T Nation

Soy & Hormonal Impact?

Happy new year coach. I’m at a retreat now where most of the protein is from tofu & bean curd…borderline vegan (though have some eggs & dairy).

I was curious what your views are on soy & tofu? I don’t seem to remember if you had commented on this much in the past…but there’s some vocal camps for (and mostly again) tofu because of its “phytonutrients” & estrogen mimicking compounds.

And then of course so called vegan bodybuilders use soy as their main protein source and seem to be doing fine.

Curious what you think. Is there a place for soy at all?


If they are “enhanced” and using anti-estrogen they can get away with it. Something to consider.

It’s not a subject of particular interest of mine because I never use such products in any of my client’s diets and none of them use them by themselves either.

I know that when I competed and was nearing the competition I once started to have huge sugar cravings and started to eat a lot of protein pudding mix… it was basically 25g of protein, 2g of fat and 2g of carbs per servings so nothing that would screw up my diet. I was taking up to 6 per day!!! After about a week I started to have itchy nipples and was holding a boatload of water. I then checked the ingredients and it was soy protein.

Will a little bit of tofu and soy have big estrogenic effects? Probably not, but the risk is there especially if large quantities are used.

IMHO if your main goal is optimizing body composition, no.

The only time I used soy products with someone focused on looking better was with a figure girl, after a contest. She stopped her period and was having vaginal dryness (sorry for the details) indicating super low estrogen. We used a small amount of soy protein and soy products for 2-3 weeks and she got her periods back.

Oh man was afraid you’d say that! Better buy a bra to cover up my bitch tits after this week (have been eating blocks, like pounds of tofu to get protein a day lol)

I’ve been enjoying soy milk for years because I love the taste… and I have yet to see any signs of high estrogen. But obviously that’s just me.

I suggest you check this out: https://examine.com/supplements/soy-isoflavones/

Edit: It also has better macros than regular milk which I like

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Yes, there is likely an individual factor at hand. I can only relate my own personal experience since I never use it with any clients and I didn’t really research it because 1) I’m a training guy first and foremost, I don’t really enjoy nutrition topics 2) even among nutrition topic, soy is one topic I really don’t care for.

BTW, just because you don’t have “obvious” symptoms doesn’t mean that there is no ill effect.

Oh there definitely IS interaction! like with everything else we eat.

Normal milk contains pure mammalian estrogen too by the way. And Geistein is 100x less effective in humans than estrogen. But the quantities are negligible.
Same goes for soy if you consume it in moderation.

Did you check the studies referenced?
VERY HIGH dosages of said chemicals in RATS.
The studies are all 18+ years old.

Not conclusive whatsoever.

I’m not defending soy at all. I have my doubts too. But opinions clearly go overboard on this topic a lot. I recommend people try it out for themselves. If they feel like they have no adverse effects, enjoy.

If you read TC original article (which i couldnt find) it showed that soy destroyed testicular cells. Also, as CT stated above, my ex wife used Estroven as a soy supplement to treat her periods and it definitely worked. Soy isoflavones are not to be messed around with.

This is a hot topic of debate in my household, where my Chinese wife insists soy is unfairly demonized and points to the myriad of fertile men in China, not to mention successful athletes brought up on the stuff. Personally I avoid all but small infrequent amounts and would never buy a protein blend or bar with it as an ingredient.

no worries gents i’ll be a n=1 guinea pig here. by the end of the week, will have consumed 4 blocks of tofu a day (7 days = 28 blocks of tofu), give or take a few. dunno how much that is.

will report on bra size

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Asians might not be as much at risk because they might have evolved genetically to tolerate soy better.

That was my rationale. I’ve heard Poliquin talk about Kashmiri folks having an amazingly high carb tolerance compared to, say, Norwegians.

Yep, my friend Borge Fagerli (who is from Norway) wrote a book about that and his all-meat diet.

Yes, I like your mate Borge but I was surprised he didn’t reference Vince Gironda and the classics steak and eggs diet - a zero carb diet predating his by several decades.

Sure, but his was a meat-only diet. Not meat and eggs. Low carbs/moderate to high fat diets are nothing new.

I’ve listened to several of his interviews and he did mention eating eggs on occasion. That said, I have huge respect for the guy and wish he would do more stuff in English!

I don’t know how much you have to eat but there is a significance to eating soy and an increase in your estrogen. If you are going to eat a lot of it, I would watch your symptoms and determine if it is changing your moods or other things.

I think there is something to say for the way people emphasize how soy crops are modified “over there” while ignoring the food practices we have here in the US. Similar to MSG - people talk about it like the devil, whereas Mountain Dew is banned in many countries.

Regarding hormones, it may be that many vegan competitive athletes take supplements to counteract the effects of increased soy consumption, I don’t really know. I can say that the people I know who have been vegan for a long time, some since the 1980’s, are doing just fine - they have procreated and have not sprouted breasts. If you don’t like soy, don’t eat it, if you do or if you don’t like meat, eat it.