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.

Images thanks to Jorge Rimblas, Tom Ellis, F. D. Richards, Leslie Seaton, JaBB, and Katherine via flickr; and Richardelainechambers, Simrandeep, Theornamentalist, and Benedikt.Seidl via Wikimedia

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 Rimblas, Tom Ellis, F. D. Richards, Leslie Seaton, JaBB, and Katherine via flickr; and Richardelainechambers, Simrandeep, Theornamentalist, and Benedikt.Seidl via Wikimedia

Nota del Doctor

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.

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.

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