From the joys of soy to the soy of cooking, by now you've probably heard every cute soy cliché there is. Thanks to study after study linking the Asian wonder bean to the relief of menopausal symptoms, lower cholesterol levels, the prevention of cancer and bone disease - you name it, the hippie food once relegated to health food stores has secured a prominent place on supermarkets shelves and North American dinner tables. However, more recently, a number of media reports have taken a bite out of the hype. New research indicates that skyrocketing "not dog," Gardenburger and soyaccino consumption may actually be doing squat to combat all of the above. But more than that, a shocking study recently suggested that the type of soy most favoured by North Americans, the highly processed soy protein in everything from soy milk to soy power bars, even some tofu, may actually stimulate growth of breast tumours. And that's not the only condition the so-called miracle food may be aggravating.
So the question is, should you ditch soy? The answer is complicated. ***
The "yellow jewel's" centuries-old history in Asian cuisine is by now common knowledge. Low rates of hot flashes, prostate and breast cancer among Asian populations have been seen as an indication of just how healthy soy must be. But even that supposition is being reconsidered. Yes, Asians do eat soy, but not nearly as much as, say, a typical North American vegetarian or vegan. Not to mention those ingesting the soy oils lurking in 60 per cent of all processed foods, hidden under vague labels like "vegetable oil" or "hydrolyzed vegetable protein." "Soy is full of natural toxins (such as protease inhibitors) and estrogen-like compounds, and if it's not eaten the way it is in an Asian diet, which is in small amounts as a fermented food (like tempeh and miso), but instead in the way (the soy industry) wants us to eat it here, it's very risky," says Sally Fallon, president of the Washington-based Weston A. Price Foundation. (Tofu sold in grocery stores, by the way, is not usually fermented. Fermented tofu is often sold in jars in Chinatown.)
As North Americans started using soy oil as a cheap and purportedly healthier replacement for saturated-fat-laden butter and animal shortening, the amassing quantities of leftover soy protein were processed and fed to animals, and soon to humans.
Refining processes have improved over the years, admits Kaayla T. Daniel, author of the soon-to-be-released The Whole Soy Story. "But there are still a whole lot of toxic by-products that come through, and they're still using petroleum solvents." Above all, whether fermented or processed, soy products still contain hormone-mimicking phytoestrogens.
You're not mistaken if you think phytoestogens have been billed as a good thing, especially when it comes to menopause. The hormone-balancing effect of soy to help ease hot flashes and night sweats was trumpeted throughout the 90s. But since then, many scientists have admitted that much of the research has failed to uphold those claims.
Patents have sat unused as companies dropped efforts to market pills filled with soy isoflavone (a type of phytoestrogen). The North American Menopause Society carefully retracted its support of soy's therapeutic treatment for hot flashes earlier this year, stating that the clinical evidence neither supports nor refutes it. And menopause gurus like neuro-gynocologist Larrian Gillespie, author of The Menopause Diet, started warning women of the dangers and side effects of self-medicating with soy.
"If you've got thyroid problems, you don't want to use soy, because the isoflavones interfere with thyroid function and increase hypothyroidism." Gillespie tells NOW that she went into full-blown hypothyroidism, goitre and all, within 72 hours of taking just 40 mg of isoflavones in a capsule.
The British Committee on Toxicology, which did the most comprehensive literature review to date on phytoestrogens, agreed in its report issued last year, "Consumption of phytoestrogen supplements or a soy-rich diet may provide sufficient concentrations of phytoestrogens to interfere with thyroxine replacement therapy."
But perhaps more disturbing to all the women religiously consuming soy in the belief that soy might help prevent breast cancer (as some studies have indicated), the report also acknowledged evidence that phytoestrogens may actually stimulate progression in breast cancers. Dozens of rodent studies have demonstrated just that, including the groundbreaking one released in May that said super-processed soy products and supplements containing purified isoflavones are associated with tumour growth in post-menopausal women.
"If you're consuming soy food as part of a healthy diet as it's consumed in Asia, then you're probably fine at any time. But if you have an estrogen-responsive cancer and you're consuming a diet high in isoflavones from soy protein isolates or supplements, that's a whole different area," says William Helferich, professor of food science and human nutrition at the University of Illinois at Urbana-Champaign. "The animal data tends to support that these compounds can make an estrogen-responsive tumour grow." He adds that in one of his previous studies, isoflavones actually negated the effect of mainstream breast cancer drugs.
