Do Vitamin D Supplements Reduce the Risk of Dying from Cancer?

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Vitamin D Supplements for Reducing Cancer Mortality

It all started with a famous study entitled “Do sunlight and vitamin D reduce the likelihood of colon cancer?” that was published in 1980. Johns Hopkins University researchers were trying to figure out why states like New Mexico and Arizona have only about half the colon cancer rates of states like New York, New Hampshire, and Vermont. Could it be because New Mexicans and Arizonans get so much more sun? The researchers proposed that perhaps vitamin D, known as the sunshine vitamin, is a protective factor against colon cancer. Since then, sun exposure has also been associated with lower rates of 14 other types of cancer.

As I discuss in my video Do Vitamin D Supplements Reduce the Risk of Dying from Cancer?, vitamin D may also affect cancer survival. Higher blood levels of vitamin D were associated with lower mortality of patients with colorectal cancer. How much lower? Nearly half the mortality. And, the higher the vitamin D levels, the lower the death rate appeared to fall. This may explain why the survival rate from colon cancer may depend in part “on the season of diagnosis.” The risk of rapid death is lowest if you’re diagnosed in the fall after you’ve spent the summer building up your vitamin D stores. Other risk factors could be seasonal, too. For example, perhaps people are taking advantage of the fall harvest and eating healthier, which might explain lower risk in the autumn. Additionally, “[a]lcohol intake is a risk factor and may be highest in the winter season…” What about physical activity? In the summer, we may be more likely to be outside running around, not only getting more sun, but also getting more exercise, which may itself be protective.

These kinds of studies just provide circumstantial evidence. Establishing a cause-and-effect relationship between colon cancer and vitamin D deficiency using observational studies is challenging because of confounding factors, such as exercise habits—so-called lurking variables. For example, there may be a tight correlation between ice cream sales and drowning deaths, but that doesn’t mean ice cream causes drowning. A more likely explanation is that there is a lurking third variable, like hot weather in summertime, that explains why drowning deaths are highest when ice cream consumption is also at its highest.

This actually happened with hormone replacement therapy. Women taking drugs like Premarin appeared to have 50 percent less risk of heart disease, so doctors prescribed it to women by the millions. But, if we dig a little deeper into the data, we find that, indeed, women taking estrogen had 50 percent lower risk of dying from heart disease, but they also had a 50 percent lower risk of dying from accidents and homicide, so it probably wasn’t the drug. The only way to know for sure is to put it to the test in a randomized, clinical trial, where half the women are given the drug and we see what happens. A decade later, such a study was done. Instead of having a 50 percent drop in risk, within a year of being given the hormone pills, heart attack and death rates shot up 50 percent. In retrospect, the lurking variable was likely socioeconomic class. Poor women are less likely to be prescribed hormone replacement therapy and more likely to be murdered and die of heart disease. Because of the lurking variable, a drug we now know to be dangerous had initially appeared to be protective.

Besides lurking variables, there’s also the possibility of reverse causation. Perhaps low vitamin D levels didn’t worsen the cancer. Instead, maybe the cancer worsened the vitamin D levels. This may be unlikely, since tumors don’t appear to directly affect vitamin D levels, but cancer treatment might. Even simple knee surgery can cause vitamin D levels to drop dramatically within hours, thought to be due simply to the inflammatory insult of cutting into someone. So, maybe that could help explain the link between lower vitamin D and lower survival. And, cancer patients may be spending less time running around the beach. So, yes: Higher vitamin D levels are associated with improved survival in colorectal cancer, and the same has been found for breast cancer. In fact, there is about double the risk of breast cancer recurrence and death in women with the lowest vitamin D levels. What’s more, higher vitamin D levels are associated with longer survival with ovarian cancer, as well as having better outcomes for other cancers like lymphoma. But, the bottom-line, as we learned with hormone replacement, is that we have to put it to the test. There weren’t a lot of randomized controlled trials on vitamin D supplements and cancer, however…until now.

We now have a few randomized controlled trials, and vitamin D supplements do indeed appear to reduce the risk of dying from cancer! What dose? Researchers suggest getting blood levels up to at least about 75 nanomoles per liter. These levels are not reached by as many as three-quarters of women with breast cancer nor achieved by a striking 97 percent of colon cancer patients .

Getting up to these kinds of levels—75 or, perhaps even better, 100 nanomoles—might require about 2000 to 4000 IU of vitamin D a day, levels of intake for which there appear to be no credible evidence of harm. Regardless of what the exact level is, the findings of these kinds of studies may have a profound influence on future cancer treatment.

What about just getting sun instead? Be sure to check out my six-part video series:

It’s better, of course, to prevent colon cancer in the first place. See, for example:

For more on that extraordinary story about Premarin and hormone replacement therapy, see How Did Doctors Not Know About the Risks of Hormone Therapy?

In health,
Michael Greger, M.D.

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


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.

90 responses to “Vitamin D Supplements for Reducing Cancer Mortality

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  1. Okay, speaking of cancer, some of us are curious if the vegan women in England still have more breast cancer and if the Adventist women do and if you still explain it as vegan woman often don’t have children?


    You are the one I started following and that shocking old video is where I started. Right now, most of the WFPB doctors are anti-supplement and the cancer rates and Vitamin D is a topic I challenged vegsource on, so did England have an improvement and is that because the women got preggers? Or did global warming cause England to have more sunshine? Or was the BBC writer a misogynist and missed a few categories with the misses?

    1. Did the BBC miss things restated to their #1 and 2 cause of death, and decided that a rare type of stroke was more interesting? Or did the rates change?

