Who Shouldn’t Eat Soy?

Who Shouldn’t Eat Soy?


“Who Shouldn’t Eat Soy?” When the Women’s Health
Initiative study found that menopausal women taking
hormone replacement therapy suffered higher rates of breast cancer,
cardiovascular disease, and overall harm, a call was made for safer alternatives. Yes, estrogen has positive effects,
the Women’s Health Initiative found, such as reducing menopausal
symptoms and improving bone health, reducing hip fracture risk,
but also negative effects: increasing the risk of blood clots
in the heart, brain, and lungs, as well as breast cancer. So ideally, to get the best of both
worlds, we’d need what’s called a selective estrogen
receptor modulator, something that has pro-estrogenic
effects in some tissues, like bone, but anti-estrogenic effects in
other tissues, like the breast. Drug companies are trying to
make them, but phytoestrogens, natural compounds in plants–
like genistein in soybeans, that are structurally
similar to estrogen– appear to function as natural selective
estrogen receptor modulators. How could something that looks like
estrogen act as an anti-estrogen? The original theory for how
soy phytoestrogens control breast cancer growth is that they
compete with our own estrogens for binding to the estrogen receptor. As you drip more and more soy
compounds on breast cancer cells in a Petri dish, less and less actual
estrogen is able to bind to them. So the estrogen-blocking
ability of phytoestrogens can help explain their anti-estrogenic
effects, but how do we then explain their pro-estrogenic effects
on other tissues like bone? How can soy have it both ways? The mystery was solved when
we discovered there are two types of estrogen receptors in the body,
and so how a target cell responds depends on which type of
estrogen receptors they have. This may be the key to understanding
the health-protective potential of soy phytoestrogens, the existence
of this newly discovered estrogen receptor–called
estrogen receptor beta, to distinguish it from the classic
estrogen receptor alpha– and unlike our body’s
own estrogen, soy phytoestrogens preferentially
bind to the beta receptors. If you have people eat about
a cup of cooked whole soybeans, within about 8 hours,
genistein levels in the blood reach about 20 to 50 nanomoles; that’s how much is circulating throughout
our body, bathing our cells. About half is bound up
to proteins in the blood, so the effective concentration
is about half that. So let’s see what that means
for estrogen receptor activation. This is the graph that explains the
mysterious health benefits of soy foods. Down around the effective levels
you’d get eating a cup of soybeans, there’s very little alpha activation,
but lots of beta activation. So now let’s look at where each of these
receptors are located in the human body. The way estrogen pills increase
the risk of fatal blood clots is by causing the liver to dump out
all these extra clotting factors. But guess what? The human liver only contains alpha
estrogen receptors, not beta receptors, and so maybe if we ate like 30 cups of
soybeans a day that could be a problem. But at the kinds of
concentrations one would get with just normal soy consumption, no wonder this is a problem with drug
estrogens, but not soy phytoestrogens. 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 10-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, but still can dramatically improve
menopausal symptoms. The Kupperman Index
is like a compilation of all 11 of the most common
menopausal symptoms. In terms of bone health, human bone
cells carry beta estrogen receptors, so we might expect soy
phytoestrogens to be protective. And indeed, they do seem to significantly
increase bone mineral density, consistent with population data
suggesting high consumption of soy products is associated
with increased bone mass. But can they prevent
bone loss over time? Soymilk was compared to a
transdermal progesterone cream. The control group lost significant
bone mineral density in their spine over the two year study period, but the
progesterone group lost significantly less and the two glasses of soymilk
a day group ended up actually better than
when they started. This is probably the most
robust study to date, comparing the soy
phytoestrogen genistein to a more traditional hormone
replacement drug regimen. In the spine, over a year, the
placebo group lost bone density, but gained in the phytoestrogen
and estrogen groups, and the same with the hip bones. The study clearly shows that the
soy phytoestrogen prevents bone loss and enhances new bone formation, in turn
producing a net gain of bone mass. But the only reason we care about bone mass
is that we want to prevent fractures. Is soy food consumption associated
with lower fracture risk? Yes. A significantly lower risk
of bone fracture associated with just a single
serving of soy a day, the equivalent of 5 to 7
grams of soy protein, or 20 to 30 milligrams
of phytoestrogens. So that’s just like
one cup of soymilk, or even better, a serving of a whole
soy foods like tempeh or edamame, or the beans themselves. We don’t have fracture data
on the soy supplements though, so if we seek the types of health benefits
we presume Asian populations get from eating whole and
traditional soy foods, maybe we should look
to eating those rather than taking unproven
protein powders or pills. Is there anyone who
should avoid soy? Well, some people have soy allergies. But a national survey found that
only about 1 in 2,000 people report a soy allergy. That is 40 times less than the most
common allergen, dairy milk, and about 10 times less than all
the other common allergens like fish, eggs, shellfish,
nuts, wheat, or peanuts.

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Comments

  1. 6:26 — Japanese eat a lot of fermented foods and sea algae… Could it be that fermented soy (natto) has different effects on the body than not fermented soy…?

