Questioning the estrogencity of soy lecithin


Continuing the discussion from The Real Problems With Soylent Are Not Fixed In Version 1.1:

I finally had time to read the study, and I don’t think it’s as strong or clear as these quotes from the abstract imply.

As always, the usual caveat applies that a single study can only IMPLY something, not conclude it… and so far, this is the only study I know of finding an estrogenic effect from soy lecithin.

They were apparently the first to use the YES method (genetically engineered yeast with human genes in them) to evaluate the estrogenicty of soy lecithin, because they note that they could find no standard extraction method in the literature, (they decided to extract with acetone.) They weren’t able to find any known estrogenic soy isoflavone in the extract, but they did see the GMO yeast react as if there were an estrogenic comound, prompting them to speculate, “a so-far unidentified estrogenlike compound is present in soy lecithin. Whether this chemical is of soy origin or is a contamination during production remains to be answered.”

I’d like to see confirmational studies, perhaps using a different extraction method or discussing/confirming the validity of the method, confirming that this is not a false positive from the yeast (always a risk with a reaction to an “unknown.”), and I’d like to see different soy lecithin sources - they did not use a commercial food lecithin source, but rather, two different brands soy lecithin sold as supplements that they picked up on a spur of the moment in “local drug stores.” Lastly, I’d like to see this done with other, non-soy lecithin sources - sunflower lecithin, chicken yolk or other animal lecithin. If soy lecithin is estrogenic, but it contains no soy isoflavones, it’s reasonable that lecithin, itself, may be estrogenic - and we may have the exact same result from all vegetable sources of lecithin, or even from animal sources of lecithin.

The food product in the study of most interest to us in the liquid food community were five types of cow’s-milk based infant formula. Of the five formulas, the first three contained lecithin, and the last two did not. They got estrogenic responses as shown in the following chart:

Because F1 and F3, which contain soy lecithin, were so much higher than F5, which had no soy lecithin, they wanted to look into whether lecithin was causing the spike - that’s why they picked up the supplements from the drug store to test, in the first place. But note also how high F4 is, which has no soy lecithin… and note that the LOWEST estrogenicity was from F2, which did, in fact, have soy lecithin. It’s not unlikely, to me, that we’re seeing the effects of variability in the amount of residual hormonal compounds in another ingredient - the cow’s milk.

Lastly, the estrogen equivalency levels they got from these infant formulas, which, like Soylent, probably use the lecithin as an emulsifier, never got as high as 25. for comparison, most of the cheeses they tested scored higher than the infant formulas (as high as 40). One of the authors’ main comments was, “we conclude that dietary estrogens are omnipresent and not limited to soy-based food.” For reference and perspective, three different tofu they tested all scored in the range of 1,000. Not only is soy lecithin in a drink less estrogenic than tofu, it’s apparently less estrogenic than cheese.

As usual, the first study noticing an interesting effect is not conclusive - it’s suggestive, and we really need more work done before we draw any conclusions - much less use them to start making changes in daily practice. Even if lecithin is, in fact, found to have an estrogenic effect, the size that we get from the low quantities used for emulsification don’t look like cause for alarm, just yet.


I’m going to use this everywhere


Really appreciate the care you take checking the research. Thanks.


Another reason to say no to junk food :smiley:


I wonder if the anti-estrogen crowd realizes how much estrogen naturally exists in meat of all kinds, organic included.


Actually, this study looked at four sample of ground meats, blends of pork and beef. In all cases, estrogenicity came in at 0 or 1.

Fish (smoked trout) came in higher, at 10.


I think the best response to the estrogenity concern is just to act more manly if you decide to take soy products, that should provide sufficient counter measure. I found 30 minutes a day of discussing some kind of Man Ball sport, perhaps discussion of many dunks, to provide the necessary testosterone boost. Also wearing a tool belt everywhere you go should help.


Thanks for that thorough breakdown! Much appreciated!

Could anyone clue me in on why some estrogen in the diet is deleterious? I would imagine, and this is not an area I’ve researched, but a bit of estrogen may increase male life spans. To my understanding some phytoestrogens are used in the pill also, so a bit more estrogen for females wouldn’t be too harmful either.

I can see why copious amounts of estrogen or testosterone in the the diet would be hazardous, but I am unaware of where the line is drawn between small amounts and potentially hazardous.

Also, I was under the impression that hops have a fairly high concentration of phytoestrogens, yet I don’t see manly men reeling agains beer. (Last line is a joke of sorts)


Nobody is sure where to draw the line. You’re probably right; in small amounts, it’s a non-issue, because there are both pros and cons. Deciding on which health risks you, personally, face, it may be decidedly pro. For example, if your biggest health risk is coronary artery disease, you’re almost certainly better off getting more.

Possible Pros (for men and women):
Improved plasma lipids (better cholesterol), less hardening of the arteries
Less bone loss
(for women) eases menopause

Possible Cons (for men and women):
Earlier puberty
Increased rate of issues with ovaries or testes
(for women) may make menstrual cycles more erratic

Mythical Cons (largely imagined by BroScience)
Makes men lose testosterone and muscle mass
Causes crying and gynecomastia

The population of real concern is developing embryos, infants, children. I think an adult would have to skew their diet pretty hard toward particular plant sources in order for the phytoestrogens to add up to problematic levels. If there are widespread estrogenic effects happening that we haven’t really noticed yet, they’re more likely to be coming from a common industrial chemical that hasn’t yet been identified as estrogenic (many have, but their use is commonly restricted, especially in food processing.)


