteins are not exonerated. They ARE the ‘problem’. All proteins are the ‘problem’, including soy proteins. But they are an easily reversible ‘problem’. Swallow the milk protein/polyphenol brew and allow your digestive system to deal with it. To cleave apart the protein/polyphenol complexes. As one would expect of a digestive system which has had many thousands of years to figure it out. That is, to maximise the nutritional benefit of the ingested food matrix, rather than allow it to simply ‘pass through’.

    ——————————————————————————————————-

    As for effects, the Rotterdam study suggested a protective effect from drinking black tea but studies from the UK (where black tea is drunk with milk) suggested increased risk with increased tea consumption.
    https://nutritionfacts.org/video/tea-and-artery-function/

    ——————————————————

    Tom, I dont hold this sort of association very highly. Tea lowers the risk of FMD, except in the UK because they add milk to their tea. Not very convincing (the Chinese Imperial Court ‘invented’ milk tea hundreds of years ago). Based on the vast amount of evidence (I will send, if I can do so without breaking your server), it is bound to be something else.

    Bear in mind, the FMD benefit from tea is either non-existent or minimal. As determined by EFSA. Therefore, milk cannot possibly ‘completely blunt’ its effect. As claimed by Dr Greger. Especially as he is quoting an in-vitro study (Lorenz et al, 2007), which was effectively conceded as worthless by the authors way back in 2007. I will send you the details.

    ———————————————————————–
    ‘There’s also a Melbourne study which appeared to show an association between tea drinking and stroke risk.
    https://www.ahajournals.org/doi/full/10.1161/01.str.27.11.2020

    Most tea drinkers in Oz seem to take it with milk like people in the UK.

    ‘Taken together, all these points suggest to me that it is prudent to avoid milk in tea’.

    ——————————————————-

    Tom, it makes little or no no difference, other than it tastes better and you get the benefit of milk as well as the tea polyphenols. If its coffee or cocoa with milk, I expect your polyphenol bioavailability might increase, not decrease. If you homogenise milk with coffee (admittedly, not easy), you will get a huge increase in polyphenol bioavailability. This is not very helpful, other than teaching us there is huge potential for milk to increase coffee polyphenol bioavailability, if they figure out the processing side.

    ———————————————————————————————-

    ‘Greger makes a pretty good case for this’.

    ———————————————————–

    On the contrary Tom, his performance in this particular video is a complete disgrace. A real low point. Its just shabby pseudo-science, bordering on ‘fake news’. I would happily debate the issues any time.

    —————————————————————————————

    ‘You may be right though that it doesn’t satisfy the strict conditions for demonstrating causality. Neither does the evidence against smoking for that matter’.

    What is more, I have never seen any evidence that it is more beneficial to take tea with milk than without. If there is no evidence of benefit but suggestive evidence of harm why do it?’

    ——————————————————-

    this is probably true Tom, but Dr Greger is advising us not to add milk because it ‘completely blunts’ the beneficial effect of polyphenols, and interchange soy milk instead. Which he asserts does not have this blunting effect. Its completely untrue, and he knows it, or should know it. This is what I am responding to. Whether one gets a net benefit from adding milk is less clear. Probably not, but it’s quite complicated. The minerals and fat in milk increase bioavailability, and the protein in milk initially decreases it, but the latter is reversed during digestion. Also, the measuring/testing methods are inconsistent. So, its a bit messy. Incidentally, there are studies which demonstrate milk increases the polyphenol bioavailability of green tea catechins…so who knows? I will try and send them (easier said than done). If sufficiently interested you can read them. There are 30 studies, so you will not have cause to again complain: …..’Sorry Pete but you have never provided any evidence that milk does not prevent absorption of tea polyphenols or does not suppress tea’s vascular benefits’

    PREAMBLE

    A little preamble to give you an overview of the issues:

    ‘Several studies have found that adding milk to tea decreases its antioxidant capacity, or how effective its antioxidants are at preventing oxidation.

    This effect is thought to occur because the milk protein casein binds with antioxidants, reducing their ability to fight harmful free radicals (Barrasa et al, 2013, https://pubmed.ncbi.nlm.nih.gov/24001682/)

    However, the results have been conflicting. While some studies show that milk decreases the antioxidant capacity of tea, other studies show that it has no effect or even a positive effect (Rashidinedad et al –2017, https://pubmed.ncbi.nlm.nih.gov/26517348)

    For example, one study assessed three different measures of antioxidant capacity in tea. One test found that adding milk protein to tea reduced its antioxidant capacity by 11–27% (Barrasa et al, 2013)

    However, another test (from the same authors) using a different measure found that milk protein improved antioxidant capacity from 6% to 75% (Barrasa et al, 2013)

    Yet, two other studies found that milk had no effect on the antioxidant capacity of tea in human participants (Leenan et al, 2000 – https://pubmed.ncbi.nlm.nih.gov/10694777/, and Reddy et al, 2005 – https://pubmed.ncbi.nlm.nih.gov/16020939/).

    The results are likely varied due to the type of tea, the type and amount of milk, the way the tea was prepared and the way the antioxidant capacity was measured.

