My best friend, Alex, was sixteen when she decided to stop eating meat. Her love of animals and her distaste for the sinewy feeling of meat between her teeth left her seeking vegetarian alternatives to her old steak and chicken staples. When she discovered soy products, she quickly became a fan; not only could she continue to make her beloved “beef” tacos, but soy substitutes were also a good protein supplement. “The taste wasn’t too different,” Alex says. “It helped me feel like I was still eating substantial meals.”
But how healthy is soy, really? The plant has been a dietary staple in East Asian cultures for thousands of years, and Americans have jumped on the bandwagon recently—between 1992 and 2008, soy-product sales increased from $300 million to $4 billion in the U.S. Whereas soy used to be relegated to health-food stores, now we can find it in just about every supermarket. Are we on our way to longer, healthier lives?
Not exactly. “The bulk of soy products that you can buy in the States are processed and altered so much that the original East Asian consumers wouldn’t even recognize them,” says Alex, who recently earned a degree in nutrition science.
Some studies have linked soy to infertility, breast cancer, thyroid problems, and other health issues. How true are these claims? Is soy a truly healthy alternative to dairy? What are our other options? I dove into the research surrounding some of these questions to see what scientists have really discovered—sans spin and sensational headlines.
All Soy Isn’t Created Equal
Luckily, conflicting claims about soy are mostly reconcilable—we just have to get a little more specific. Jenny Geyser, a San Diego–based personal trainer, cautions people on eating overly processed soy in particular, which she claims has “lately been shown, through many studies, to be harmful.” Avoiding this potential harm means steering clear all processed soy products, including the “soy protein isolate” found in powders, bars, and those soy hot dogs, ice creams, protein shakes, and meats you see.
We’ve taken soy to a whole new level—just think about all the new soy products you see in grocery aisles (we’re not talking just miso soup and tofu anymore). All those studies touting the benefit of soy are correct—the fermented soy present in traditional Asian diets does have great health benefits. But tofurkey? Not so much.
What Is Unprocessed Soy?
In The Whole Soy Story, Dr. Kaayla Daniel discusses the differences in Eastern and Western cultures’ soy consumption. Traditional Asian eaters consume highly digestible, fermented soy, like miso, tamari, tofu, tempeh, and soy sauce—not fancy versions of America’s favorite junk foods. The main disparity, Daniel writes, is that people in Asia eat small amounts of whole-soybean products, while Western processors separate the beans into the protein and the oil. Traditional Asian products also use whole beans that are fermented for at least three months; this important part of the process makes the bean more digestible. High-tech processing does just the opposite—it increases the beans’ toxic and cancer-causing residues with high temperatures, pressures, and chemicals. Without fermentation, soy provides far fewer health rewards—it actually inhibits calcium, iron, and zinc absorption.
This means that all of our newfangled, “healthy” soy products actually fall into the processed-food category. And, as we’ve now been told millions of times, processed food is one of those things that we should make the exception, not the rule, in our diet.
Does Soy Lead to Infertility?
Some studies have shown that eating high levels of soy protein does have harmful effects on our ability to reproduce—but only when we’re taking in much, much more soy than average over a long period of time. So breathe easy, Silk Milk lovers—a glass of soymilk a day and the occasional tofu salad probably aren’t going to leave you childless, according a study published by Wake Forest Baptist University Medical Center. Researchers found that subjects who took soy supplements containing twice the amount of that eaten by most women in Asia over one year didn’t cause any negative changes in menstrual cycles or ovarian function.
