Herbal Tea Update: Rooibos & Nettle

Herbal Tea Update: Rooibos & Nettle
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Rooibos (red) tea may reduce stress levels by suppressing adrenal gland function. Nettle tea is mineral-rich, but may have estrogenic side effects.

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Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Rooibos, or red tea, is anecdotally reported to aid stress-related symptoms, but has none of the mood-altering phytonutrients thought responsible for the increased calm and decreased stress after drinking green tea. So, why do some people feel less stressed drinking red tea?

Well, researchers recently found human adrenal gland cells in a petri dish produce about four times fewer steroid hormones in the presence of red tea. Yes, this could quite possibly contribute to “the alleviation of negative effects arising from elevated [stress hormone levels]” if it actually damped down adrenal function that much in real life. But, the effect was so dramatic they became concerned it might adversely effect the production of sex hormones, as well. But, that’s not what they found when they tested it in “human test subjects.”

The same may not be true, however, of nettle tea. Nettle is used to relieve symptoms of prostate enlargement by boosting estrogen levels. But, men drinking too much may grow breasts, and women may start lactating. Nettles are often picked wild, so there’s always a risk that someone might accidentally pick something like this, instead of this, and come down with atropine poisoning, because the nettle tea you thought you were drinking had some belladonna (deadly nightshade). Also, not a good idea to put the leaves in your mouth fresh. They don’t call them stinging nettles for nothing. This is a close-up of the impalement of a nettle spicule in the skin—not something you want in your tongue.

Nettle tea is touted for its high mineral content, which always seemed kind of strange to me. I mean, yes, if you boil dark green leafy vegetables long enough, you do lose minerals into the cooking water. But, how many minerals could we be getting if we just steep some tea? We never knew, because it hadn’t been tested—until now.

They compared the mineral content of nettle tea to chamomile tea, mint tea, St. John’s wort, and sage. Nettle tea didn’t seem to have much more than any of the others—but, maybe they’re all really high? Well, one cup of nettle tea does have the iron of a dried apricot (that’s more than I expected), the zinc found in one pumpkin seed, one-twentieth of a mushroom’s worth of copper—but four peanuts’ worth of magnesium, and an entire fig’s worth of calcium.

I agree with the researchers that, you know, a cup of herbal tea may not be an important source of minerals, but it’s not negligible. You know, greens are so packed with nutrition that you can benefit from just drinking some hot water they’ve been soaking in for a few minutes.

Please consider volunteering to help out on the site.

Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.

Rooibos, or red tea, is anecdotally reported to aid stress-related symptoms, but has none of the mood-altering phytonutrients thought responsible for the increased calm and decreased stress after drinking green tea. So, why do some people feel less stressed drinking red tea?

Well, researchers recently found human adrenal gland cells in a petri dish produce about four times fewer steroid hormones in the presence of red tea. Yes, this could quite possibly contribute to “the alleviation of negative effects arising from elevated [stress hormone levels]” if it actually damped down adrenal function that much in real life. But, the effect was so dramatic they became concerned it might adversely effect the production of sex hormones, as well. But, that’s not what they found when they tested it in “human test subjects.”

The same may not be true, however, of nettle tea. Nettle is used to relieve symptoms of prostate enlargement by boosting estrogen levels. But, men drinking too much may grow breasts, and women may start lactating. Nettles are often picked wild, so there’s always a risk that someone might accidentally pick something like this, instead of this, and come down with atropine poisoning, because the nettle tea you thought you were drinking had some belladonna (deadly nightshade). Also, not a good idea to put the leaves in your mouth fresh. They don’t call them stinging nettles for nothing. This is a close-up of the impalement of a nettle spicule in the skin—not something you want in your tongue.

Nettle tea is touted for its high mineral content, which always seemed kind of strange to me. I mean, yes, if you boil dark green leafy vegetables long enough, you do lose minerals into the cooking water. But, how many minerals could we be getting if we just steep some tea? We never knew, because it hadn’t been tested—until now.