    Taylor Jones, RD – https://www.healthline.com/nutrition/does-milk-block-antioxidants

    Consider carefully the Barrasa et al, experience (above). One of their measurement methods demonstrated milk reduced antioxidant capacity, and the other demonstrated milk increased antioxidant capacity. Which suggests the measurement method strongly determined outcomes. Likewise the in-vivo measurements of metabolites. Additionally, the above are in-vitro studies, not in-vivo studies. Meaning they do not examine if these complexes are reversed during digestion. Most research tends to suggest post-digestive reversal of milk/polyphenol complexes. In which case, in-vitro studies are rather meaningless.
    This is covered in the latest study on this subject, which comes from Urbanska et al, April 2020:

    ‘Regardless of the decreasing antioxidant reduction potential in vitro studies, in many works,among others, Serafini, et al. [53], Loffredo, et al. [58], and Di Mattia, et al. [1], the same trend is not observed in studies on living organisms. In all these studies, the results of the increase in the occurrence of specific antioxidants in plasma consumed in the vicinity of milk did not differ significantly from those of milk-free counterparts. Such dependence may mainly result from the conditions of the digestive process of living organisms and many transformations and changes of substances that may occur as a result. Decreases in the amount determined in the body of epicatechin patients were recorded in studies by Neilson, et al. [59] after consumption of cocoa products containing milk. In each case, however, these values, although lower, did not show statistically significant differences.This phenomenon was explained by the variability of intestinal capture of food components and their subsequent transport between cells in patients’ organisms. It follows that lowering the antioxidant character of cocoa in a product with the addition of milk, such as milk chocolate, may be of primarily technological importance’.

    https://www.mdpi.com/2076-3921/9/4/299/pdf.

    Note, the addition of milk to cocoa is primarily of technological (production) importance, not medicinal importance. This is a long-winded way of saying that in-vitro milk/polyphenol complexes in cocoa are reversed during digestion, with little or no antioxidant loss. This is entirely consistent with many similar studies with tea and coffee.

  19. The following post is directed at Tom, as a follow-up to my post yesterday. As promised.
    Dr Greger claims that adding milk to tea, coffee, cocoa ‘completely blunts’ the medicinal benefit of their polyphenols. As opposed to soy milk, which does not. The following 30 studies demonstrate this is untrue. Characteristically, Tom makes various counter-assertions in regards my criticism of Dr Greger’s claims. See following. This post addresses these allegations. Tom is urged to carefully read this post. Dr Greger is urged to withdraw his misleading video.

    Toms Allegations:
    ‘To use Pete’s own words, his posts are ‘highly selective and misleading reporting’ of the evidence by a long-time milk and dairy advocate. Pete’s argument relies on people,not having the time to read the long list of papers he cites and quotes from, to get the full picture’.

    ‘Pete accuses Dr Greger and this video of highly selective and misleading reporting on this issue. He maintains that the evidence shows that milk doesn’t impair absorption. he then posted a whole list of citations with some very selective quotations’.

    ‘They don’t support his claim that drinking black tea with milk doesn’t impair absorption’

    ‘Not only do those papers not prove Pete’s claim, they directly contradict it’ (this refers to Zhang et al, 2014, below)’.

    ‘One of them, the Moser paper, even compares the effect of some constituent parts of milk – the proteins – against others (the salts) on the absorption of flavonols from green tea, and wants us to believe that this somehow shows that drinking milk in black tea doesn’t impair flavanol absorption’.

    Tom is thoughtlessly replicating Dr G’s unscientific, anti-dairy propaganda. I am not going to post up to thirty studies, or even their abstracts. For brevity, I quote only the parts that address the assertions made by Dr Greger in his video. That is, do polyphenols provide a medicinal benefit; does milk diminish polyphenol bioavailability and thereby this potential medicinal benefit; and is there any substantive difference between soy and cows milk in this regard? The short answer is no, no, and no.

    A. Moser et al

    ‘Milk protein, most notably sodium caseinate, significantly decreased (p <0.05) bioaccessibility of flavan-3-ols relative to JK buffer controls (10 relative to 32%).

    Interestingly, the presence of milk minerals significantly increased (p < 0.05) flavan-3-ol bioaccessibility compared to that of controls (32 relative to 18%).

    These data combined with SDS-PAGE and fluorometric analyses suggest that both milk proteins and minerals may alter flavan-3-ol bioaccessibility, but normal GI digestion appears to minimize the impact of specific protein interactions.

    [interpretation: milk minerals increased flavanol bioaccessibility, milk proteins reduced bioaccessability pre-digestion (in-vitro), but this is reversed post digestion (in-vivo)].

    Moser et al, 2014

    https://www.sciencedirect.com/science/article/abs/pii/S0963996914006188

    page 90 …..’Interestingly, bioaccessibilities of all flavan-3- ols were significantly improved by addition of milk mineral rich JK buffer to beverage formulation relative to dd (distilled) water (Figure 7, Table 10). This effect was likely due to presence of divalent metal ions including calcium (Ca) and magnesium (Mg)’

    page 92 – ‘Beverages formulated with NFDM (non-fat dried milk) were found to have significantly higher (p50%’
    ’Milk presence and HPH also improved α-glucosidase inhibitory capacity of coffee’.

