Rooibos & Nettle Tea

Today's Blog--

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

Researchers recently found that human adrenal gland cells in a petri dish produce about 4 times less steroid hormones in the presence of red tea. This could certainly result in lower stress hormone levels if it happened within the body, but the effect was so dramatic the researchers were concerned it might adversely effect the production of sex steroid hormones as well. Thankfully, that’s not what they found when they tested it in human subjects. The same, however, may not be true of nettle tea.

Nettle is used to relieve the symptoms of prostate enlargement by boosting estrogen levels, but case reports show men drinking too much may grow breasts and women may actually start lactating. Nettle tea is safe as long as you 1) don’t drink too much, 2) don’t mistake it for deadly nightshade if you forage it, and 3) don’t put the leaves in your mouth fresh–they don’t call them stinging nettles for nothing! In my 3-min video Herbal Tea Update: Rooibos & Nettle I show a close-up of the impalement of a nettle spicule in the skin.

My go-to herbal tea is hibiscus (see my last article Hibiscus Tea: The Best Beverage?). But nettle tea is touted for being packed with minerals. That always seemed a bit strange to me. 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 you just steep some tea? We never knew because it hadn’t been tested, until now.

Researchers compared the mineral content of nettle tea to chamomile tea, mint tea, St. John’s Wort, and sage. If you watch the video you’ll see that nettle tea didn’t seem to have much more than any of the others, but maybe they’re all really high?

One cup of nettle tea has the same amount of iron as dried apricot, the zinc found in a single pumpkin seed, one-twentieth of a mushroom’s worth of copper, and 4 peanuts’ worth of magnesium and a fig’s worth of calcium. I agree with the researchers that a cup of herbal tea may not be an important source of minerals, but it’s not negligible. Greens are so packed with nutrition that we can benefit by just drinking some hot water they’ve been soaking in for a few minutes.

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 otherwise consuming the cooking water. See Best Cooking Method for more tips on preserving nutrients.

-Michael Greger, M.D.

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Image credit: chumsdock / Flickr

  • VegAtHeart

    Is there a scientific basis for us to be concerned about antinutrients in any of these teas that you describe?

  • Fern Glen

    Thanks for these most interesting articles. I do appreciate getting them in article form as I don’t always have time to listen to a video.

  • Darryl
    • nc54

      Would it be a good idea to have both, hibiscus and rooibos, at the same time?

      • Darryl

        There is no study suggesting synergy, though other studies have found synergies from other Nrf2 inducing food compounds. I was just pointing out that when one understands the mechanism of how plant xenobiotic compounds activate endogenous stress responses, often through Nrf2-ARE, one sees it everywhere. There’s probably a Nobel Prize for Kaymin Chan or Jed Fahey for discovering Nrf2 and its modulation by phytochemicals.

  • mykamakiri

    Any more updates on yerba mate, anyone?

  • TeaDrinker

    What about dandelion tea?

  • David

    Forgive me if this has already been asked, but would we receive any additional benefits (other than fiber) if we were to eat the tea leaves after steeping them? Is there a reason why tea leaves are typically not consumed after they are steeped?

    • Thea

      David: You may want to research “matcha”, which if I understand correctly is a green tea prepared in such a way that the tea leaves themselves *are* consumed.

      For normal green tea, I believe that the tea leaves are not usually consumed due to texture issues. However, in one of Dr. Greger’s videos, he describes throwing a handful of white tea leaves into his morning smoothie. So, people (at least our Dr Greger anyway) do consume the tea leaves, though not always part of the drink.

      As to, additional benefits: I would guess that the following is true: While a lot of nutrients seep out of the leaves while soaking in water, you don’t necessarily get all of the nutrients. So, yes, if you eat the entire leaf, then you get even more benefit than from just drinking filtered tea water. (not counting stinging nettle of course if it is going to sting one’s tongue)

      For my own opinion, eating those leaves by themselves would not be appetizing. So, if I were going to do it, I’d want to put them into a smoothie, muffin, or oatmeal or something. Just an idea.

      That’s my 2 cents. Hope that helps.

    • Darryl

      For green tea, some of the “antioxidant” polyphenols like EGCG with ample benefits don’t elute into the liquid. And while tea leaves are high in polyamines (which may have intriguing anti-antinflammatory, cardiovascular-health, bone-health and anti-aging properties), almost none of them enter solution.

      • Thea

        Darryl: Thanks for supplying the specifics.

  • Ben

    Dear Dr. Greger,

    Your comments about Rooibos tea are are very interesting! I have just one question: As you say that there’s a risk of fluoride-poisoning from over-dosing on green tea, I’d like to know what is the limit on Rooibos tea as well, since I’ve read that it’s rich in fluoride, maybe more than true tea! Do you have any information about it?


  • Is one cup of nettle tea a day going to significantly lower my testosterone levels? I drink a store-bought variety that comes in a teabag and is a mixture of roots and leaves dried. I do a lot of weight-training, and I’d rather cut down on anything that would impact that and also the other consequences of low testosterone.