  2. can somebody tell me, why I have to cough after drinking energy drinks? It maybe hast to do with blood clothing? The cough even tastes little bit like blood.

  3. theory: (you are awesome)
    A) vegan homocysteine is beneficial "IF" enough plant antioxidants are present in the diet. https://naldc.nal.usda.gov/download/28864/PDF
    B) vegan homocysteine levels are decreased by plant antioxidants "IF" enough plant antioxidants are present in the diet. https://www.ncbi.nlm.nih.gov/pubmed/12413206

  4. I dont know what it is, but i never understand a single video by him. Is it the way he arguments? Or his voice? Or is it me, im not a native english speaker…? I never have problems with english, politics, science, you name it. But this channel makes me feel stupid…

  5. Yo Doctor Greger. Are you planing on doing a video about the latest meta analysis on Milk "Milk and dairy products: good or bad for human health? An assessment of the totality of scientific evidence"
    sponsored by the dairy industry and friends

  6. I have hypothyroid disease. I've been told several things by various doctors; 1) avoid soy products or 2) take a higher dose of sythroid when consuming soy or 3) keep a 4 hour window between taking synthroid and eating soy products. Which is the best medical advice concerning soy and hypothyroid medicine?

  7. What about soy for kids (ages 2+)? Is there any truth to phytoestrogens in soy being bad for sexual development? Thank you so much for all the information. This is such an amazing resource!

  8. aushwitz diet made greger the walking dead the he is. don't follow his bs unless u wanna loose all ur hair, have the muscle density of a 12 year old and Bernie Madoff as ur friend

  9. Fibroids affect 1/5 women and is the leading cause of hysterectomies in women which can have significant long term health impacts.  Any research on affects of soy and other dietary patterns on fibroids?

  10. Ever since I've increased my soy intake I've been getting acne and what seems to be hormonal imbalance.. Is it connected? I'm trying to limit my soy intake to find out!

  11. But a 2013 study "observed lower testosterone responses following supplementation with soy protein":
    https://www.ncbi.nlm.nih.gov/pubmed/24015701

    So, shouldn't men who don't want to lower testosterone avoid soy?

  12. So what is a reasonable amount? Im eating 200grams of soy spaghetti with 1 vegan burger right now, I used one spoon of soy in my smoothie earlier. Am I overdoing it?

  13. Dr. Greger, thank you for the video, but while I am not concerned about phytoestogen, is seems soy also contains phytic acid which acts as an "anti-nutrient" (http://americannutritionassociation.org/newsletter/downside-soybean-consumption-0). Is this a major concern compared to potential benefits? And do you recommend a way to mitigate it if not? I know fermentation takes care of it but this is not always available in America.

  14. Why isn't this information more well known by doctors? I have a friend who's breast cancer is in remission but was told by her doctor to completely avoid soy. This and many other personal experiences of total incompetence and carelessness with other people's lives is why I don't trust the majority of doctors for a single second🖕🏻

  15. Soy is a rich source of omega 6. Not a good idea as our diets provide way too much omega 6 as it is. This lower omega 3 profile is a real problem to our health and drives many inflammatory conditions. Soy is a poor food choice. Not talked about on here. Think it's time to go elsewhere to get info.

  16. binge watching Nutrition videos confirms the traditional Asian diet my parents ate is so much better than today's diet.

  17. I think I have soy allergy…. ;( but I can eat tempeh with no problems. You should make a video about processed soy products and the dangers behind. I still find it hard though to understand that soy milk is okay to consume. It is also processed.

  18. Thank you Mike. I have been researching soy milk side effects recently and I am coming across a bunch of scary stuff including the blogs by Dr. Mercola telling us that soy contains aluminum particles, toxins and growth stunting chemicals. Haha. Now you are saying that soy is beneficial for us even soy milk. Thank you for this video that saves me from having to return 10 cartons of soy milk to the Dollar Tree store. I'm only drinking one carton of soy milk a day blended with fruit in blender and it tastes so great and creamy. I think that one carton a day can't prevent cell division right? Why is Dr. Mercola alarming people about soy? I am very confused. Is he paid by the meat industry? Ha.

  19. I am 54, vegan, and thank God I don't suffer from menopause simptoms at all I would say. I do skateboarding, and my bones resist pretty well the falls.

  20. Soy reduces testosterone dramatically. No wonder more and more people have no idea whether they a male or a female. Gender crap LGBTAHULnGfUakKhGGJKkK+ is a fucking hormonal hoax!!

  21. For years I have been consuming whole milk , now after being more inform and educated I'll start consuming more almond and soy milk .

  22. This is good to know since I have a genetic illness called hypermobility syndrome EDS and at the age of 26, my bone mass is already low and doctors said I’m gonna get worse and there is nothing I can do to stop it but I refuse to believe it. Yes, there is no cure for me but I believe that a healthy diet along with my strength training workouts, can help manage my health in the long run.

  23. You should have been a voice over actor. You have a cool and persuasive voice. If they ever do an animated version of the X Files, you would be perfect for Mulder.

