The Truth About Soy

I’m kind of confused. Ninety percent of this article seems to be a well written and sited indictment of the effect of soy on human health and hormone levels.
“The Bottom” line is by contrast an equivocal throw-your-hands-up-in-the-air “well, don’t worry it all depends.”

1 Like

The RCT’s which have the strongest design either show no change or small changes in group averages. My focus is more on the outliers which sometimes show more substantial changes. Of course, looking at outliers in controlled studies risks turning them into case reports but nonetheless it can be useful.

The main question is why there are these discrepancies in some studies and I think the most obvious explanation is the difference in pharmacokinetics (isoflavone levels in plasma can very several hundred to over a thousand fold difference between individuals) and pharmacodynamics. But even so, if we accept that as the reason we have to further explain why it doesn’t show up so readily in various studies. I think that’s also due to the dose required.

The, “well, it depends” answer isn’t as satisfying but it applies to a lot of potential adverse effects of various compounds.

The T.H. Chan school of public health? Yeah… I wouldn’t trust that to be a reputable source of health advice for soy.

They also think that seed oils are good for you and that you shouldn’t take aspirin.

Harvard has incredibly debased themselves over the years.

People get confused because of Industry Funded Research. Soy is a big industry and it doesn’t take much money at all to request a report with a positive spin. Same deal with basically al research, it’s a shame but it’s reality.

A lot of women think they are immune to soy, that they have estrogen anyway so it doesn’t matter. But look at the incidence of terrible diseases such as endometriosis and breast cancer in modern times.

1 Like

This article from harvard site doesn’t bring anything meaningful to the discussion. I have no idea why you even put it here. If you are providing it here, at least elaborate why do you think it has any kind of relevance and/or connection with the content of the article you are commenting.

Here is a meta-analysis paper from 2021 showing that soy intake does not adversely affect male hormones.

Thanks for your reply. I posted this in response to another question. This paper is a meta-analysis of research to date in 2021 that shows that soy does no affect male hormones.
I agree that more research could be necessary but it is important to know that a good portion of the anti-soy information that has been circulating for >20 years was generated by non-scientist quacks at the Weston A Price Foundation.

1 Like

From the article:

Declaration of Competing Interest

“Mark Messina has a conflict of interest. Dr. Messina regularly consults for companies that manufacture and/or sell soy products. Mindy Kurzer is on the scientific advisory board of the Soy Nutrition Institute.”


Does not seem to be a non-biased study. So they didn’t receive funding for this specific study but both lead authors have a direct financial interest in promoting soy based product.

I am of the opinion we still don’t know but it doesn’t seem that whey or Caesin affects test/estrogen levels so why take the chance?

1 Like

Whoa, calm down dude! Your Soy Diet-Induced Estrogen is off the charts!

Refer to 1st reply below for my thoughts on this post being flagged.

I wish they’d included women in this study because anecdotally, estrogenic substances cause a 5.2% increase in thigh-binding blobulin.

1 Like

lol who was so offended by me that they felt it necessary to report this comment? Was it @heath_watts by chance? The same dude that posted:

Question about this meta analysis you keep posting: Do you think the authors may have been incentivized to promote soy based products based on their financial stakes in the Soy Industry?

1 Like

Meta-analyses can be very useful but they aren’t particularly helpful in identifying a specific change if the majority of studies utilized aren’t likely going to be relevant for a particular question. For example, if the vast majority of studies utilize a dose of 65 mg or less, yet you suspect negative effects upon testosterone levels may begin over 100 mg, the pooling of data isn’t going to be very helpful to answer the question. In this case, Reed et al. readily note their limitations in the discussion section. In fact, they discuss equol, androgen receptor expression and decreased testosterone in studies utilizing doses of 100 mg or more.


I’d ask if you even lift, but if you’re shown in the photo, I know you don’t.

Did this sound smarter in your head? zoom in a bit so you can see my tiny muscles

1 Like

heath_watts presented a peer-reviewed article that challenges your notion of soy.
All you offered was snide remarks. Could we please maintain some civility here?
If we have nothing positive to say, then perhaps we should leave it unsaid.

Great article Mr. Wilson. I especially enjoyed your objective approach.
I feel isoflavones can be used as a SERM

As noted above by @cyclonengineer:
“Mark Messina has a conflict of interest. Dr. Messina regularly consults for companies that manufacture and/or sell soy products. Mindy Kurzer is on the scientific advisory board of the Soy Nutrition Institute.”

He wouldn’t respond to my question, then went on the be the Soy Defender by telling me i don’t look like i lift. This man (@heath_watts) is also at least 51 years old acting like this, but you’re right - I’m the one in the wrong here for cracking a joke.

Let’s not forget he came out swinging: accosted T Nation and accused them of being funded by the dairy industry…then goes on to post a fairly recent paper published by folks who acknowledged in the paper that they have a serious stake in the success of the soy industry…

Seems a bit Harvey Dent.

1 Like

Thank you! Glad you enjoyed it. And I agree completely. The data are much stronger to support ER-beta agonism at more reasonable doses (e.g., 1 mg/kg isoflavones–0.25 to 0.75 mg/kg genistein in particular) while effects upon hormone levels likely require at least 1.5 to 2 mg/kg before small effects are seen and likely in only some individuals.

Andrewgen_Receptors I apologize for the delay in replying, as I log in sporadically. You bring up a valid point regarding conflicts of interest, which can indicate bias. However, that is not always a good rule of thumb. A decent meta analysis gathers relevant reference materials using filters that are (or should be) annotated in the paper. The pertinent data (with references) is presented to validate their thesis question(s). It is a intensive process that can easily take months to crank out.
So a researcher may need to garner whatever supporter they can for funding, often with the stipulation that the sponsor needs to accept whatever results the investigation finds.

We need to examine all the papers to enhance our skills separating the chaff from the grain. Too much unsponsored research is conducted primarily for getting published and as a bonus, eliciting an emotional response in media to spread their names across the country. While often well written, most the results are trash.

Back to your question, I do not know what financial interests they have with the soy market. Though I do feel soy has gotten a bad rap in the body building community, which I find incongruent with the sport. Having your ER filled with a weaker estrogen analogue than E2 is the basis of most SERMs.

Then there are the anticarcinogenic benefits. There are strong correlations that soy reduces breast and prostate cancers. Lots of papers on it. A friend says large amounts of soy keeps his BPH in check.

I believe heath_watts was being serious and wasn’t in the mood for kidding around. I am often that way on the forums, so I (usually) try to keep my big yap shut. Especially with the new people too lazy to search the forums or Google, let alone get some education under their belt. Thank you for the serious response back.

1 Like