As someone 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 soymilk, soy yogurt, tofu, and Chick’n patties. I pored over labels looking for words I couldn’t pronounce. Occasionally an ingredient or two would pop up among my fake sausages. Soy protein isolate? Great! They’ve isolated the protein from the soybean to make it more concentrated in my veggie dogs. Hydrolyzed soy protein? I never successfully rationalized that one, but I wasn’t too worried. After all, in 1999, the FDA approved labeling 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 are not only safe—they’re beneficial.
After several years of consuming various forms of soy nearly every day, something wasn’t right. 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 eating edamame or why I was often moody and bloated. It didn’t occur to me at the time to blame 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 there was a connection between soy and reduced disease risk, others cropped up to challenge these claims. What was going on?
“Studies showing the dark side of soy date back 100 years,” says Kaayla Daniel, PhD, clinical nutritionist and author of The Whole Soy Story: The Dark Side of America’s Favorite Health Food.Ê “The 1999 FDA-approved health claim pleased big business, despite massive evidence showing risks associated with soy, and against the protests of the FDA’s own top scientists. Soy is a global four-billion-dollar industry that’s taken these health claims to the bank.” Besides heart health, the industry says that soy consumption 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 much lower incidence of breast and prostate cancer than in the US, and many of these studies trace the results back to a traditional diet that includes soy. Daniel says a common misconception is that Asians are consuming more soy than they actually are; soy accounts for only about 15 percent of their total calories, or nine grams per day. Asian diets include small amounts of primarily fermented soy products, such as miso, natto, and tempeh, and some tofu. By contrast, in the US, processed soy food snacks or shakes can contain over 20 grams of soy protein in one serving.
“There is important information on the cancer protective values of soy,” says Ed Bauman, PhD, clinical nutritionist, head of the Bauman Clinic in Sebastopol and director of Bauman College of Holistic Nutrition, who cautions against painting the bean with a broad brush. “As with any food, it can have benefits in one system and detriments in another. If there is an individual sensitivity, one may have an adverse response to soy. And not all soy is alike,” he adds, referring to processing methods and quality.
Soy is indigenous to Eastern Asia, where it was once considered toxic and used only as a cover crop. It was eventually fermented for better digestibility; it had long been known that soy caused extreme digestive distress if consumed raw or undercooked. Fermenting soy deactivates these harmful constituents and creates health-promoting probiotics, the good bacteria our bodies need to maintain digestive and overall wellness. Daniels mentions that Asian populations may have had success with soy because they are consuming primarily the fermented forms.
As soy moved west, it became a new addition to the diets of Europeans and Americans. “Soy is not a native food to North America or Europe, and I think you have issues when you move food from one part of the world to another,” Bauman says. “We fare better when we eat according to our ethnicity. I think soy is a viable food, but we need to look at how it’s used and maybe consider using other food stock that’s more indigenous.”
Formerly considered a small-scale poverty food, soy exploded onto the American market. Studies—funded mostly by the industry—began singing the praises of soy’s ability to lower disease risk while absolving one from guilt associated with meat consumption. “The soy industry has come a long way from where some hippies would start boiling up the beans,” says Daniel. “It’s very much about the marketing.”
Marketing includes spotlighting philanthropic efforts. The soy industry would like us to believe that it can alleviate the world’s hunger problem by introducing soy to third world countries. “Rather than encourage people to grow a variety of indigenous things, the industry goes in and basically replaces wheat, lentils, vegetables and chickens and goats with soybean plants,” Daniel says. Most often those plants are genetically modified to withstand spraying with herbicides such as Roundup and Partner. The aim is to reduce competition by weeds and grasses, a boon for agribusiness.
Large farm or small, the environmental effects of introducing a non-indigenous crop can be detrimental. “In Argentina and Brazil, most of the big farms are eating up the rainforest for GM soy, and they’re using massive amounts of pesticide,” Daniel says. “People in the surrounding areas are developing all sorts of health problems. They’re busy exporting the soy to places like China rather than focusing on growing their own food.”
By now, the industry has discovered ways to use every part of the bean for profit. Soy oil has become the base for most vegetable oils; soy lecithin, the waste product left over after the soybean is processed, is used as an emulsifier; soy flour appears in baked and packaged goods; different forms of processed soy protein are added to everything from animal feed to muscle-building protein powders. “Soy protein isolate was invented for use in cardboard,” says Daniel. “It was approved for packaging but it was never given GRAS [generally regarded as safe] status. It hasn’t actually been approved as a food ingredient.”
Soy is everywhere in our food supply, as the star in cereals and health-promoting foods or hidden discreetly in processed foods. Even if you read every label and avoid cardboard boxes, you’ll likely find soy in your supplements and vitamins (look out for vitamin E derived from soy oil), in foods such as canned tuna, soups, sauces, breads, meat (injected under poultry skin), and chocolate, and in pet food and body care products. It may hide in your tofu dogs under such aliases as textured vegetable protein (TVP), hydrolyzed vegetable protein, or just plain lecithin.