  2. I am not convinced by the above article that D supplements are useful for everyone. I am still reading the studies linked. If the evidence was positive re lowering incidence of cancer in the first place that would be different.
    It would be interesting to see trials about just ‘running around ourside’ in reducing incidence of disease.

      1. Barb,

        I felt so differently. I wouldn’t necessarily have even thought there would be a reduced cancer incidence in 2 to 7 years, but I was blown away that they found significantly reduced total cancer mortality. Fewer deaths when you already have cancer seems extraordinary to me.

  3. Vitamin D and sulforaphane act synergistically to prevent colon cancer. They act on the Wnt signaling pathway. Lee et al. Journal of Nature and Science, Nutrition, vol 1
    pg 1, 2015.

  4. Thanks for the great article. So helpful.
    Q) When in the day is the best time to take a Vitiamin D supplement? Early morning, mid day or night before bed? And lastly is it best absorbed by taking or eating something else with it?

    Thanks again, love your work

      1. The Washington Post says to take any fat-soluble vitamins with foods that contain some fat. That makes it with a meal or snack, so that makes it “Not at bedtime.”

    1. Hello Terance, thanks for your comment.

      It’s best to take your vitamin D with the biggest meal of the day, usually at lunch, when we also have plant-based fats (like avocado) which can help us to increase the vitamin D absorption.

      Hope it helps.

  5. 4000 iu of vitamin D has not put me near the sweet spot mentioned. I wonder what would make my body require so much more to arrive at that ideal number. Getting a lot of sun brings its own problems. I used to be a sun worshiper in my younger years and did a lot of gardening in the summer sun in later years and now have the mottled skin to prove it. D levels did not rise to the occasion even then.

    1. Lola,

      There are things like being older, being overweight, having darker skin and just not going out in the sun enough all affect it.

      I have some mottled skin from the sun, too. I think of it whenever I see the skin damage commercial on television. I burn easily and my face in particular always turned red, rather than tan.

      Dr. Greger said that he was taking 5000 while he was writing, “How Not to Diet” because he considered himself to be closer to what an institutionalized person’s levels would be.

    1. “There was a suggestive 17% reduction in cancer deaths, which became a 25% reduction in analyses that excluded the first two years of follow-up.”

    2. Konrad,

      African Americans, who were the group who was most likely to actually be deficient DID have a decrease risk of getting cancer by 23%. To me, that is even more proof that supplementing rather than being deficient might actually lower peoples’ risk of cancer. Particularly if they are obese, dark-skinned, elderly, or don’t go outside in the sun.

      Plus, there was a reduction in DEATH from cancer up to 25% and THAT should count.

      However, there was a suggestive 17% reduction in cancer deaths, which became a 25% reduction in analyses that excluded the first two years of follow-up.

      1. Mentally, I wonder about confounding factors with the Vitamin D issues.

        For instance, one study presents a decrease of homocysteine and ferritin in response to regular training supported by vitamin D supplementation, and other studies showed an inverse relationship between D and homocysteine but only if the people were low in D.

        Okay, so in a study, those who are low in D might have their homocysteine levels drop and that might affect all sorts of disease risks, but those who are out in the sun and already have enough Vitamin D will not show any effect at all.

        Or confounded another way, Vitamin D supplementation lowers risks in African Americans, but maybe not in vegan African Americans who are already WFPB or maybe not in African Americans who eat lots of processed meat all day long.

        I don’t know if I am explaining it properly, but if WFPB improves the condition so much, but there are conditions like Alzheimer’s which also need the Homocysteine to be low, and some people even in this community didn’t get theirs to drop, it might not show up in a study, but that doesn’t mean that it didn’t prevent that group from getting Alzheimer’s.

        That is the reason we need so many parts of it put to a test.

        I don’t feel like most of the WFPB community even acknowledges that improving mortality is already pretty good and they don’t acknowledge that the African American part might be something, which could potentially be duplicated in the other high-risk factor group.

          1. Here is the sentence which I can post next to #1.

            Recent advances have proven that there is a close link between hyperhomocystinuria and cancer (see Fig. 1). First, higher levels of plasma homocysteine have been observed cancer patients, and venous thromboembolism (VTE) is the second most common cause of death in cancer patients.

            1. #2 might be the microenvironment and things like inflammation.


              Does decreasing inflammation help with cancer? The microenvironment study seems to think so.


              When I looked it up, some of the markers for inflammation, one, for example, had 6 studies where it helped and 4 studies where it didn’t. I don’t trust the people who decide to throw out the 6 positive studies. They don’t do a process which I can follow and figure out whether they took everything into account.

              I know that Dr. Fuhrman mentioned there were studies with ridiculously high and low doses didn’t help and where some studies used D2.

              1. I compare it to the shocking vegan study, if nobody looks for mechanisms the answer would have just been increases breast cancer, doubles the rate of Alzheimer’s and no real benefit for much of anything else.

                It would have just been a deceptive answer and without these doctors’ that would have been the answer.

                1. One of the inflammation markers which it improved sometimes was Interleukin 6 and that was one of the mechanisms which some researchers targeted for cancer.

                  Mechanisms like that might only help some cancers.

                  I just feel like science is just starting to understand mechanisms.

                  Homocysteine is one that helps me understand that we could learn more and more and more, but miss everything.

                  Doctors are saying not to take these supplements.

                  1. Or the inverse, in some ways Colin saying just eat Whole would be the movement, but most people aren’t perfect at it and it doesn’t account for B12 or D3 or Omega 3 and that vegan having no benefits has to happen all the time.

                    There has not been a study where deficiency was proven to not matter as long as you have enough decades WFPB.