    Alongi et, 2019
    https://www.sciencedirect.com/science/article/abs/pii/S1756464619302415

    ‘Administration of GTPM (green tea polyphenol infused with milk) significantly increased (p < 0.05) the antioxidant index and antioxidant enzyme activities when compared with the placebo group, whereas a concomitant decrease in the levels of lipid peroxidation were noted’.

    Chiu et al, 2016
    https://pubs.rsc.org/en/content/articlelanding/2016/fo/c5fo01271f#!divAbstract

    ‘These in vitro observations are consistent with several clinical studies that have reported milk addition generally does not impact acute absorption of flavan-3-ols from black or green tea in humans’.

    ‘It is very unlikely that consumption of tea with or without milk will result in differences in catechin plasma concentration’.

    Van der Burg-Koorevaar et al. (2011)
    https://www.researchgate.net/publication/51237698_Effect_of_Milk_and_Brewing_Method_on_Black_Tea_Catechin_Bioaccessibility

    …a feeding study by Renouf et al.243 revealed no difference in the pharmacokinetic profiles of plasma acyl-quinic acid metabolites after drinking black coffee with or without 10% whole milk. Thus, although 5-CQA has been reported to bind to certain proteins in vitro, such as albumin and casein,244,245 milk would appear not to have a significant impact on the overall absorption of coffee acyl-quinic acids.

    However, adding a mixture of sugar and non-dairy creamer (these are traditionally made from soybean oil and lecithin) to the black coffee resulted in lower Cmax values for caffeic acid (3) and isoferulic acid (43) accompanied by longer Tmax times for ferulic acid (4) and isoferulic acid.243 Sugar246 and lipids247 are known to delay gastric emptying and this may have delayed absorption of the coffee acyl-quinic acids resulting in an extended Tmax for two of the three metabolites.

    Clifford et al, 2017
    https://pubs.rsc.org/en/content/articlehtml/2017/np/c7np00030h

    One might well ask why Dr Greger chose to quote two unreliable or discredited studies (Lorenz et al, 2007, and Felberg et al) to create a completely false impression, whilst sidelining up to 30 studies which demonstrate the complete opposite.

    My References:

    1. Rashidinejad et al, 2017

    …there are ‘similar effects between soy and bovine milk’ –

    ‘There is a conflicting evidence of the effect of milk addition to tea on antioxidant activity. Differences in the type of tea, the composition, type and amount of milk, preparation method of tea-milk infusions, the assays used to measure antioxidant activity, and sampling size likely account for different findings’. (there are) ‘similar effects between soy and bovine milk’.

    https://www.ncbi.nlm.nih.gov/pubmed/26517348

    2. Green et al, 2007

    Less than 20% of green tea catechins survive digestion, independent of any milk addition (Green et al, 2007). If we are to believe Dr Greger, the addition of milk reduces this to 0%. However, Green et al demonstrates that the addition of milk INCREASES the 20% polyphenol bioavailability to 52%. (adding soy milk, rice milk, ascorbic acid and particularly citrus juice elevates it even higher).

    Catechin stability in green tea was poor with <20% total catechins remaining post-digestion. EGC and EGCG were most sensitive with less, not double equals 10% recovery. Teas formulated with 50% bovine, soy, and rice milk increased total catechin recovery significantly to 52, 55, and 69% respectively. Including 30 mg AA in 250 mL of tea beverage significantly (p50%’

    ’Milk presence and HPH also improved α-glucosidase inhibitory capacity of coffee’.

    [Homogenised milk more than doubled chlorogenic acid bioavailability and improved alpha-glucosidase inhibition – which is of particular benefit to diabetics]

    https://www.sciencedirect.com/science/article/abs/pii/S1756464619302415

    7. Draijer et al, 2016

    ‘Compared to capsule ingestion, consumption of polyphenol-rich beverages containing either dairy, soy or no proteins had minor to no effect on the bioavailability and excretion of phenolic compounds in plasma (118% ± 9%) and urine (98% ± 2%). We conclude that intake of polyphenols incorporated in protein-rich drinks does not have a major impact on the bioavailability of a range of different polyphenols and phenolic metabolites’.

    https://www.ncbi.nlm.nih.gov/pubmed/27983686

    8. Mullen et al, 2017.

    ‘Milk decreases urinary excretion but not plasma pharmacokinetics of cocoa flavan-3-ol metabolites in humans.

    [Note 1. Urine-excreted metabolites of polyphenols are not a reliable measure of plasma pharmacokinetics. Note 2. Non-alkalised raw organic cocoa has much higher polyphenol levels than conventional ‘dutch’ cocoa].

    https://www.ncbi.nlm.nih.gov/pubmed/19403635

    9. Zhang et al, 2014

    …. ‘when plant phenols are consumed along with food macronutrients, the bioavailability and bioactivity of polyphenols can be significantly affected. The protein–polyphenol complexes can significantly change the plasma kinetics profile but do not affect the absorption of polyphenols’

    Table 2 demonstrates a multitude of macronutrients (not just milk) in the food matrix which affect polyphenol bioavailability.

