Many people ask me “Why am I so Against eating Soy Products – Aren’t they natural and fat free?”

Fat free they may be but natural? I don’t think so!

But don’t take my word for it… Kaayla T. Daniel, PhD, CCN has the whole story.

Kaayla T Daniel

Over the past decade, soy has been widely promoted as the “healthy” solution for dieters on low-carb diets. Soy protein, after all, is low in carbs and fat, high in protein and touted as a “miracle food” that can prevent heart disease, fight cancer, fan away hot flashes and build strong bodies in far more than 12 ways. Sales of soy foods reached a whopping $4 billion in 2004, with most segments of the industry reporting double-digit growth.

The marketing of soy as a low-carb health food has been so successful that few people realize that respected scientists have warned that possible benefits should be weighed against proven risks. Even researchers working for the soy industry have admitted at soy symposia that the “marketing is way ahead of the science.”

Fortunately, the “whole soy story” is starting to emerge.

Late July, the Israeli Health Ministry warned that babies should not receive soy formula, that children under 18 years of age should eat soy foods no more than once per day to a maximum of three times per week and that adults should exercise caution because of adverse effects on fertility and increased breast cancer risk. The Ministry took its advice from a 13-member committee of nutritionists, oncologists, pediatricians and other experts who spent a year examining the evidence. The committee was most concerned by the possibility of hormonal disruption caused by the estrogen-like plant hormones in soy.

In July, researchers at Cornell University’s Program of Breast Cancer and Environmental Risk Factors also warned that excessive soy food consumption can increase breast cell multiplication, putting women at greater risk for breast cancer. Then just in time for Breast Cancer Awareness Month in October, the Journal of the American Dietetic Association reported that the studies on soy and cancer are inconsistent and that high intake of soy may increase breast cancer risk. The Journal indicated this lack of “clear, consistent message” confuses many women and that “health professionals should take an active role in communicating and clarifying such information.”

The main reason that most midlife women eat soy, of course, is their hope that the soy phytoestrogens known as isoflavones will alleviate hot flashes and other menopausal symptoms. That myth has recently been dashed as well. In September the U.S. Agency for Healthcare Research and Quality released a report in which it concluded that soy products may reduce menopausal symptoms but noted that nearly all of the studies were of poor quality or their duration was too short to lead to definite conclusions. The team found that soy products may benefit LDL cholesterol and triglycerides levels, but that the amount of soy protein needed for lipid reduction is unknown and the effects appear to be of small clinical benefit for individuals.

These and other warnings follow a lengthy report issued in 2002 by the British Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment, which found no merit to most of the health claims made for soy phytoestrogens. The Committee was particularly concerned about evidence that that they cause thyroid damage, and identified infants on soy formula, vegetarians who use soy as a primary source of protein and adults trying to prevent disease with soy foods and soy supplements as being at risk for thyroid damage.

For consumers such news can be confusing. After all, “everyone knows” that Asians eat large quantities of soy and consequently remain free of most western diseases. In fact, the people of China, Japan and other countries in Asia eat small quantities of soy and as condiments, not as staple foods. While it is true that Asians show lower rates of breast, prostate and colon cancers, they suffer higher rates of thyroid, pancreatic, liver, stomach and esophageal cancers. Thyroid disease is also prevalent in Asia, with an epidemic of cretinism in some parts of China and with “Hashimoto’s thyroiditis”and other thyroid problems common in Japan.

Asians also eat different soy foods from the ones now favored by low-carb dieters. Think small amounts of traditional whole soy foods such as miso, natto, tempeh, tofu, tamari and shoyu, not veggie burgers, “energy bars,” shakes, TVP chili, soymilk or other meat or dairy substitutes. Contrary to popular belief, soy milk was rarely drunk in Asia prior to the 20th century and soy formula was first invented by a Baltimore pediatrician in 1909.