  6. Frequent testing of my vitamin D levels showed that supplementing with 5000 IU of D3 daily was still insufficient to bring my level up to 75 nano moles per liter. I need to take 10,000 IU per day (5000 2X per day) to get my level to 77.2 nano moles per liter. It is critical to have blood levels checked and adjust daily dose accordingly. That’s the only way to know for sure if your supplementation is proper/adequate. BTW, I get plenty of daily sunshine while riding my bicycle 6-7K miles per year so sun exposure is not a good or reliable guide.

    1. Hi Tom,
      Dr G. speaks of Vit. D levels in units of nano moles per liter. When I have my levels checked by Labcorp they reports the number in units of nano grams per deciliter. Do you know how to convert between the two? I have seen that 30 ng / dL is about the same as 75 nmol / L.

        1. Tom.
          I test my level the same way at Labcorp. Dr. G. in the above blog suggests a level of 75 to 100 nanomoles. That is equivalent to about 30 to 40 nanograms. 77.2 ng is equivalent to 190 – 200 nanomoles.

          I’m not an expert so I don’t know if that is good or bad. I know if I take 5,000 IU of vitamin D my level increases from about 32 to 50. I would probably have to take 10,000 IU, like you, to get up to 77.2 ng.

  7. This is one of the topics that makes me wish that Drs. Greger and McDougall would get together and that I could ask them “Which one of you is ‘nuts’? Whose nutritional knowledge is ‘kinda flax’? and Who got a ‘D’ in vitamin supplementation?” Tough to know where to go when 2 guys you respect seem to disagree (McD does not recommend D supplementation).

    1. Completely agree. But I tend to side with Dr. McDougall. Reading the post above, “Frequent testing of my vitamin D levels showed that supplementing with 5000 IU of D3 daily was still insufficient to bring my level up to 75 nano moles per liter.” makes me question the rationality of these huge supplement doses. How did people survive for so many millions of years without supplement?

      1. Blair,

        Can I ask if you would take it if you were African America and it would lower your risk of cancer by 23% and death by cancer by 25%?

        What if you were obese or were in a situation where you didn’t get sunlight?

        I look at the statistics and wonder if Dr. McDougall inwardly says, “What good is 25% fewer cancer deaths? Nah, if you were black, you might not get cancer 23% that isn’t good enough to even try. Might as well just stay deficient.”

        But I know that he was from California and is out doing things like skiing with his grandchildren and he isn’t worried about his Vitamin D levels. Heck, he is thin and white and lived in a good sunlight part of the world and has been eating WFPB all these decades. Not gonna worry about it.

        1. I like Dr. McDougall, but find him to be almost flip about Vitamin D.

          I read the studies and the children in northern Europe are deficient in the Winter and the children in Iceland are already deficient in September.

          Those are kids. The vast majority of people in America are overweight or obese. The thin doctors just make fun of them and don’t give them wisdom. The dark-skinned communities are not even hearing that they could have a benefit because the white doctors are so anti-supplement that they skip over those lines. The elderly community in America is growing steadily and many of them become house or institution-bound and they are already confused enough without doctors being able to tell them that they are more likely to be deficient and that it might not be okay to stay that way.

          1. Vitamin D Supplementation: No Benefits Shown in Recent Studies

            • Vitamin D pills were not shown to help prevent heart attacks or cancer: A study led by a Harvard researcher, Dr. Joanne Manson, followed 25,871 men and women for a median of 5.3 years. Participants who took vitamin D3 (cholecalciferol), 2000 IU per day, had no added protection from heart diseases or cancers (NEJM, November 10, 2018).


            1. We could go study by study because it can help with things, which affect cancer.

              How about Metabolic syndrome?

              How is this study?

              Metabolic syndrome has emerged as a major public health concern, affecting 30% to 60% of postmenopausal women worldwide. The progression of abdominal obesity and heart disease that lead to metabolic syndrome increases significantly as women age and appears to be directly associated with estrogen loss in postmenopausal women. This has led some researchers to recommend estradiol treatment for women who are fewer than 6 years postmenopausal as a means of preventing heart disease.

              Similarly, vitamin D has been associated with several markers of metabolic syndrome, including obesity, hyperglycemia, insulin resistance, and type 2 diabetes mellitus. Supplementation with vitamin D has been shown to reduce the risk of metabolic syndrome over a 20-year follow-up.

              Because the synergistic benefits of vitamin D and estrogen are already documented to improve bone health in women, researchers in this newest study from China hypothesized that the same interaction might affect metabolic syndrome. The cross-sectional study included 616 postmenopausal women aged 49 to 86 years who were not taking estrogen and vitamin D/calcium supplements at the beginning of the trial. It concluded there was a positive correlation between vitamin D and estradiol.

              Specifically, higher vitamin D was associated with a favorable lipid profile, blood pressure, and glucose level. Estradiol was negatively associated with cholesterol, triglycerides, and blood pressure. These results suggest a synergistic role of vitamin D and estradiol deficiency in developing metabolic syndrome in postmenopausal women.

              Findings are published in the article “The synergistic effects of vitamin D and estradiol deficiency on metabolic syndrome in Chinese postmenopausal women.”

              “In this cross-sectional study, low estradiol increased the risk of metabolic syndrome in postmenopausal women who had vitamin D deficiency,” says Dr. JoAnn Pinkerton, NAMS executive director. “The Endocrine Society recommends vitamin D levels of 30 ng/mL for postmenopausal women. Whether adequate levels of vitamin D improve nonskeletal cardiovascular or cognitive benefits remains the subject of debate, and answers await randomized clinical trial data.”