    https://tinyurl.com/u8hvw9n

    10. Lamothe et al, 2014

    ‘The presence of dairy matrices significantly improved polyphenol stability in the intestinal phase and increased the antioxidant activity by 29% (cheese) to 42% (milk) compared to the control. These results suggest that simultaneous consumption of green tea and dairy products helps to maintain the integrity and antioxidant activity of polyphenols during digestion’.

    https://www.ncbi.nlm.nih.gov/pubmed/25154916

    11. van der Burg-Koorevaar et al, 2011

    …..’the bioaccessibilities of TCAT of tea with milk versus tea controls were comparable (p > 0.05). The type of milk did not influence TCAT recovery during all digestive stages (p > 0.05). Polyphenol-protein complexes are degraded during digestion. It is very unlikely that consumption of tea with or without milk will result in differences in catechin plasma concentration’.

    https://www.ncbi.nlm.nih.gov/pubmed/21692489

    12. Leenan et al, 2000

    ‘Consumption of a single dose of black or green tea induces a significant rise in plasma antioxidant activity in vivo. Addition of milk to tea does not abolish this increase’.

    A_single_dose_of_tea_with_or_without_milk_increases_plasma_antioxidants_in_humans

    https://www.researchgate.net/publication/12620409

    https://pubmed.ncbi.nlm.nih.gov/10694777/

    13. Van Het – 1998

    ‘Catechins from green tea and black tea are rapidly absorbed and milk does not impair the bioavailability of tea catechins’.

    https://www.ncbi.nlm.nih.gov/pubmed/9630386

    14. Haratifar et al – 2014,

    Numerous studies have demonstrated that tea catechins form complexes with milk proteins, especially caseins. Much less work has been conducted to understand the metabolic conversions of tea-milk complexes during gastro-duodenal digestion. The objective of this study was to determine the significance of this association on the digestibility of the milk proteins and on the bioaccessibility of the tea polyphenol epigallocatechin gallate (EGCG). An in vitro digestion model mimicking the gastric and duodenal phases of the human gastrointestinal tract was employed to follow the fate of the milk proteins during digestion and determine the bioefficacy of EGCG isolated or encapsulated with the caseins.

    The results demonstrated that regardless of the extent of digestion of the nanoencapsulated EGCG, the bioefficacy of EGCG was not diminished, confirming that casein micelles are an appropriate delivery system for polyphenols.

    https://www.ncbi.nlm.nih.gov/pubmed/24686838

    15. Cebeci et al, 2014

    … ‘it was not possible to detect catechin in mixtures due to milk addition. In vitro digestion method was used to determine potential bioavailability of phenolic compounds. According to in vitro digestion procedure results, whole or skimmed milk did not affect the total phenolic content of the proportion passing to the blood from intestine’.

    https://www.ncbi.nlm.nih.gov/pubmed/23944181/

    16. Neilson et al – 2009

    ‘Areas under the serum concentration−time curve (AUC) were similar among chocolate matrices. However, in-vitro AUCs were significantly increased for sucrose/milk/protein cocoa beverages, and non-nutritive sweetener milk protein cocoa beverages. In vitro bioaccessibility and Caco-2 accumulation did not differ between treatments. These data suggest that bioavailability of cocoa flavan-3-ols is likely similar from typical commercial cocoa based foods and beverages, but that the physical form and sucrose content may influence TMAX and CMAX.’

    https://pubs.acs.org/doi/10.1021/jf902919k

    17. Keogh et al. (CSIRO, 2017)

    In order to determine whether milk proteins interact with cocoa polyphenols to modulate the uptake and concentration of polyphenols in plasma, 24 middle‐aged men and women consumed 2 g of chocolate polyphenols, plus sugar and cocoa butter in 200 mL water, on 2 occasions. On 1 occasion, the chocolate mix contained 2.45 g of milk proteins. Blood samples were taken fasting and at regular intervals for 8 h. Catechin and epicatechins levels were measured in these samples and no differences were seen in average concentrations between the 2 treatments. Milk protein caused a slight increase in concentration at the early time points and a decrease at the later time points. In conclusion, milk powder did not influence the average concentration of polyphenols. While it slightly accelerated absorption, this is of no physiological significance.

    https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1750-3841.2007.00314.x

    18. Roura et al, 2008

    ‘The results show that milk does not significantly affect the total amount of (cocoa) metabolites excreted in urine’.

    ‘The matrix in which polyphenols are consumed can affect their metabolism and excretion, and this may affect their biological activity.

    https://www.ncbi.nlm.nih.gov/pubmed/18257943

    19. Roura et al, 2007

    ‘Cocoa powder dissolved in milk as one of the most common ways of cocoa powder consumption seems to have a negative effect on the absorption of polyphenols; however, statistical analyses have shown that milk does not impair the bioavailability of polyphenols and thus their potential beneficial effect in chronic and degenerative disease prevention’.

    https://www.ncbi.nlm.nih.gov/pubmed/18032884

    20. Moser et al, 2014

    Milk protein, most notably sodium caseinate, significantly decreased (p <0.05) bioaccessibility of flavan-3-ols relative to JK buffer controls (10 relative to 32%).

    Interestingly, the presence of milk minerals significantly increased (p < 0.05) flavan-3-ol bioaccessibility compared to that of controls (32 relative to 18%).