Helferich is concerned that on top of soy supplements and protein found in foods like soy milk, a new source of isoflavones has recently been creeping into our diets - through low-carb foods. "A lot of the time, they're replacing the carbohydrates in breads or whatever with soy protein isolates."
Of course, it all becomes more complicated when you consider that isoflavones vary wildly from one product to another. (Soy ice cream and burgers contain very little and soy milks and powders generally contain more.) Plus, strangely, the same hormones in less processed foods like soy flour did not trigger any tumour growth.
Still, Helferich is among the many observers who are unsettled by the fact that the soy industry in the U.S. is now petitioning the Food and Drug Administration for the right to put cancer-fighting claims on soy products. The industry already secured a heart disease health claim a few years ago (as the Canadian soy industry is currently lobbying to do here). That claim pushed two of the FDA's own toxicologists to break ranks and speak out against the dangers of soy, calling it "a large, uncontrolled and basically unmonitored human experiment."
When it comes to explaining soy's rise to the top of the food chain, the Price Foundation and others point to massive public relations and lobbying efforts on the part of the big guns at the top of the soy biz. Farming oligopoly giant Archer Daniels Midland patented the term Textured Vegetable Protein (sorry, TVP lovers). Chemical behemoth Dupont is part owner of Solae, the company that makes much of the soy protein in your fave foods made by Yves, So Good and Gardenburger. Solae's protein is used in 60 per cent of experiments done on soy. Solae also happens to be the company pressing for the FDA claims. And, according to critics, the industry funds much of the soy research out there.
The Price Foundation even links research attacking red meat and saturated fats over the last couple of decades to the soy lobby. However, it's important to note that the foundation is outspoken against veganism, is in part funded by farmers and supports a return to beef and animal fats, albeit grass-fed. And if you look at the foundation's board of directors, nearly every well-known soy detractor, including author Daniel, is on the list.
The foundation is now searching for plaintiffs for a class-action lawsuit against the soy industry. "We get one or two really sad stories a day," says Fallon. "The saddest ones are about babies on soy formula (whose parents) realize their babies will never have a normal sex life. The little boys are very feminized, (have) very small sexual organs and real strange behaviour problems. And we're hearing quite often (about) two-year-old (girls) with breast buds and body odour. It's shocking."
But Anthony Otley, a pediatric gastroenterologist on the nutrition committee of the Canadian Paediatric Society, says such statements implicating soy formula scare parents unnecessarily. "A lot of very reactionary groups have said that (infants on soy formula get too much estrogen) and don't look further into it."
Otley admits that when animals are given large doses of phytoestrogens, they experience changes in sexual maturation and organ development. But he cautions that it's important to remember that babies aren't being injected with the hormone as lab animals are. Rather, they ingest it, and by processing it in their gut, a "significant majority of the hormone is inactivated." Besides, adds Otley, breast buds in infants as young as one or two years are relatively common and may not be a result of soy consumption.
Still, he admits there was no reason for 20 per cent of Canadian babies in the mid-90s to be fed soy formula. That's when the Paediatric Society and Health Canada decided to recommend that soy formula only be fed to infants by doctor's orders (i.e., if the baby is allergic to cow's milk formula) or if the parents are vegan. Cow's milk, they say, is just closer to human milk.
"Certainly, if we did discover that there's a risk to consumers, we'd take immediate action," says Health Canada's Margot Geduld. "But at this moment, based on the evidence we have, we feel soy is a good source of protein as part of a healthy and balanced diet."
But some say a balanced diet is exactly what many vegetarians don't have, consuming large amounts of soy at nearly every meal. Even Soyfoods Canada isn't sure how safe that is. "Overconsumption of soy, does it have any negative effects? I don't know if anybody has any conclusive evidence on that," says the group's VP, Carla Bertoia. "We at Soyfoods Canada just want people to incorporate it into their diets. We don't want people to actually live (only) on soy."
Yet soy researchers like U of T's David Jenkins stand by the health food. "I'd like to flip the question and ask, 'What protein source do you want to put in its place?'" asks Jenkins. If there are to be warnings for soy, he says there should be warnings for beef, chicken and mercury-laden fish. "Singling out one food is not reasonable in the face of all our other problems."
Bottom line, say researchers on all sides, is that more work is needed before conclusions can be drawn.