Finally, the Truth About Soy

Post written by Leo Babauta.

Its one of those things that has spread on the Internet and unbelievably, has become accepted truth to many people: that soy is unhealthy, even dangerous.

I mention (to otherwise smart and informed people) that I drink soymilk sometimes, and a look of pity comes over their faces. This guy doesnt know the dangers of soy, and might get cancer, or worse man boobs, theyre thinking.

Just about every fitness expert I read people I respect and trust says that soy is bad for you, from Tim Ferriss to theprimal/paleo folk. Seriously, I respect these guys and otherwise think their work is great. And yet, when I look for their sources on soy, often they dont exist, and when they do, I can always trace them back to one place.

The Weston A. Price Foundation.

Seriously. Ive never seen anyone cite a single peer-reviewed study that shows that soy is unhealthy. The only sources are the Weston A. Price Foundation, or other articles that use the Weston A. Price Foundation as a source (read more).

Heres the thing: the Weston A. Price Foundation (WAPF) have been on a vendetta against soy (and for meat and raw milk) for a couple decades now, and they have no solid evidence to back up their vendetta. They have lots of quasi-scientific evidence, lots of reasonable-sounding arguments, but if you look for solid proof, you wont find any. They are not scientists, and have conducted no actual peer-reviewed studies of their own (that I know about).

Im not going to tell you to fill your diet with soy. I eat it moderately, like anything else, but am not afraid of it. What I am going to do is clear up some myths, and challenge those who disagree with me to show actual peer-reviewed studies (not ! articles by WAPF or that cite WAPF as their source).

Who are the Weston A. Price Foundation?

I wont do an entire treatise on WAPF, as others have done it better:

Id encourage you to read these and consider the arguments and evidence, not the sources. While some of these articles are from vegetarians, that doesnt negate the arguments they just seem more motivated to do the research on WAPF than most people are.

But basically the WAPF is a fringe group that advocates some weird health claims about meat, raw milk, butter but who came along just at the time when the meat and dairy industry was worried about soy being promoted as a healthy alternative. WAPF claims they dont take money from agribusiness or the food processing industry, which is both true and admirable but they do receive funding from sponsors and members a large percentage of whom are dairy and meat farmers.

Anyway, the problem is not where their funding comes from its their science. Sally Fallon (WAPF founder), board member Dr. Joe Mercola, and other WAPF authors use quack science to promote their agenda, and yet most people cant distinguish between good and bad science. When they make claims about Eskimo diets being entirely meat and fat based, that sounds reasonable to ! most peo ple, who dont realize that you cant just observe a people and make conclusions that are then generalized to other populations, or that the Inuit Greenlanders had the shortest life expectancy of any indigenous North Americans and high cancer rates (read more). Most people dont understand how empirical science is done, and so dont understand why criticism by the WAPFs Chris Masterjohn of The China Study is a misinterpretation of the evidence.

Dont take my word for it. Read the links above, become informed, weigh the evidence. Ask for the results of actual peer-reviewed studies, instead of relying on scientific-sounding arguments.

Does soy contain dangerous estrogens?

One of the most-repeated of WAPFs myths about soy is that it contains dangerous estrogens that will cause cancer, man boobs, and a host of other health problems. So I thought it would be good to clear this up.

There is no evidence that eating soy causes any of the problems caused by raised levels of estrogen (a hormone thats already naturally in our bodies).

The confusion that WAPF plays on is that soy contains a natural, non-steroidal compound called phytoestrogens but actually many other plants contain phytoestrogens too, including flaxseeds, sesame seeds, hummus, garlic, peanuts, and more.

Phytoestrogens are not estrogens, and though they might be similar, they have completely different effects on the human body. They do not affect the sperm count or concentration in men, nor do they affect the size of your testicles or volume of ejaculate (more). They dont cause breast cancer in women (more).

Soy infant formula, while not nearly as good as human breast milk, is safe (more and more).

As you can see, Ive linked to a few peer-reviewed studies that look at actual evidence, not pseudo-scientific arguments. There are many more that are easily found via Google. If you read or hear people making claims about soy and estrogen, ask for the sources, and ask that they be peer-reviewed studies.

Has soy been shown to be unhealthy?

In a word: no.