                The randomized, controlled, clinical trial involved 218 women with insufficient vitamin D levels at the beginning of the study. Half of the women were randomly selected to a weight loss program plus daily vitamin D, and half received a weight loss regimen plus a dummy pill, or placebo.

                At the end of the year-long study, the researchers found that those in the vitamin D group whose blood levels of the nutrient rose the highest – from inadequate at baseline to normal, or replete levels – had a corresponding drop in circulating estrogens and other sex hormones that are a known risk factor for breast cancer. The reduction in sex hormones among the women with the highest levels of vitamin D was observed even after taking into account how much weight the women lost, showing that the vitamin D had an independent effect on hormone levels, regardless of pounds shed.

                1. The thing is vegan women have higher rates of Breast Cancer in the study.

                  Are the white, thin, male doctors rolling the dice with the vast majority of women?

                  1. Okay, how about the males?

                    Well, in several studies it lowered Interleukin 6. That is listed as a mechanism in prostate cancer. Is it possible that SOME types of cancers are helped and some aren’t and that the studies are inconsistent because of which cancers are expressed?


                    Although numerous studies have implicated vitamin D in preventing prostate cancer, the underlying mechanism(s) remains unclear. Using normal human prostatic epithelial cells, we examined the role of mitogen-activated protein kinase phosphatase 5 (MKP5) in mediating cancer preventive activities of vitamin D. Up-regulation of MKP5 mRNA by 1,25-dihydroxyvitamin-D3 (1,25D) was dependent on the vitamin D receptor. We also identified a putative positive vitamin D response element within the MKP5 promoter that associated with the vitamin D receptor following 1,25D treatment. MKP5 dephosphorylates/inactivates the stress-activated protein kinase p38. Treatment of prostate cells with 1,25D inhibited p38 phosphorylation, and MKP5 small interfering RNA blocked this effect. Activation of p38 and downstream production of interleukin 6 (IL-6) are proinflammatory. Inflammation and IL-6 overexpression have been implicated in the initiation and progression of prostate cancer. 1,25D pretreatment inhibited both UV- and tumor necrosis factor alpha-stimulated IL-6 production in normal cells via p38 inhibition. Consistent with inhibition of p38, 1,25D decreased UV-stimulated IL-6 mRNA stabilization. The ability of 1,25D to up-regulate MKP5 was maintained in primary prostatic adenocarcinoma cells but was absent in metastases-derived prostate cancer cell lines. The inability of 1,25D to regulate MKP5 in the metastasis-derived cancer cells suggests there may be selective pressure to eliminate key tumor suppressor functions of vitamin D during cancer progression. These studies reveal MKP5 as a mediator of p38 inactivation and decreased IL-6 expression by 1,25D in primary prostatic cultures of normal and adenocarcinoma cells, implicating decreased prostatic inflammation as a potential mechanism for prostate cancer prevention by 1,25D.

        1. Blair,

          The Vital study, from what I see, the black community is the one who if they supplemented they were less likely to get cancer. Everybody else, if they supplemented they were less likely to die of cancer.

          Just saying.

          The whole point is that there is logic for Dr. Greger’s position.

          Those agencies might be taking counsel from someone like Dr. McDougall, but he says sentences like “People in Boston can just go outside for 5 minutes and just get some sunlight on their face and that is enough.” and I already know that I live in an area where it was too cold to do that in the Winter and older people are told not to go out in the cold without their faces covered. It is too hot in the Winter and older people are told not to go outside in extreme heat and my sister-in-law’s mother was the one who got heat stroke this year, but there always is one. It is dark in the fall and it was overcast or raining every single day of the Spring up until June 21st and then turned 90 the next day where I live.

          I would have ZERO Vitamin D if I listened to Dr. McDougall.

          1. Plus, Dr. Greger and Dr. McDougall BOTH recommend the same dose of D3 and that is based on studies and they aren’t telling people to go extremely high dose.

            Last time this topic came up, I went to ever Vitamin D study I could find and I agree with Dr. Greger.

            The Vital Study made me agree with him even more.

            1. I say all that and will add that I seriously respect Dr. McDougall and I do agree with his stance on many supplements. I watched his folic acid video and if I didn’t eat foods with folate, I would be taking seriously low doses of the supplement.

              I don’t find that he allows for obesity, weather conditions, dark-skin and also things like respiratory problems, and pain and things like Alzheimer’s also had positive studies.

              By not dealing with “is it okay to stay deficient?” I feel like the vast majority of Americans who are overweight or the dark-skinned community or the fact that even kids don’t go outside – in some areas for safety. Many people are incarcerated and will the prisons listen to Dr. McDougall and not give the African Americans who spend 23 hours per day in solitary confinement Vitamin D? How about the mental health community? The supplementing study that I saw said that their cognitive abilities improved with supplementing, even if their psychoses didn’t improve. Is having cognitive levels improve worth anything or do we do a “Nah, they are still having psychoses, so maybe it is better for them to not have cognitive improvements?”

              1. Let’s do the people who cannot ever go in the sun, those conditions are becoming more common.

                Do you feel confident that they can not supplement at all?

                1. But even if everybody magically became ideal weight white people with enough leisure time and mobility to have sunlight and even if all the prison doors flew open and institutions just let all the patients wander outside and if parents felt safe enough to let their kids just go outside and play and the internet wasn’t distracting it away from happening….

                  Then, 23% less likely to die from the cancer which is already floating around in everybody’s body (Dr. McDougall did a good video and it is already in there) sounds pretty good to me.

                  1. For depression, there was a study with adolescents that low Vitamin D status correlated with depression and supplementing Vitamin D improved it.