Extensive processing to hydrolyze soy protein into vegetable protein produces excitotoxins such as glutamate (think MSG) and aspartate (a component of aspartame) as byproducts. Food-borne excitotoxins are ubiquitous in processed foods and cause brain cell death.
Soy is one of the most allergenic foods, in addition to wheat, corn, eggs, milk, nuts, and shellfish. Most people equate food allergies with anaphylaxis, or a severe emergency immune response, but it is possible to have a subclinical sensitivity to a food. These lead to health problems over time and are exacerbated by a lack of variety so common in today’s American diet.
“People can do an empirical food sensitivity test by eliminating the food for a period of time and reintroducing it to see if there’s an immune response, but most don’t do this,” says Bauman. “Genetically modified soy is the most problematic, and that’s probably what most people are eating if they’re not paying attention. People can develop a sensitivity to a food that has antigens or bacteria not originally in the food chain, as is the case with GM foods.”
Agri-giant Monsanto obtained FDA approval to market GM soy in 1996, and by 2004, a staggering 85 percent of the US crop was genetically modified. Daniel says, “One question I get all the time is, ‘What if I only eat organic soy?’ Their assumption is that GM soy is problematic and organic is fine. Certainly, organic is better, but the bottom line is that soybeans naturally contain plant estrogens, toxins and anti-nutrients, and you can’t remove those.”
Anti-nutrients block enzymes needed for digestion. Soy’s naturally occurring phytates block absorption of essential minerals such as zinc. This is most worrisome for vegans and vegetarians consuming soy as their main source of protein, and for women in menopause who may be further upping their soy intake through supplements.
The highest risk population is infants. “The reason,” says Daniel, “is because it’s the only thing they’re eating, they’re a very small size, and they’re at a key stage developmentally. The estrogens in soy will affect the hormonal development of these children, and it will certainly affect their growing brains, reproductive systems, and thyroids.” Soy formula also contains large amounts of manganese, which has been linked to ADD and neurotoxicity in infants. Such effects prompted an investigation by the Israeli Health Ministry that resulted in an advisory stating that infants should avoid soy formula altogether.
Soy contains phytochemicals—plant nutrients with disease-fighting activity—called isoflavones, which act as plant estrogens (phytoestrogens) in humans. Studies claim that isoflavones can mimic the body’s own estrogens, raising a woman’s estrogen levels, which fall after menopause, causing hot flashes and other symptoms. On the other hand, the phytoestrogenic effects of isoflavones may also block the body’s estrogens, which can help reduce a woman’s high estrogen levels, therefore reducing her risk for breast or uterine cancer before menopause. High estrogen levels have been linked to cancers of the reproductive system in women.
Isoflavones are thought to be useful in warding off cancer due to their antioxidant effect, neutralizing cancer-causing free radicals in the body. Although soy’s isoflavones may have an adaptogenic effect—contributing to an estrogen-boosting or -blocking effect where needed—they may also have the potential to promote hormone-sensitive cancers in some people. Studies on isoflavones’ effects on human estrogen levels are conflicting and it is possible that they affect people differently. In men, soy has been shown to lower testosterone levels and sex drive, according to Daniel.
Bauman believes processed soy foods are problematic but maintains that soy has beneficial hormone-mediating effects. “People are largely convenience-driven. We’re looking at this whole processed food convenience market and we’re making generalizations about a plant. Is soy the problem, or is it the handling and packaging and processing of the plant that’s the problem?”
“Primary sources of food are a good thing,” Bauman states. “Once there was a bean, but then it got cooked and squeezed and the pulp was separated out, and it’s heated and processed for better shelf-life and mouth feel. Soymilk is second or third level in terms of processing.”
Bauman’s eating-for-health approach entails ingesting a variety of natural and seasonal unprocessed whole foods, including soy in moderation, tailored to one’s biochemical individuality and sensitivities. “Using soy as a part of a diet can bring relief for perimenopause, for example,” he says. “Throw out the soy and you throw out the isoflavones.” (It is possible to obtain phtyoestrogens to a lesser extent from other foods, such as lima beans or flax.) “The literature is extensive on the benefit of soy, and that should always be stated, just as the hazards should be. That’s science. These studies are not ridiculous or contrived, but take a look at them. Who’s funding them?” asks Bauman.
“There are a lot of problems with these studies,” Daniel says, adding that the 1999 heart health claim was an industry-funded initiative. “My position is that even if there is positive information, and even if these studies are well designed, we need to weigh that against the fact that we’ve also got really good studies showing the dangers. The precautionary principle states better safe than sorry. Possible benefits are far outweighed by proven risks.”
Dietary needs are different for everyone and change according to the body’s needs. Daniel and Bauman both agree on the benefits of variety. “As a clinical nutritionist, my experience is that people who have a varied diet tend to not get into trouble,” says Daniel.
“We like to demonize certain foods in this society,” says Bauman. “If you want to find fault, you’ll find it. The bottom line is, what is a healthy diet?”