Great summary pic:

From this paper:

The pros and cons of phytoestrogens

Heather B. Patisaul and Wendy Jefferson
Front Neuroendocrinol. Oct 2010; 31(4): 400–419.
Published online Mar 27, 2010. doi: 10.1016/j.yfrne.2010.03.003
PMCID: PMC3074428


I was aware of early puberty, but that didn’t seem like a major concern. just gotta keep kids from getting snapchat. In seriousness, the frequency of teenage pregnancies has been going down ( , so even with earlier puberty, we’re managing to control the… consequences. otherwise, what is the downside of that? Perhaps a brain developmental thing, but I have not come across any evidence.

The real issue is the impact on reproductive organs. in which case it would be nice to keep those functioning.

Thanks for the lesson MentalNomad


Lets be crystal clear here, the link/image is to a study on rats, not people…

Studies on you know, people… people need to stop perpetuating bad science… There has been very little evidence to support the Soy is bad for men yet people sing and chant about it like it’s an established fact, it isn’t. There are outliers in any population.

-Edit to clarify, my comment is on the photo/link that says “great summary pic” not the study at the top of the thread, that study does deal with people. The study and graphic from Patisaul and Jefferons study is an animal study and I wanted to be sure that was clear to anyone just glossing through the thread the the findings are not necessarily analogous to human outcomes.


One more I found interesting because of Mental’s “possible negatives” is issues with testes… which is interesting of a statement to make because

Not saying my study beats your study, I’m just trying to give counter point on the reality being nobody can say conclusively either way… Nobody can say soy absolutely can’t cause these issues but nobody can say that it does either. We have conflicting data, limited studies, etc. The only reason it drives me crazy is because most people go around slamming soy which is just silly. At best I think it’s fair to say that while considered generally safe, there may be certain members of any given population which have elevated responses to an abundance of Soy in the diet, but doesn’t that kind of go without saying?


better for prostate and worse for testies could be both, they’re different organs.


Thanks for the anatomy lesson :wink: I was really just attempting to show that for every study that has a negative you just about as easily find a positive. Mainly because in my humble opinion, most of these studies have been quiet limited in population size and makeup. Hence why they appear to point to so many different possible effects good and bad but never really able to confirm or conclusively establish strong links.

i also mainly suspect this is because people view soy in general as safe and harmless making it something doesn’t need further scrutiny (and who would pay for it?). Obviously individuals need to choose and also to listen to their bodies if they make changes. I’m just always dismayed at how often people slam soy and then really can’t give good concrete reasons for doing so when pressed… Soy has a terrible case of fear mongering.


The image is pretty blatantly a rat, based on the rat head and the rat bodies, so I didn’t think that was anything other than crystal clear.

The link is to the article that was the source of the image (credit where credit is due.) It was not a rat study - it was a review article looking at various kinds of research - including studies in multiple animals models (not just rats), including multiple studies with humans (both clinical and observational.)

Actually, outcomes in appropriate animal models are analogous to human outcomes. They’re not identical, but they are analogous. That’s why we do them. True, it’s a mistake to think that anything we find in an animal model will apply directly and identically in people. It’s a bigger mistake, however, to dismiss the results of animal studies we don’t like based on the fact that they’re animal studies; we, after all, are animals, too.

I tried to be clear about the ambiguity between “proven” and “unproven” when I titled my lists as “possible” pros and “possible” cons. The degree of influence on humans is still being figured out.

I think the summary picture is still accurate - it doesn’t refer to any feminizing, whatsoever. That’s just not something really seen in the science.

Also, when I listed the “mythical” fears, I thought I was being crystal clear when when I labelled it as being supported by BroScience; I was trying to make a joke, but I may have been mistaken to presume that we all know what BroScience is. BroScience, defined:

The predominant brand of reasoning in bodybuilding circles where the anecdotal reports of jacked dudes are considered more credible than actual scientific research.

You didn’t know this? Do you even lift? (Kidding. This is another joke, making fun of a meme among BroScientists.)

In the end, this thread was not about dismissing any and all claims of estrogenicity or its effects; it was about clarifying that the particular study in the OP, which is the first I’ve seen bringing up soy lecithin as potentially estrogenic, should not be counted as strong evidence against using soy lecithin in Soylent. The study actually analyzed soy lecithin being used as an emulsifier (in milk-based infant formula), and found it to be a little less estrogenic than cheese. Even if soy lecithin turns out to have some estrogenic properties, the quantities used make it look like a non-issue.


Side note:

I’m thoroughly amused that I started this thread citing Elsevier’s ScienceDirect, but my last post cites the references UrbanDictionary and KnowYourMeme.


My critique stands, you posted the image under the headline that it provided a good summary, I would disagree with you on that point. I also don’t know that it’s crystal clear, yes to anyone reading it and looking through it sure, but as a summary I think it isn’t. If someone reads the text bodies, especially again, since we are talking about humans in this thread, I believe someone could misinterpret that easily enough but then again, thats an opinion. Your post immediately above it you list out your pros/cons and specifically discuss men/woman/embryos, then immediately follow it with a post stating “great summary” and it’s an abstract based on rats, maybe you don’t see the disconnect or how this could easily confuse but I certainly do :confused: I get the humorous aspect, don’t get me wrong, but I feel like there was a leap here in what was in the study vs how you “summarized” it for easy digestion. Also I will admit I haven’t had a chance to read through every word of the study but the only direct testing I could see was animal testing over and over again and the words like “confer”.

Call it an opinion but again, studying the effects of soy on a rat is a great place to start but I would never say it is analogous to human testing. Thats a massive leap… dogs can’t eat chocolate, we understand why now. This is a super simplified example though on why testing chocolate on a dog isn’t analogous to testing on humans. again, gross over simplification but this is a forum on the internet, it’s all relative.


I was jesting, I appreciate your knowledge


Now your just being pedantic.