                    In psychoses, people who were racially more likely to have psychoses had that “race risk” disappear when Vitamin D deficiency was looked into.

                    A Finland study showed that supplementing D vitamins lowered the risk of children growing up to become schizophrenics and in Sweden, there was a study where there was a lower rate of psychotic-like symptoms with increasing vitamin D intake.

                    Yes, sometimes other studies do contradict, but there are more than enough positive studies on supplementing Vitamin D for me.

                    I do know that I am having fewer psychotic episodes. None, in fact.

                    7 years ago was a non-stop psychotic episode.

                    I guess I just feel like WFPB only preaches to WFPB in this case.

          2. I doubt if the VITAL study presents a strong case for supplementation. Yes, if you break it down into increasingly smaller groups, apparent benefits emerge in some subgroups but is that just random chance – a consequence of the Law of Small Numbers?

            Let’s not forget that VITAL also showed all-cause mortality in the vitamin D supplement group cauwas the same as all-cause mortality in the placebo group.

            All cause mortaility in the omrgsa 3 supplement group was actually higher than in the placebo group.

            According to the American College of Cardiology

            ‘The results of this trial indicate that supplementation with either n–3 fatty acid at a dose of 1 g/day or vitamin D3 at a dose of 2000 IU/day was not effective for primary prevention of CV or cancer events among healthy middle-aged men and women over 5 years of follow-up. This is one of the largest trials on this topic. The finding of a lower MI risk with n–3 fatty acid is hypothesis generating and deserves further study. The authors also noted some interaction with baseline fish consumption, with greater CV benefit observed among participants who had low fish intake at baseline.’

          3. I doubt if the VITAL study presents a strong case for supplementation. Yes, if you break it down into increasingly smaller groups, apparent benefits emerge in some subgroups but is that just random chance – a consequence of the Law of Small Numbers?

            Let’s not forget that VITAL also showed all-cause mortality in the vitamin D supplement group was the same as all-cause mortality in the placebo group.

            All cause mortality in the omega 3 supplement group was actually slightly higher than in the placebo group.

            According to the American College of Cardiology

            ‘The results of this trial indicate that supplementation with either n–3 fatty acid at a dose of 1 g/day or vitamin D3 at a dose of 2000 IU/day was not effective for primary prevention of CV or cancer events among healthy middle-aged men and women over 5 years of follow-up. This is one of the largest trials on this topic. The finding of a lower MI risk with n–3 fatty acid is hypothesis generating and deserves further study. The authors also noted some
            interaction with baseline fish consumption, with greater CV benefit observed among

            1. There were factors though.

              Statistically fewer deaths from cancer, particularly when they tested for proportionality over time.

              More significant to me was when they said that BMI may have modified the effect of vitamin D on cancer, where if they separated out the normal-weight people, the effect was greater. I hadn’t read that last time, but I had speculated about it.

              The black community had a statistical benefit. Obese people had less of a benefit than normal-weight people, but they might not have received enough is one possibility.

              1. So, are all of you in agreement that the black community accidentally had lower cancer incidence on top of 25% lower mortality, but that was accidental, so they shouldn’t ever find out.

                And the obese people, it didn’t work, so they might as well stay deficient, rather than try more to see if they can get any to stay out of their fats?

                I feel like that is the consensus.

        2. Personally Blair, I believe that the less we ‘mess with things’ the better off we are. There is no way D3 pills capture the processes initiated by the effect of the sun upon tne skin. (like that wonderful coq10 vid Dr Greger did).
          I make a point of being outside everyday, in all weather, sun or not because I do benefit, if only to de-stress.

      1. Yes, but vegsource believes that it is okay to be symptomatically deficient.

        There have been people here who were symptomatically deficient and, for instance, for women, it can help with estrogen and homocysteine and science has not solved for the real risks associated with being postmenopausal and there are enough sources that it helps with the things I am trying to accomplish that I don’t understand why not to take it when even the vital study had an improvement in mortality and if black people can prevent cancer, maybe it would help other nationalities.

  8. Each person obviously juggles health concerns, priorities, life circumstances that are unique to him or her. It goes without saying that we all make the best decisions for ourselves at the time as we can according to our varying needs.

    1. Barb,

      That is the truth.

      For one thing, the studies for things like Vitamin D supplements are not just on people who are deficient, so those of us who have had maybe 30 minutes in the direct sunlight total over the past 3 years altogether have to decide whether it is important to get any or not.

      My brain is better supplementing and I have seen enough mortality bump in studies to choose that having some Vitamin D in my system is the way to go.

      I have seen positive studies in things like supplementing D with pain and with respiratory and there are DNA studies so that already is enough reason to take it.

      1. Deb (or anyone knowledgeable) — I have a wheelchair-bound (and housebound) friend of 79 years who often get no direct sunlight (esp. in Winter), but she does sit by a south-facing patio window which gives her plenty of sunlight through the pane of glass.

        Does the glass cut out most of the UVs or whatever stimulates skin to produce D?

        1. Slainte,

          Windows do block the UV.

          I wondered if I could sit out in the car with the air conditioning and technically, I was able to do it, but honestly, the late morning and early afternoon are my busiest times and even after finding that concept, it only actually happened once.