While I wont claim that soy is a magic bullet for getting healthy, it also doesnt have the dangers that WAPF and others claim it does. In fact, there is no evidence for any of those claims. I wont get into all the claims, but just touch on a couple of the prevalent:

1. FALSE: Soy inhibits the digestion of nutrients (anti-nutrients). Its true that soy, like many plants, have anti-nutrients but when you cook, ferment, soak, roast, or sprout these plants, you do away with the anti-nutrients. From Dr. Andrew Weil: There is no scientific data suggesting that soy consumption leads to mineral deficiency in humans. (more) Fallon, Enig, and the other WAPF have failed to provide any evidence at all for this claim (more).

2. FALSE: Soy increases the risk of cancer. In fact, the evidence shows just the opposite. The Health Professionals Follow-up Study found a 70% reduction in prostate cancer for men who consume soy milk daily. The American Institute for Cancer Research, in collaboration with the World Cancer Research Fund, issued a major report in 1997 that analyzed more than 4,500 research ! studies, with more than 120 contributors and peer reviewers, including those from the World Health Organization, the Food and Agriculture Organization of the United Nations, the International Agency on Research in Cancer, and the U.S. National Cancer Institute. The report said that Phytoestrogens are found in high concentrations in soya beans, and have been shown in vitro to exhibit a plethora of different anti-cancer effects, including inhibiting proliferation. The report found some evidence that soy protects against stomach and prostate cancers. In 2000, Riva Bitrum, the President of Research for the American Institute for Cancer Research, said that Studies showing consistently that just one serving a day of soyfoods contributes to a reduction in cancer risk are encouraging. Consuming one serving of soyfoods is a step most individuals would not find too difficult to take. For healthy women, according to the American Institute for Cancer Research, even two or three servings a day of soyfoods should be fine as one part of a mostly plant-based diet. (more)

3. FALSE: Soy causes (insert scare claim here: Alzheimers, birth defects, etc.). There isnt any evidence for any of the scare claims that originate from WAPF. Im not going to argue them all, but I urge you to read these articles from John Robbins, Dr. Neil Barnard, Syd Baumel, and Dr. Joel Fuhrman they contain many more sources than I could list here, and theyre based on actual evidence.

4. Legitimate concerns. Like most foods (meat, milk, peanuts, nuts, berries, chocolate, etc.), there are people with certain conditions that should be more ca! reful. N one of the legitimate concerns about soy are causes for alarm. Some people are allergic to soy. There is conflicting evidence about soys effect on women who already have breast cancer some evidence suggests that it might be beneficial, but its not conclusive. If you already have a thyroid disorder, excess soy consumption (more than a couple times a day) could affect thyroid function (more). Genetically modified soybeans (common in the U.S. because of Monsanto) are not as healthy as organic soybeans try to eat organic more than not. Soy formula for infants is less healthy than human breastmilk (as is milk-based formula) though decades of people brought up on soy formula as babies have shown no ill effects. Still, human breastmilk is much better. Again, none of these legitimate concerns is anything to be scared about most people can eat soy a few times a day with no effects, according to the overwhelming mass of evidence, and even those who might have a concern can eat some amounts of soy with no problems.

So should I eat soy?

I honestly dont care if you do or not. My general recommendation is to eat mostly real, whole foods veggies, fruits, nuts, beans, seeds, a moderate amount of whole grains. I dont eat meat or dairy for ethical reasons, but if you do eat meat, you should limit your intake of red meat (many studies have shown the health risks of red meat).

But soy has been eaten in moderation for centuries, and as I said above, has not been shown to be unhealthy. It can be included in a healthy diet tofu, some soy milk, who! le soy b eans, tempeh can all be good for you if you mix them in with the other real foods I mentioned above. Soymilk is basically whole soy beans soaked in water and squeezed to produce a milky liquid, and tempeh is actual soybeans fermented.

I would be cautious about overly processed soy foods processed soy protein just as I would any other processed foods. Meaning, dont be afraid of them, but dont make them a major part of your diet. Eat real foods instead.

As a last note to doubters: I welcome your doubt its important not to take my word as final. But instead of rebutting me with scientific-sounding arguments, show me the peer-reviewed studies. And not just one study, as no one study will be proof of anything show me the mass of research thats been done. When you look at the entirety of the research that has been done on soy, the evidence is overwhelmingly clear. Id love to see someone show otherwise.

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