  24. Excellent review! I eat anywhere between 250 to 500 mg of soy phytoestrogens per day, and even my multivitamin pills contain 40 mg of soy phytoestrogens. I also take probiotic pills containing the proper bacteria strains that convert daidzein into (S)-Equol (which is a metabolite of daidzein with the highest "estrogenicity" of all phytoestrogens. Indeed, I've been trying to explain this topic to mainstream anti-intellectuals and iGnorant iDiots for years now, that soy phytoestrogens are good for both men and women alike, because they're SERMs-like molecules, not actual estrogens. Mainstream thinkers however, don't understand what the hell a SERM is, so there's always that cognitive dissonance. Anyway keep up the good work.

  25. Hi Dr Greger, I cited this video in an essay for my nutrition class in community college.
    Thank you for the knowledge and expert analysis!

  26. I was just wondering does the High Levels of Magnesium contribute to the Higher Bone Densities in those who consume Soy Products? Isn't there a correlations to those who eat Mag-Rich foods?

  27. I supposedly had a soy allergy when I was tested as a kid… but I ate soy products anyway (it's in so many things) and over time I lost faith in the accuracy of the allergy test since I've never had a reaction.

  28. Dr. McDougal has a vid out that says that 40 grams of soy protein/day
    increases Insulin Life Growth factor 70%. Does Dr. Greger address this?

  29. Isn't the estrogenic effects of soy supposed to be not so good for males as it can fuck with their estrogen/testosterone balance?

  30. Thank you for that fine information. I was hoping you would address the effects of soy and breast cancer. I have read a couple of studies that said soy is an estrogen mimicker and may set women up for increased risk for breast breast cancer. I’d love to hear your thoughts on this. Thanks you.

  31. Soy is not health, it is only health when fermented and organic, but it still blocks many nutrients from entering our bodies. It needs to be fermented in order to stop this from happening.
    The soy nowadays is gm based soy. It has been formulated to stop the soy plant from dying when sprayed with weed killers. If the plant is safe, then these chemicals with do the damage.

  32. can anyone explain why dr. mcdougall is against soy products saying, "Why you might not want to consume isolated soy products! In this audio excerpt Dr John McDougall explains the connection between these soy products and increasing IGF-1 levels. When you raise your IGF-1 levels you greatly increase your risk of cancer.
    "

  33. I watched this video to see if it was good to take protein powder no gmo daily 30 grams in my breakfast, until the end of the video disappointed me.

  34. Thumbs down for click bait title. You didn't answer the question. Merely touched on it as an afterthought. You mentioned those with allergies, but not any other conditions, like hypo- or hyper- thyroid. I've "heard" those with thyroid issues should avoid soy, but it was not from people with medical or scientific backgrounds. And no doctor has addressed this question fully. Merely glossed over it. Leaving me highly dissatisfied.

  35. Hi! I am writing a paper for medical school and I really want to use the graph that was in this video from Mueller et al. However, in the original study, the graph is more complex. Did you simplify the graph yourself, or is there a place that I can obtain the simplified graph?

  36. I want to say something about the whole "soy boy" myth:

    Are you worried about "phytoestrogens?" Okay… scientists are at work on that. They'll get back to us when they have an answer. There is some evidence that too much soy can mess with your thyroid. But making you less of a man (smaller penis, mantits, etc.). Probably not.

    Even if so, many of these same people who push this "soy boy" crap seem to worry little about the REAL ESTROGEN in beef. Big Ag pumps what is essentially birth control (female hormones, estrogen) into beef and you consume it every time you eat beef, cheese, or drink milk. Real estrogen does the very thing "soy boy" pushers worry about.

    As far as we can tell, soy boys can actually have more testosterone. This may be because the beef-eaters have more estrogen in their systems than soy boys, which has an effect of cutting down testosterone. But "phytoestrogens" don't appear to have this effect. How ironic.

    For evidence, look at the study "Hormones and diet: low insulin-like growth factor-I but

    normal bioavailable androgens in vegan men," by "NE Allen, PN Appleby, GK Davey, and TJ Key," which is available on the website of the NIH.

  37. Ok. But can soy cause early puberty in girls?
    I keep hearing this rumor. I’d like to know the truth. Do you have a video about this issue?
    Thank you 😊

  38. Nowadays still a lot of popular doctors say soy is dangerous. I don't understand why there are so different points of view.

  39. I am eating vegan but had a reaction to soy milk , so had to switch to almond milk. I started getting an eczema condition that was getting worse and worse till I cut out soy milk. I wasn’t very happy about that since soy is a good source of protein. I wonder if I could get away with soy products and it’s only soy milk (no sugar added) I need to avoid 🤔

  40. soy lowers testosterone. a new breed of weak pussy soy boys are coming. fuck your soy. get your meat in and start benching.

  41. I have osteoporosis on my spine. Would a 250g serving of organic soy yoghurt improve this? The brand Sojade is an organic soy brand without any additives or added sugars, so I'm tempted to try there milk and yoghurts. Is 250g a day a safe amount?

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