  9. I didn’t know where to post this but I’ve been on the plant based diet for 2 months. My cholesterol was so high my doctor told me I can either take a statin or go on a plant based diet. I went on the plant based diet for 2 months and just got my lab results and my doctor told me my numbers are great and to keep doing what I’m doing! I’m so excited. My total cholesterol was 266 and it’s now down to 215, but my HDL is 103, my ldl went from 152 to 109 and my non HDL went from 162 to 124! I’m just so excited I wanted to share and thank you all for your blogs and Dr. Greger for this website. My doctor told me to go on this site to get information and I ordered the book “How Not to Die” and made all the recipes. I just love the recipes! I stopped eating fish, chicken, dairy and protein bars and shakes and started eating everything Dr. Greger suggested. I never used to eat fruit because of “sugars” and what I thought to be extra calories. I eat so much fiber now. I sauté everything in organic vegetable stock. I’ve never eaten so much food before! And my weight never went up! So thank you all. I just wanted to share. I’m so fortunate my doctor suggested this instead of putting my on medication! I come across so many unhealthy people who don’t want to change their diet and they prefer to take a pill. Sad. I just hope my numbers continue to go lower. I’m 56 and love to exercise and eat healthy (I thought I ate healthy until this website), so I’m optimistic. Information – solid facts – is key to good nutrition and I’m thankful this site has that. I wish you all continued good health and happiness!

    1. Congratulations! Welcome aboard. We were vegan for 15 years but ate a pretty crappy, Americanized vegan diet. Discovered the WFPB diet 4 years ago and it completely transformed us. Another excellent book is “The Starch Solution” by Dr. John McDougall. Good luck.

      1. Thank you, Blair and Deb. And I will look at “The Starch Solution”. My brother is on statins and he, and many others, told me the high cholesterol in the family is hereditary and to just take a pill. Everyone would give me such a hard time when I was at our Country Club and I would slip out of my purse a beet burger made from The “How Not To Die” cookbook and put it on a salad and just ask for apple cider vinegar on the side. I would have one handy when going to a restaurant just in case I couldn’t find something plant based. Although most restaurants are accommodating. I just smiled and ignored the remarks. It’s all good. I kept thinking “if this doesn’t work…” !! I read different opinions on olive oil (not to use or some use) and almond flour (to use of not) – avocado oil, coconut oil, so I’ve just stayed away from it. If you have any thoughts…

        1. ” I read different opinions on olive oil (not to use or some use) and almond flour (to use of not) – avocado oil, coconut oil, so I’ve just stayed away from it. If you have any thoughts…”
          Yes I do. Oil (and refined sugar) are not whole plant foods. All our great nutrition doctors, Greger, McDougall, Ornish, Klaper, Barnard, Popper, Davis, Esselstyn, etc recommend a whole foods, plant based diet. WFPB. And less processing is better. So, for example, eating cooked wheat would be better than eating bread baked from whole wheat flour.

    2. Diane, congratulations!! Your success is inspiring and comes to me at a moment that helps. I also thought I ate quite healthily. After 27 years of restless legs syndrome (labeled “severe” in two sleep lab visits), I was increasingly desperate for something after having tried every method and trick known to humankind. I discovered WFPB eating last Christmas and have been slouching towards it since.

      Beating my carb addiction is tough, and with an ADD mind it’s challenging to do the daily & weekly food prep consistently, but I’m making some progress over the past 9 months in getting back my life, though not nearly as dramatically as you. I’m off all meat and diary and sugar and down to about two eggs per week, and am working on getting a diet with a lot more leafy greens and legumes, etc. I woke up this morning after another in a countless stream of bad night of sleep fighting discouragement yet again, so your story is welcome.

      I appreciate NF both for the evidence-based articles by Greger & staff but also for the wonderful comment threads such as this one with their mix of additional science and stories of success. Thanks.

      1. Slainte,
        I enjoyed reading this post. You write so well and I loved your use of the word “slouching” as you described your move toward WFPB.

        L’Chaim! (To life)

      2. You only think you are slouching.

        You are doing great!

        Adding in the greens and legumes will help with the lowering the other things.

        As far as the eggs go, are you doing omelets or using them in recipes?

        I recommend finding a good tofu scramble recipe. Actually, High Carb Hannah has one and it includes the “trick” for making the dish taste eggy.

        If you are using them in baking, learning about how to make flax eggs is also on YouTube.

      3. Slainte,

        Thank you for your comments. Very thoughtful. You certainly made my day by how nicely you shared. I hope my story encourages you to move forward. I’ve heard restless leg syndrome can be just awful. I’ve been fighting with severe leg cramps at night. You shouldn’t be so hard on yourself! Any progress is good progress! So good for you. I agree with Deb. You are doing great! And Deb, I just finished watching some videos on High Carb Hannah and I thought they were great. I just made her “yogurt” out of soy milk and probiotics and will see how it tastes tomorrow after it sits for 24 hours. And I love her recipe on banana “ice cream”. Slainte, I ate egg white omelettes at least 3-4 times a week so am looking forward to trying the tofu scramble. I hope you give it a try too.

      4. Slainte,

        I used to eat 2 eggs a week; now, I eat 2 servings of beans a week for breakfast instead. I still have a small piece of toast (I make my own sourdough whole grain bread, but there are other options), with almond butter or jelly. So, I have eggs WITH toast (not the British eggs ON toast).

        I cook my beans in an Instant Pot, and freeze portions for later. But you could use canned beans, which is what I suggest to my busy daughter.

        I also use Dr. Greger’s Daily Dozen app for guidance; it’s very helpful, with links to al kinds of information.

        Happy eating!

    3. Totally agree. Vitamin D deficiency has multiple detrimental effects on our physical and mental health. Everyone is different and have differing lifestyles.
      We tend not to fish, semi-naked in clean water, for a good portion of our diet being healthy uncontaminated oily fish anymore!
      I have recently discovered my levels were low.. have supplemented and within weeks my mood has improved, hair appears healthier, nails are stronger etc.. things I can currently observe, regardless of what may be improving internally.

      1. Ruth,

        That is what I bear witness to.