    These data combined with SDS-PAGE and fluorometric analyses suggest that both milk proteins and minerals may alter flavan-3-ol bioaccessibility, but normal GI digestion appears to minimize the impact of specific protein interactions.

    [milk minerals increased flavanol bioaccessibility, milk proteins reduced bioaccessability in-vitro, but this was reversed in-vivo].

    https://www.sciencedirect.com/science/article/abs/pii/S0963996914006188

    21. Khan et al, 2014

    …’carbohydrates and proteins, along with the complex food matrix and cocoa product physical stage (liquid vs. solid) were also considered to interfere in the mechanism of flavanol uptake, affecting the bioaccessibility and bioavailability of cocoa polyphenols in human subjects’.

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3942736/

    22. Khan et al, 2012

    ‘Consumption of cocoa power with milk modulates the lipid profile in high-risk subjects for CHD. In addition, the relationship observed between the urinary excretion of cocoa polyphenol metabolites and plasma HDLc and oxLDL levels suggests a beneficial role for cocoa polyphenols in lipid metabolism’.

    https://www.ncbi.nlm.nih.gov/pubmed/21550218

    23. Renouf et al (2010)

    ‘As a conclusion, adding whole milk did not alter the overall bioavailability of coffee phenolic acids, whereas sugar and nondairy creamer affected the Tmax and Cmax but not the appearance of coffee phenolics in plasma.

    https://academic.oup.com/jn/article/140/2/259/4600297

    24. Farah et al, 2019

    … ‘about one third of the consumed chlorogenic acid from coffee is absorbed in the human gastrointestinal tract’ (that is, about two-thirds of chlorogenic aid is lost during digestion, that is, unrelated to the addition of milk)

    ‘Even in-vitro, higher fat milk added to coffee strongly increases the bioaccessibility of chlorogenic acids.

    ‘the addition of 10% whole milk or a pre-mixed non-dairy (fat rich) creamer with sugar to coffee did not increase or decrease chlorogenic acids area under the curve in plasma, in despite of a delay in chlorogenic acids appearance observed in the creamer test’

    ‘soy protein and/or other substances present in soymilk also bind chlorogenic acids decreasing their absorption in the upper digestive tract. This corroborates in vitro results on interactions between chlorogenic acids and soy protein

    ‘Brazil has implemented an active coffee school programme based on the findings that 20% coffee added to a glass of whole milk helps children perform better in school (ABIC, 2016)’

    ‘Consumption of Chlorogenic Acids through Coffee and Health’ …

    https://www.mdpi.com › pdf-vor
    https://pubs.rsc.org/en/content/chapter/9781788015028-00364/978-1-78801-502-8

    25. Elikoglu et al (2017) ‘milk proteins and dairy products represent unique characteristics for polyphenol studies. The conflicting results on the functionality of polyphenols interacting with milk proteins either in model systems or in complex dairy matrices reveal the need for future studies’.

    https://www.tandfonline.com/doi/full/10.1080/87559129.2017.1377225

    26. Reddy et al. (2005) . ‘Addition of Milk Does Not Alter the Antioxidant Activity of Black Tea’

    ….’the results suggest that addition of milk may not obviate the ability of black tea to modulate the antioxidant status of subjects and that consumption of black tea with/without milk prevents oxidative damage in vivo’.

    https://www.karger.com/Article/Abstract/87071

    27. Kyle et al, 2007.

    ‘Six brands of tea demonstrated similar increases in antioxidant capacity and total phenolic and catechin contents with increasing infusion time. These results were unaffected by the addition of milk. Consumption of black tea (400 mL) was associated with significant increases in plasma antioxidant capacity (10%) and concentrations of total phenols (20%), catechins (32%), and the flavonols quercetin (39%) and kaempferol (45%) (all p < 0.01) within 80 min. This was unaffected by adding milk. Infusion time may therefore be a more important determinant in the absorption of polyphenols from black tea.

    https://www.ncbi.nlm.nih.gov/pubmed/17489604

    28. Heiss et al, 2007. ‘subjects consumed high-flavanol cocoa drinks (dry dairy-based beverage mix made with cocoa powder containing 306 mg of flavanols mixed in 100 mL of water) 3 times daily, totalling 918 mg of daily flavanol intake.

    We demonstrated that the daily consumption of a high-flavanol cocoa drink leads to a sustained reversal of endothelial dysfunction, reaching a plateau level of improved FMD at approximately day 5 (Figure 1). The magnitude of sustained vascular effects observed in the present study was in a range similar to that observed after long-term pharmacological approaches with, for example, statins.

    https://www.chococru.com/wp-content/uploads/2017/11/Heiss-et-al.-2007.pdf

    29. Karaarslan et al , 2007

    ‘The yogurts supplied with grape callus extract displayed the greatest antioxidant power on the first day of storage compared to all the assayed samples…..analysis revealed the presence of at least 10 individual bioactive phenolic compounds in the callus yogurt. The results obtained from this investigation shows that grape callus culture has a potential to be used as a food supplement to play a role in reducing the risk of developing chronic diseases such as cancer and cardiovascular disease’.

    http://europepmc.org/abstract/AGR/IND44580698

    30. Monteiro et al (2007)

    ‘urine does not appear to be a major excretion pathway of intact chlorogenic acid compounds in humans’.

