The Dark Side of Soy

Is America's favorite health food making us sick?

  • Tofu
    Image by Mo Riza, licensed under Creative Commons.

As someone who is conscious of her health, I spent 13 years cultivating a vegetarian diet. I took time to plan and balance meals that included products such as soy milk, soy yogurt, tofu, and Chick'n patties. I pored over labels looking for words I couldn't pronounce--occasionally one or two would pop up. Soy protein isolate? Great! They've isolated the protein from the soybean to make it more concentrated. Hydrolyzed soy protein? I never successfully rationalized that one, but I wasn't too worried. After all, in 1999 the Food and Drug Administration (FDA) approved labeling I found on nearly every soy product I purchased: 'Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease.' Soy ingredients weren't only safe--they were beneficial.

After years of consuming various forms of soy nearly every day, I felt reasonably fit, but somewhere along the line I'd stopped menstruating. I couldn't figure out why my stomach became so upset after I ate edamame or why I was often moody and bloated. It didn't occur to me at the time to question soy, heart protector and miracle food.

When I began studying holistic health and nutrition, I kept running across risks associated with eating soy. Endocrine disruption? Check. Digestive problems? Check. I researched soy's deleterious effects on thyroid, fertility, hormones, sex drive, digestion, and even its potential to contribute to certain cancers. For every study that proved a connection between soy and reduced disease risk another cropped up to challenge the claims. What was going on?

'Studies showing the dark side of soy date back 100 years,' says clinical nutritionist Kaayla Daniel, author of The Whole Soy Story (New Trends, 2005). 'The 1999 FDA-approved health claim pleased big business, despite massive evidence showing risks associated with soy, and against the protest of the FDA's own top scientists. Soy is a $4 billion [U.S.] industry that's taken these health claims to the bank.' Besides promoting heart health, the industry says, soy can alleviate symptoms associated with menopause, reduce the risk of certain cancers, and lower levels of LDL, the 'bad' cholesterol.

Epidemiological studies have shown that Asians, particularly in Japan and China, have a lower incidence of breast and prostate cancer than people in the United States, and many of these studies credit a traditional diet that includes soy. But Asian diets include small amounts--about nine grams a day--of primarily fermented soy products, such as miso, natto, and tempeh, and some tofu. Fermenting soy creates health-promoting probiotics, the good bacteria our bodies need to maintain digestive and overall wellness. By contrast, in the United States, processed soy food snacks or shakes can contain over 20 grams of nonfermented soy protein in one serving.

'There is important information on the cancer-protective values of soy,' says clinical nutritionist Ed Bauman, head of Bauman Clinic in Sebastopol, California, and director of Bauman College. Bauman cautions against painting the bean with a broad brush. 'As with any food, it can have benefits in one system and detriments in another. [An individual who is sensitive to it] may have an adverse response to soy. And not all soy is alike,' he adds, referring to processing methods and quality.

1/15/2021 4:44:42 PM

I agree with a lot of this; but it is 13 years old! I wish you would update it. Has anything changed?

12/29/2020 8:41:13 PM

Some crops are truly domesticated. What I mean is domesticated crops can be harvested, cooked in simple ways and provide sustenance. Tomatoes, potatoes, rice, beans, lettuce, and brassicas come to mind as well-behaved, compliant crops and vegetables. But just like domesticated animals, there are plants that still have rogue traits or misbehave when put under stress. I put soybeans and wheat in the latter category. Such crops have not been completely adapted to us and we have not completely adapted to them. The need for further domestication is apparent when we have to ferment soybeans into miso or shoyu, predigest them with Bacillus subtilis or Rhizopus oligosporus to make nattoh or tempeh, respectively, or make tofu out of soybean milk. Oh, to have shmoos on the menu.

9/23/2020 1:19:42 PM

can anyone tell me if they recognize a story that might have been written by Shirley Jackson about a young sad and lonely woman who is being stalked by a stranger? She eventually resigns herself to her horrible fate and is even looking forward to it?

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