        I have improved in so many little ways taking it. Including brain health and I came here off of a brain breakdown and I have stopped having psychotic episodes and I am not sure which supplement or food helped, but I have done each of them on and off and going off Vitamin D, I started getting moodier and more anxiety.

        I didn’t have as extreme brain problems as when I had B12 insufficiency symptoms because with that, the night terrors and hallucinations started coming back.

        But because I don’t like spending money on supplements, and because I forget to take them for weeks at a time, I have cycled on and off all of them individually.

        My brain is so much better on them.

        I am working on my house and what I do know is that I have such a broken brain and I am post-menopausal and Vitamin D is something which helps post-menopausal women. Plus, I never had children, partly because of having come from abuse. I got past it emotionally for myself but didn’t have a sense of being able to bring children into the world. I thought I would get all the way past it, but I didn’t until I was past child-bearing age (though technically, someone just had a baby in her old age is what my coworker’s sports radio announcer said.)

        So, my mother died of breast cancer and I am at higher risk from never having had children, plus, I am at higher risk of Alzheimer’s from that, and the scientists haven’t solved that at all and vegans get Alzheimer’s twice as often and I didn’t lose much weight going WFPB and have cancer and Alzheimer’s in my family and Vitamin D helps with Homocysteine and inflammatory markers (in half of the studies) and I do not trust Vegsource to begin with.

        And I highly, highly, highly respect Dr. McDougall, but he is even backing up about B12 and I got my hallucinations back with the B12 insufficiency symptoms and don’t know how he can say that when people’s spines melt in the first place.

        He seems a little paranoid about every single supplement and I mean that in the nicest way.

        Some of us spent so much time in psychoses when I first started having the brain problems that I understand paranoid pretty well from the inside now. Though it is hard to not be paranoid in our modern culture.

        I just do understand Dr. McDougall’s logic for many of the supplements and I hit like on all of those videos, but I feel like I have done all of the simple things to lower my Homocysteine and B12, Vitamin D, and Omega 3 are easy peasy.

        1. Deb, re: vegans get Alzheimers twice as often

          Did you see that in a study somewhere ? If you can find it, please post it. Dr Greger has written atricles that tell a different story. In this article he explains that vegetarians/vegans have a smaller risk of Alzheimers.

          Also, be sure to read Dr Mirkin’s short post on vit D for some points to keep in mind. Just as an aside, for me, hair, nails and mood specifically all fluctuated for months at a time along with thyroid hormone levels. Now that my thyroid meds are adjusted, there is a huge difference in these things, and sleep quality too.

          1. Barb,

            That was from the study from England years ago.

            It isn’t contradictory. Vegans who didn’t deal with Homocysteine and with their Omega 6/3 ratio had zero benefit and had twice the rate of Alzheimer’s and more Breast Cancer. I already have higher risk of both of those and yet I followed his logic and do believe that fixing things like Homocysteine and going off of oil and making sure I get enough Omega 3 and Vitamin D that I will be able to lower those risks.

            Here is his talk from back then. The beginning is about the study, which I think is the same study which finally is showing vegetarians and vegans having some benefits, but they had more hemorrhagic stroke risk and the vegan community is debunking it, but it is only Dr. Greger’s voice I want to hear. Is it a situation such as Homocysteine and Oil or is it an over-adjusted study. I do believe Dr. Barnard when he says that egg eaters have a 41% increased risk and they are high saturated fat and sodium as a whole group. Nobody is mentioning whether the other factors other than heart and ischemic stroke improved. I want to hear about whether they improved in Alzheimer’s and Breast Cancer and intuitively, I think they must have, because the BBC didn’t mention those and Cancer and Alzheimer’s are #1 and #2 on the death list Dr. Greger showed when he did “How Not to Die” in the UK.

            It means a lot to me because I am a post-menopausal woman who never had children and that increases my risk of both of those conditions and possibly so did going vegan, but I do believe that I am lowering my Homocysteine and my dietary cancer risk factors, but post-menopausal women don’t always have the same benefits as other people for many of these studies and I have to do my own math, because people don’t mention it.

            I go back to the fact that black people may lower their cancer rates by supplementing Vitamin D, but none of the doctors, other than Dr. Greger will even tell them. I find that to be irresponsible. It should be mentioned and the black community should make up their own minds, but the WFPB community has become anti-supplement, but the supplements were how I am trying to reverse the risk of being in the twice the Alzheimer’s rate and higher Breast Cancer rate.

            Yes, WFPB may have totally different risk rates and Dr. Ornish’s study will be coming out, but in the meantime, I have to make decisions and I would feel safer in the logic if there was more agreement within the community. I want someone to evaluate that recent England study and tell me if any other rates changed other than heart disease and whether hemorrhagic stroke changed from last time or if it was just not mentioned because there were so many other bad answers back then.

            Here is Dr. Greger back then.


            1. I guess I realize now that I am not going to lose weight probably. I will look at “How Not to Diet” and see if there is anything. I don’t think anything is going to help now. I didn’t know that until today, but I pretty much do know it now.

              I also realize that Vitamin D might not help me because of that and that I am at work and it is 3 in the morning and I have gotten 20 to 30 minutes of direct sunlight in the past years altogether and still don’t sleep.

              I have a friend who I am not even going to talk about Whole Food Plant-Based with. I think it is too late for her and her body is having so many allergic reactions to plant foods now. It might have been easier when she could eat them.

    1. Eva,

      Here is the link Dr. Greger quoted about Vitamin D and survival with cancer.

      The Vital study only found that it prevented cancer in African Americans in the study, but it improved mortality in people who already had cancer by 17 to 25%.