    https://www.ncbi.nlm.nih.gov/pubmed/17884997

    31. Rawel et al, 2017

    ‘Soy glycinin (SG) and soy trypsin inhibitor (STI) were derivatized by chlorogenic- and caffeic acid (cinnamic acids, C(6)-C(3) structure), and by gallic acid representing hydroxybenzoic acids (C(6)-C(1) structure). Further, the flavonoids, flavone, apigenin, kaempferol, quercetin and myricetin (C(6)-C(3)-C(6) structure) were also caused to react with soy proteins’…

    [Soy proteins (amongst many other macronutrients) bind with polyphenols].

    https://www.ncbi.nlm.nih.gov/pubmed/12063116

  20. This post attempts to address the various assertions made by both Dr Greger and Tom in regards the addition of milk to tea, coffee or cocoa..It appears large slabs of my post from yesterday did not get published. Either my technical incompetence or the nutrition-facts server could not deal with it. No matter, here they are. They demonstrate milk does not irreversibly bind to polyphenols, and that these in-vitro complexes are ultimately broken down during digestion. That is, there is no loss of polyphenol bioavailability. Moreover, the claimed ability of tea polyphenols to influence FMD is not proven. Thereby, milk cannot diminish this ability. On the evidence, Dr Greger’s video on this subject is inaccurate and highly misleading.
    Tom raises studies by Moser et al, and Zhang et al. They are detailed below. Dr Greger selectively quotes Lorenz et al, 2007 and Felberg et al. I also outline them below and detail why they are unreliable or discredited studies:

    A. Re Moser et al

    ‘Milk protein, most notably sodium caseinate, significantly decreased (p <0.05) bioaccessibility of flavan-3-ols relative to JK buffer controls (10 relative to 32%).

    Interestingly, the presence of milk minerals significantly increased (p < 0.05) flavan-3-ol bioaccessibility compared to that of controls (32 relative to 18%).

    These data combined with SDS-PAGE and fluorometric analyses suggest that both milk proteins and minerals may alter flavan-3-ol bioaccessibility, but normal GI digestion appears to minimize the impact of specific protein interactions.

    [interpretation: milk minerals increased flavanol bioaccessibility, milk proteins reduced bioaccessability pre-digestion (in-vitro), but this is reversed post digestion (in-vivo)].

    Moser et al, 2014

    https://www.sciencedirect.com/science/article/abs/pii/S0963996914006188

    page 90 …..’Interestingly, bioaccessibilities of all flavan-3- ols were significantly improved by addition of milk mineral rich JK buffer to beverage formulation relative to dd (distilled) water (Figure 7, Table 10). This effect was likely due to presence of divalent metal ions including calcium (Ca) and magnesium (Mg)’

    page 92 – ‘Beverages formulated with NFDM (non-fat dried milk) were found to have significantly higher (p50%’
    ’Milk presence and HPH also improved α-glucosidase inhibitory capacity of coffee’.
    Alongi et, 2019

    https://www.sciencedirect.com/science/article/abs/pii/S1756464619302415

    ‘Administration of GTPM (green tea polyphenol infused with milk) significantly increased (p < 0.05) the antioxidant index and antioxidant enzyme activities when compared with the placebo group, whereas a concomitant decrease in the levels of lipid peroxidation were noted’.

    Chiu et al, 2016
    https://pubs.rsc.org/en/content/articlelanding/2016/fo/c5fo01271f#!divAbstract

    ‘These in vitro observations are consistent with several clinical studies that have reported milk addition generally does not impact acute absorption of flavan-3-ols from black or green tea in humans’.

    ‘It is very unlikely that consumption of tea with or without milk will result in differences in catechin plasma concentration’.

    Van der Burg-Koorevaar et al. (2011)

    https://www.researchgate.net/publication/51237698_Effect_of_Milk_and_Brewing_Method_on_Black_Tea_Catechin_Bioaccessibility

    …a feeding study by Renouf et al.243 revealed no difference in the pharmacokinetic profiles of plasma acyl-quinic acid metabolites after drinking black coffee with or without 10% whole milk. Thus, although 5-CQA has been reported to bind to certain proteins in vitro, such as albumin and casein,244,245 milk would appear not to have a significant impact on the overall absorption of coffee acyl-quinic acids.

    However, adding a mixture of sugar and non-dairy creamer (these are traditionally made from soybean oil and lecithin) to the black coffee resulted in lower Cmax values for caffeic acid (3) and isoferulic acid (43) accompanied by longer Tmax times for ferulic acid (4) and isoferulic acid.243 Sugar246 and lipids247 are known to delay gastric emptying and this may have delayed absorption of the coffee acyl-quinic acids resulting in an extended Tmax for two of the three metabolites.

    Clifford et al, 2017

    https://pubs.rsc.org/en/content/articlehtml/2017/np/c7np00030h

    My previous post includes the 30 references which substantiate these claims.
    In the absence of a genuine and believable rebuttal from ‘nutrition facts’, it should cease immediately making this untrue claim, and remove the offending video from the net.