They compared the mineral content of nettle tea to chamomile tea, mint tea, St. John’s wort, and sage. Nettle tea didn’t seem to have much more than any of the others—but, maybe they’re all really high? Well, one cup of nettle tea does have the iron of a dried apricot (that’s more than I expected), the zinc found in one pumpkin seed, one-twentieth of a mushroom’s worth of copper—but four peanuts’ worth of magnesium, and an entire fig’s worth of calcium.

I agree with the researchers that, you know, a cup of herbal tea may not be an important source of minerals, but it’s not negligible. You know, greens are so packed with nutrition that you can benefit from just drinking some hot water they’ve been soaking in for a few minutes.

Please consider volunteering to help out on the site.

Images thanks to Jorge RimblasTom EllisF. D. RichardsLeslie SeatonJaBB, and Katherine via flickr; and RichardelainechambersSimrandeepTheornamentalist, and Benedikt.Seidl via Wikimedia

Doctor's Note

I’m sorry this video had to be cut at the last minute from my volume 12 Latest in Nutrition DVD—I ran out of room!

My go-to herbal tea is hibiscus. See my previous video, Herbal Tea Update: Hibiscus, and my earlier video, Better Than Green Tea? Mint would also be an excellent choice: Antioxidants in a Pinch.

That micrograph of the nettle spicule made me think of the Migrating Fish Bones video—I think I’d take the nettles any day!

The fact that so much nutrition leaches into the water in nettle tea is a reason we don’t want to boil greens, unless we’re making soup or something where we’re consuming the cooking water. See Best Cooking Method for more tips on preserving nutrients.

Also, for more context, be sure to check out my associated blog post: Rooibos & Nettle Tea.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

52 responses to “Herbal Tea Update: Rooibos & Nettle

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  1. Good morning Dr Greger,

    Update! My sisters cardiologist agreed to work with her going vegan as an alternative to the angiogram and stint. As you would expect he said, “but that’s really hard to do.”

    Thanks again for giving my sister the needed encouragement.

    1. What’s to hard…? Cracking open and pulling apart the chest, which is next, of flooding the kitchen countertops and fridge with fruits and veggies, so the choice is evident? Carl Esselsteyn MD has achieved amazing results with putting all his patients on veg lifestyle. If you need help, go to PETA’s website and see if cruelty wil be convincing. It make take your whole being to make the switch, but it’s only for your WELL being.

    2. Veganrunner: Thanks for the update. The cardiologist may not be fully educated or 100% on-board, but it sounds like a good start. Better than other doctors out there. Good luck to your sister!

    1. i’m not so sure–a friend reported this morning that the lectures, Dr. Greger’s annual summaries of nutrition research are no longer on YouTube.

  2. In the video Herbal Tea Update: Rooibos & Nettle. Nettle leaf is the concern but is nettle roots (as it is given to man with prostate problem) the same action???

  3. My Grandmother’s caregiver is from the Philippines and mentioned Guyabano fruit, saying that it is antibacterial, anti inflammatory and inhibits cancer cell growth. The fruit is expensive and a little hard to find. Was wondering if the tea offered health benefits.

    1. Nearly every plant has anti-bacterial, anti-fungal, anti-viral, anti-pathogen, anti-inflammatory, anti-cancer activity.
      Besides exotic and expensive ones, check out all those available at your local grocer.

  4. I brag about this website so much, my friends made me a refrigerator magnet that says “WWMGE?” (What would Michael Greger eat).

  5. Im curious how the different infusions are made? Im talking about V1, H2 and K2? Assuming they are different types of infusions and not just same method done three times… Might as well make it the most powerfull way if I’m gonna get some minerals from it :)

  6. Dr. Greger,
    Could you do some investigating on nettle leaf tea for allergies? It is concerning that this type of tea might have estrogenic effects. thanks!

    1. Olive oil is absolutely fine. You don’t need to worry about its caloric content if you are not overweight and not overeating or gaining weight. It has a higher omega-3 content than many other vegetable oils too, which is great on a vegan diet.