      Improving mortality seems pretty worth it to me. It also might help with pain levels and depression, so there might be other differences.

  10. Vitamin D Supplementation: No Benefits Shown in Recent Studies

    • Vitamin D pills were not shown to help prevent heart attacks or cancer: A study led by a Harvard researcher, Dr. Joanne Manson, followed 25,871 men and women for a median of 5.3 years. Participants who took vitamin D3 (cholecalciferol), 2000 IU per day, had no added protection from heart diseases or cancers (NEJM, November 10, 2018).

  11. Tried to post link but couldn’t. Here’s a brand new Vitamin D study –

    Study Warns Too Much Vitamin D May Actually *Decrease* Bone Density

    CALGARY, Alberta — Everybody needs some vitamin D to help absorb calcium and build healthy, strong bones, but are people overdoing it with vitamin D supplements? That’s the question posed by University of Calgary researchers who say too much vitamin D can actually be detrimental to bone health.

    Just 10-15 minutes spent in the sun while wearing a bathing suit is enough for our bodies to produce all the vitamin D we will need for the day. However, many people who live in areas with sparse access to sunlight in the winter months, such as Canada, end up taking vitamin D supplements every day to get their daily dose.

    While it’s generally not a bad idea to take vitamin D supplements, there are often conflicting guidelines for just how much vitamin D a person should be ingesting on a daily basis. Furthermore, researchers theorized that some Canadians may be taking up to 20 times the amount of vitamin D their body needs because they are dealing with any one of a variety of medical conditions that might be related to a lack of vitamin D.

    All of these factors lead the research team to pose the question: How much vitamin D is too much?

    “Although vitamin D may be involved in regulating many of the body’s systems, it is the skeleton that is most clearly affected by vitamin D deficiency,” says Dr. David Hanley, one of the principal investigators of the study, in a media release. “Current Health Canada recommendations were set to prevent the bone diseases caused by vitamin D deficiency for the vast majority of healthy Canadians. But it has been more difficult to clearly establish the optimal dose of vitamin D. When we designed this study, there remained a question whether there’s more benefit in taking a higher dose.”

    After conducting a three-year study, researchers concluded that there are no health benefits to taking high doses of vitamin D. A total of 300 volunteers between the ages of 55-70 were analyzed, and the research team’s hypothesis was that higher doses of vitamin D would result in stronger and denser bones among participants. The volunteers were split into three groups; one group received 400 IU (international units) of vitamin D per day, the second group received 4,000 IU per day, and the third group received 10,000 IU per day.

    For reference, Health Canada recommends Canadian adults under the age of 70 only intake around 600 IU of vitamin D per day, while Osteoporosis Canada recommends that Canadian adults at risk of developing osteoporosis take up to 2,000 IU per day.

    Each volunteer had their bone strength and density measured using traditional dual x-rays (DXA), as well as with a new state-of-the-art computed tomography device called an XtremeCT. This new device allowed researchers to examine participants’ bones in greater detail than could have been imagined even a few years ago. Each volunteer was scanned at the beginning of the study, and then again after 6, 12, 24, and 36 months. Vitamin D and calcium levels were also measured via blood and urine samples collected throughout the study.

    Researchers took the data collected from the traditional dual x-rays and the XtremeCT device and calculated two different versions of each participant’s bone mineral density (BMD). BMD is the amount of calcium and other minerals found in a particular bone segment.

    It’s normal for humans to lose some bone density as we age, and according to the traditional dual x-rays’ findings all three dosage groups displayed a gradual decrease in BMD over the course of the three years. However, the more advanced Xtreme CT device picked up much more pronounced differences in BMD loss among the three dosage groups.

    According to the XtremeCT readings, volunteers in the 400 IU group lost 1.4% of their BMD over three years, the 4,000 IU group lost 2.6%, and the 10,000 IU group lost 3.6%. These results were in direct contrast to what researchers expected to find; higher doses of vitamin D seemed to cause a decrease in bone density, not an increase.

    “We weren’t surprised that using DXA we found no difference among the treatment arms, whereas with XtremeCT, the latest in bone imaging technology, we were able to find dose-dependent changes over the three years. However, we were surprised to find that instead of bone gain with higher doses, the group with the highest dose lost bone the fastest,” says professor Steve Boyd, one of the study’s principal investigators. “That amount of bone loss with 10,000 IU daily is not enough to risk a fracture over a three-year period, but our findings suggest that for healthy adults, vitamin D doses at levels recommended by Osteoporosis Canada (400-2000 IU daily) are adequate for bone health.”

    Researchers also noted that volunteers within the 4,000 and 10,000 IU groups exhibited an elevated risk of developing hypercalciuria, or high levels of calcium in one’s urine. Hypercalciuria is often associated with the development of kidney stones.

    “What we can see in this study is that large doses of vitamin D don’t come with a benefit to the skeleton,” concludes co-author Dr. Emma Billington. “For healthy adults, 400 IU daily is a reasonable dose. Doses of 4,000 IU or higher are not recommended for the majority of individuals.”

    The study is published in the Journal of the American Medical Association.

  12. No-one is deficient in Vitamin D pills, only in sunlight exposure and the two are not nearly equal… sure the pills are almost certainly better than nothing but the clinical results of D3 pills have not stacked up well. Sunlight also produces nitric oxide and many other beneficial factors. We were not created to live in a cave all our days..

  13. Someone may have already commented on this, but in Phoenix people tend to stay indoors during the summer except for fools like me. I must be English (Mad Dogs and Englishmen are out in the noonday sun). Ergo our Vitamin D levels fall during the summer and depression rates appear to climb then as well.

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