  21. The following covers the studies of Zhang et al, as raised by Tom

    B. Re Zhang et al, 2014

    ‘According to at least one of the papers posted by inveterate dairy promoter Pete Granger, milk clearly does impair polyphenol absorption’.

    Tom is referring to to Zhang et al, (2013). They found milk impaired absorption of jujube juice polyphenols. Jujube juice is not tea, coffee or cocoa (‘the exact mechanisms by which Z. lotus bioactive compounds exert their biological and pharmacological activities are not yet entirely elucidated’). Moreover, Zhang et al’s extensive body of research on this subject makes it abundantly clear net polyphenol bioavailability is NOT diminished by either cow or soy milk (see following).

    …. ‘when plant phenols are consumed along with food macronutrients, the bioavailability and bioactivity of polyphenols can be significantly affected. The protein–polyphenol complexes can significantly change the plasma kinetics profile but do not affect the absorption of polyphenols’

    [Table 2 demonstrates a multitude of macronutrients (not just milk) in the food matrix which may temporarily ‘change the plasma kinetics’ of polyphenol digestion, but without significantly altering their biovailability.

    Zhang et al, https://tinyurl.com/u8hvw9n

    ‘Recently, we showed that milk protein–polyphenol complexes lead to significant changes in the plasma kinetics profile but do not affect the absorption and bioactivity of polyphenols both in rats and in human subjects
    Zhang et al, 2014

    https://www.cambridge.org/core/journals/nutrition-research-reviews/article/interaction-of-plant-phenols-with-food-macronutrients-characterisation-and-nutritionalphysiological-consequences

    To reiterate Tom, according to the jujube juice researchers (Zhang et al) you are relying on ……’MILK DOES NOT AFFECT THE ABSORPTION AND BIOACTIVITY OF POLYPHENOLS’.

    Unfortunately, some (like Dr Greger) portray the outcome of pre-digestive in-vitro studies (such as Lorenz et al, 2007), as post-digestive (in-vivo) studies, whilst sidelining conflicting studies. Which delivers a completely misleading outcome.
    Zhang et al also teach us that many proteins, carbohydrates or fats temporarily diminish, delay or enhance polyphenol bioavailability. These include sugar, oatmeal, olive oil, onions, leaks, garlic, legumes, wheat, asparagus, soyabean oil, fish oil, beef and pig fat, soybeans and soy products like tofu and textured vegetable protein (genistein and daidzein), broccoli, red onions, peppers, apples, grapes, red wine, fruit juices (quercetin). See Zhang’s table 2.

    ‘As summarised in Fig. 2, proteins can reduce the in vitro antioxidant activity and significantly change the plasma kinetics profile of polyphenols without affecting the absorption. Carbohydrates can extend the time needed to reach a maximal plasma concentration. Fats can enhance the absorption and change the absorption kinetics of polyphenols’.

    Table 2, Zhang et al

    https://pdfs.semanticscholar.org/f550/22384c1c743290dcdcf1dfdcc114f786bb3b.pdf

    So, why Dr Greger’s preoccupation with just one of them, cows milk? Because it comes from an animal, not a plant ! And cows milk is the enemy.

    https://nutritionfacts.org/video/does-adding-milk-block-the-benefits-of-coffee/ .

  22. The following refer to the studies by Lorenz et al, and Felberg et al, the principal references for Dr Greger’s video on this subject: https://nutritionfacts.org/video/does-adding-milk-block-the-benefits-of-coffee/ .

    C. LORENZ ET AL, 2007

    This is the study Tom also declared: …..’and of course the study that the dairy industry and its supporters love to hate’. The study which is also Dr Greger’s principle reference for his video on the subject:

    ‘Flow-mediated dilation (FMD) was measured…. Black tea significantly improved FMD in humans compared with water, whereas addition of milk completely blunted the effects of tea …All (other) effects were completely inhibited by the addition of milk to tea. ‘

    Lorenz et al, 2007. https://academic.oup.com/eurheartj/article/28/2/219/2887513

    However, when formally challenged (criticised) by Pfeuffer and Schrezenmeir Lorenz et al subsequently conceded some extremely serious shortcomings in their study:

    ‘the increase in flow-mediated dilation (FMD) after consumption of black tea in our study was just 3.5% above the control response’

    there is ….‘further doubt whether complexes between catechins and casein, if formed at all in the intestinal tract, would remain once the caseins are broken down to amino acids and peptides. As we have shown in Table 2 of our paper, tea catechins become complexed as soon as milk is added to tea. Whether these complexes are broken down after digestion of the caseins and whether the catechins are subsequently released and absorbed later on represent interesting questions’.

    Interesting questions? More likely fundamental questions – which Dr Greger (and you Tom) had little interest in exploring !

    ‘We are also aware of the study by van het Hof et al.,6 who did not observe a difference in plasma catechin concentrations after consumption of black tea with or without milk. This objection needs to be further investigated. A plausible explanation of the fact that we observed an impairment of FMD response after addition of milk to tea may be that the catechins, owing to the longer retention period in the digestive tract, could have been modified and thus rendered physiologically inactive. The suggestion by the authors to measure the vasodilatory response at later time points is an important issue that should be addressed in future studies.’