      1. Using 1-2 tablespoons/daily of any oil – depends on your health goals and health status. Why use any oil? Oil not only adds calories but is a source of inflammation therefore it wanting to avoid/arrest/reverse heart disease – the less oil the better.

  7. Good Morning Dr. Greger,
    I live in Columbia, Marylalnd area. I am looking for Doctors who practice or are open to preventive health care using diet for CAD/ Heart disease. I have read Dr. Esselstyn/ Dr. Dean Ornish Prevent & Reverse Heart Disease. I have read their books and am changing my diet to reap the benefits. I have many questions. Please Help me find doctors in this area that I can work with.
    Ann H.

    1. I would also check with the Physicians Committee for Responsible Medicine in Washington DC to see if they have members in the Columbia area who might be able to help. Your health plan may be able to help either through the internet (when I worked at Kaiser Permanente I had a website which provided information about my interest in working with patients on a whole food plant based diet) or member services. Good luck.

    2. Neil Barnard has a new medical clinic in Washington, DC. I believe it’s called the Barnard Medical Center, and it opened late 2015/early 2016.

  8. Good Afternoon, Dr. Greger,
    As a woman of 34 with Addison’s Disease (Adrenal Insufficiency), I’m concluding that based on this research, I should avoid drinking Rooibos Tea and other red teas. Would you agree, and if so do you have any further recommendations regarding adrenal support through nutrition.
    After considering your evidence to support Hibiscus tea, I’ve been drinking it daily. One tea bag a bedtime in a Nalgene bottle of water in the fridge, and enjoy it in the morning. Our kids prefer I dilute their apple juice by 50% with mixed berry zinger, as opposed to just using water.
    Thank you for supporting my families health with good, solid research.
    May your tribe increase.
    Amy,
    Washington State

  9. How quickly do you have to drink the ice tea before antioxidants start to decrease or do they not decrease?

  10. The trouble with many scientific studies of medicinal plants is that they pay little or no attention to the traditional methods of gathering and steeping different teas for different purposes. Tests are run for nutritional values based on improper steeping methods.

    Nettles are supposed to be gathered in the Spring before flowering, steeped for four to eight hours a dry leaf-to-water ratio of one dry ounce of leaves (about 1-1/4C) per quart of water.

    Any word on the nutritional content of nettles gathered and steeped properly?

    1. Great points, Tracy Taub! After listening to the video, I’ve been thinking along those same lines. I truly would love to see more research on the topic of traditional herbalism, where the studies are set up and done properly, based on traditional methods, like you mentioned above. : )

  11. I had breast cancer in 2006, now i am very healthy, and i like to drink tea, and recently i bought rooibos tea, but someone told me theat its not good for people who had breast cancer. Is that true Dr Greger ?

  12. I would be most interested to see a report on B17/amygdalin/laetrile/apricot pits.

    This book seemed pretty convincing to me:

    World Without Cancer: The Story of Vitamin B17
    by G. Edward Griffin (Author)

    Thanks for your great service!

    1. Hi foodman999. Thanks for reposting your question. I did a search, as I recall another member talking about apricot pits for cancer treatments and this vitamin B17 arose from discussion. I would take serous caution here. Just don’t think the science is there. This is old but relevant review discussing the lack evidence for vitamin B17. If I hear of more info or I see more data I will surely reconsider.

      Thanks!
      Joseph

  13. Uh, you don’t get Nettles confused with other plants in the wild. One might when looking at photographs, but there’s a really really easy way to “test” your selection in the wild. ANY adventuresome (not always on the manicured park and trails type) who has recreated near a river or stream in short pants in this part of the world well knows the signature sensation of nettles stinging his/her legs. And yes I’ve eaten the green leaves raw. It’s all about the technique and selecting the youngest leaves from the plant. A bit of a sting won’t kill you, ask me how i know.

    1. Wade: My sentiments, exactly! There are also applications for harnessing the power of the sting of stinging nettles, such as beating some of the leaves on arthritic joints, which worked for me. I’m hoping that someone finds some research on long-steeped nettle infusions, to tease out fact from fiction.

  14. I’m a big fan, Dr. G! I’m also a big fan of herbal infusions (long steeped) for some herbs, as opposed to just herbal teas (short steeped). Are there any studies on these kinds of herbal infusions, a la Susun Weed, that you know of? Try making an infusion of nettles and you’ll see the difference in concentration and, I would believe, nutrients.

  15. I believe I maybe suffering from an adrenal hormone imblance, as I’m suffering with a few symptoms such as Tired all the time, massive energy slump through the day, regular feelings of weakness, craving of foods, hard to get up in the morning. Is there anything in particular that is recommended to help with this please? It’s been happening since May of this year, and the energy slump during the day is absolutely ridiculous. Come to around half three to four, and I could literally sleep immediately

    1. Hi, Daniel John Peters. I am Christine, a NF volunteer. First, if you have not done so already, you should check with your doctor to be sure there is not a medical issue causing your symptoms. Assuming that all is well otherwise, there are several things to consider. Did something in your life change around the time your symptoms appeared? Do you get enough sleep at night? Are you exercising regularly? Are you eating a wide variety of whole plant foods? Addressing stress, sleep, and nutrition could make a difference. I hope that helps!

      1. Hi Christine,

        Nothing major happened in my life at the time. In fact I had just come back from holiday. My diet is pretty much whole food based, with the odd vegan sausage or burger thrown in ever couple of weeks. I have pretty much eliminated sugar from my diet and I do exercise regularly. Either gym or Brazilian Jiu-Jitsu around three to four times a week. Sleep is at times not great, sometimes I wake up and am like that for hours in the middle of the night. I had a blood test at the Dr’s and that came back about as normal as it could be, only slightly low on Vitamin D.
        I find my workouts, have at times, become harder than before, and that middle of the afternoon or early evening I literally cannot hold my eyes open and sleep very heavy for around thirty minutes to an hour. Reading through The Ultimate Nutrition Bible, Patrick Holford suggests my original concern could be the root cause. Now, I understand reading a book to having a test done is massively different, yet this is something that is of great concern for me,As since switching to a plant based diet, which has been relatively solid for the most part, has great impact on people, and at the moment I feel I am suffering. Any advice would gratefully received

        1. I assume you that after your holiday, you were following the same diet as before. I don’t know where you went, nor what you ate while you were away. It is possible you have some kind of low-grade infection acquired during your travels that could be affecting you. I trust you have addressed the vitamin D issue. If you have not, I would start there. There are some high-quality plant-sourced vitamin D supplements on the market. My best advice is still to see your doctor to rule out a medical cause for your symptoms. Improving your sleep should also help. These videos might be useful to you:
          http://nutritionfacts.org/?fwp_search=sleep&fwp_content_type=video
          I hope that helps!

          1. Thank you, I’ll have a browse through that. I’ll have another check up as soon as I can.
            I went to Iceland and managed to eat well out there, as I cooked some of my food. I did eat a fair bit of sugar when I was there though. My Vitamin D was only marginally under the “Norm” and all others were exactly where they hoped for my age.

            Thank you for the reply

            1. Daniel, the extra sugar could be a factor. Extra sugar may affect insulin response, and can dramatically affect the composition of the gut flora. This can have wide-ranging effects on health. Try taking Saccharomyces boulardii as directed on the package. Jarrow makes a veggie cap. You may find that it helps to rebalance the gut flora. Some pau d’arco tea might also help. If you don’t mind, post back here to let us know how it goes for you.

    2. I have exactly the same symptoms.

      It’s been almost 5 years now. I’ve been to a lot of doctors, functional medicine doctors, natural paths, endocrinologists, rheumatologists, etc

      I am on thyroid medication. That has helped somewhat, but I still got that midday urge to fall asleep.

      It would be nice to find an answer to this, as I have spent a good bit of the last five years bed ridden.

  16. Regarding nettles, I find them rather tasty. When I can get them fresh, I make soup with them (when they’re cooked, they don’t sting anymore), so I get all the minerals and whatever else they have to offer. When dry, I infuse them for a long time, sometimes for hours and drink it through the day. I don’t do this everyday, but oncee in a while.

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