    Lorenz et al, 2007
    https://academic.oup.com/eurheartj/article/28/10/1266/2887455.

    Lorenz et al, 2007 conceded theirs is a completely meaningless study because they had NOT (despite the claims by Dr G) established that ‘milk completely blunted the effects of tea’. Principally because they had failed to allow for delayed digestion of milk/polyphenol complexes. Not that this precludes it being quoted as gospel ever since.

    Moreover, in 2018 EFSA formally rejected the claim that polyphenols enhance FMD:

    ‘The (EFSA) Panel concludes that a cause and effect relationship has not been established between the consumption of black tea and maintenance of normal endothelium-dependent vasodilation’
    https://pubmed.ncbi.nlm.nih.gov/32625684/).

    This is not to say one shouldn’t consume black, white or green tea. It most probably provides other antioxidant-based benefits, and it is still possible there is a minor FMD benefit – particularly in the elderly. But the benefit (if it does exist) is obviously modest, and it is not diminished by the addition of milk or soy. In summary:

    1. EFSA declares enhancement of FMD by tea polyphenols is unproven.
    2. The FMD benefit claimed by Lorenz et al is minimal (just 3.5%). This compares unfavourably to about 50% improvement from *brisk walking.
    3. Due to serious shortcomings, Lorenz et al did NOT (as claimed in their study) find that milk ‘completely blunts’ polyphenol bioavailability. Repeating this claim is propagating a myth.
    4. It is impossible for added milk to ‘completely blunt’ a medicinal FMD benefit which (according to EFSA) does not even exist
    5. Up to 30 studies (see following) demonstrate that milk, and a multitude of dietary proteins, fats and carbohydrates temporarily, but not permanently diminish polyphenol bioavailability.
    6. These various studies also demonstrate there is no little or no difference between soy and cows milk in terms of their pre-digestive and post-digestive interaction with polyphenols (see following).

    * An eight-week program of brisk walking resulted in a 50% increase in brachial artery FMD in middle-aged and older men’ – https://en.wikipedia.org/wiki/Flow-mediated_dilation

    So desperate to malign milk, Dr Greger cherry-picked a redundant, meaningless and discredited study (Lorenz et al, 2007) to convey a set of false assertions. He ignored the fact that Lorenz et al had failed to make allowance for the milk-induced delayed digestion of tea polyphenols. In the circumstances, a rather unforgiveable scientific oversight. Dr Greger also bypassed up to 30 studies demonstrating milk does not diminish net polyphenol bioavailability – and in some notable instances actually increases it.

  23. Felberg et al, Dr Gregers reference for his video

    Adopting the principle that two wrongs make him right, Dr Greger endorses Felberg et al’s claims that (a) soy milk is digested differently to cows milk, and (b) unlike milk, does not blunt the FMD-lowering effect of tea polyphenols. Notwithstanding the ‘blunting’ claim had been subsequently renounced by its authors in 2007, and in 2018 EFSA advised the claimed FMD benefit was illusory. Moreover, multiple studies demonstrate that polyphenol complexes with soy milk are processed (digested) SIMILARLY to cows milk. Felberg’s study appears just as unreliable as Lorenz et al, 2007. They are employed by Brazilian Agricultural Research Corporation, and have created ‘a new soy-coffee beverage’ made from instant coffee, soymilk and sugar’. Taking their cue from the discredited Lorenz et al , 2007 study, they claim milk blunts polyphenol bioavailability. Their ‘unique selling point/product differentiation’ is that soy milk/polyphenol bindings do not. That is, unlike cows milk, their soy/polyphenol complexes are reversed during digestion. https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1745-459X.2000.00278.x Providing consumers the unexpurgated FMD-lowering benefits derived from its coffee polyphenols (notwithstanding EFSA advise it is not a FMD benefit anyway). However, multiple other studies from more commercially independent sources inform us Felberg et al’s claims are (at best) misguided. Bear in mind, the latter is a study of just 6 subjects from an organisation which has a commercial incentive to find their soy/coffee beverage has a competitive advantage over the (milk-based) opposition. Their micro-study appears more marketing promotion than research. Not that this dampens Dr Greger’s enthusiasm. Alongside Lorenz et al, 2007, its proof-positive to him that cows milk ‘completely blunts’ polyphenol bioavailability, and soy milk does not. This is a massive lowering of the bar for scientific proof. In a further distortion of the facts, Dr Greger even conjures up a pseudo-scientific explanation for soy milk’s medicinal triumph over cows milk:

    ’does it (soy milk) have the same nutrient-blocking effect (as cow milk)? No! The protein-bound chlorogenic acids that are not absorbed in the upper digestive tract seem to be released, metabolised by intestinal bacteria, and excreted in urine after absorption’.

    However, this merely describes the everyday digestive breakdown of polyphenols in the gut, as described by Del Rio et al. 2010:

    ‘in volunteers with a functioning colon these compounds (chlorogenic acid) will pass to the large intestine where they are subjected to the action of the colonic microflora’.

    ‘There is growing evidence that these compounds, which were little investigated until recently, are produced in quantity in the colon and form a key part of the bioavailability equation of flavonoids and related compounds that occur in fruits, vegetables and beverages’.

    Del Rio et al, 2010

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3257704/

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