Today’s familiar soy protein ingredients such as soy protein isolate, soy protein concentrate, textured soy protein and hydrolyzed plant protein were unheard of until after World War II. These quintessentially western products are manufactured using high-tech, industrialized processes that destroy protein quality, reduce vitamin levels and leave toxic residues, including excitotoxins and carcinogens. Although the latest refining techniques yield blander, purer soy proteins than the “beany,” hard-to-cover-up flavors of the past, the main reason that the new soy foods taste and look better is the lavish use of unhealthy additives such as sugar and other sweeteners, salt, artificial flavorings, colors and the monosodium glutamate.

Soy is now an ingredient in more than 60 percent of the foods sold in supermarkets and natural food stores. Much of it is “hidden” in products where it wouldn’t ordinarily be expected, such as in fast-food burgers, breads and canned tuna. Although the quantities are usually small, this is becoming a nightmare for the growing numbers of people who are allergic to or sensitive to soy. Soy is now widely ranked as one of the top eight allergens and some experts put it in the top four.

Making matters even worse, much of today’s soybean crop is genetically modified. GM beans carry higher levels of antinutrients, toxins and allergens than regular soybeans and have caused vast damage to the environment. Indeed, more of the Amazon Rainforest has been lost to GM soybean farming than to beef grown for fast-food franchises.

Unfortunately, the health problems caused by soy are not completely solved by eating whole bean products and buying organic. All soybeans naturally contain antinutrients, toxins and plant hormones. The best known of these are protease inhibitors (which interfere with protein digestion and have caused malnutrition, poor growth, digestive distress and pancreatitis), phytates (which block mineral absorption, causing zinc, iron and calcium deficiencies), lectins and saponins (linked to “leaky gut” and other gastrointestinal and immune problems), oxalates (which can promote kidney stones and vulvodynia) and oligosaccharides (which cause gas, giving soy its reputation as the “King of Musical Fruits”).

Apologists for soy dismiss such claims, saying that food processing and home cooking remove most of these antinutrients. In fact, modern processing removes most of them but not all. The levels of heat and pressure needed to remove all protease inhibitors, for example, severely damage soy protein and make it harder to digest. The trick is to eliminate the most

antinutrients while doing the least damage to the soy protein. Success varies widely from batch to batch.

For years the the U.S. Department of Agriculture and the soy industry tried to improve the quality of animal feeds and spent massive amounts of money carrying out research to find ways to get rid of these undesirable antinutrients. Although they succeeded to a certain extent, producers must still supplement animals feeds heavily with vitamins, minerals and methionine, a sulfur-containing amino acid that is low in soy. Even so, makers of animal chows are still limited in the amount of soy they can add without causing growth and fertility problems. Food processors making soy-protein products for people may or may not add these supplements. Generally, calcium and vitamin D are added to soy milk so it can compete with dairy products.

Today, the soy industry has switched tactics – from trying to remove the unwanted antinutrients to trying to convince people that they are actually a good thing. Protease inhibitors, saponins and lectins are being touted as curers of cancer or lowers of cholesterol, while phytates are being recommended for their ability to remove toxic minerals such as calcium and excess iron from the body. Although some of these uses look promising, it is important to note that researchers are not achieving these successes using regular soy foods. Most take carefully extracted components and administer them in carefully measured and monitored doses. Soy industry press releases to the contrary, there’s no reason to think that just eating a lot of soy foods will do the trick.

Most dangerous of all, all soybeans naturally contain high levels of phytoestrogens. Although these are said to be “weak estrogens” and are promoted as “safe and natural,” they are “strong in numbers “and can cause significant endocrine disruption, leading most often to hypothyroidism with its symptoms of weight gain, fatigue, brain fog and depression.

More than 70 years of human, animal and laboratory studies show that soybeans put the thyroid at risk. Although individuals who are deficient in iodine are especially prone to soy-induced thyroid damage, damage can also occur even when iodine levels are replete. Adults who boost their thyroid with drugs such as Synthroid while also eating thyroid-inhibiting foods such as soy put extreme stress on their thyroids and increase their risk of developing thyroid cancer. Accordingly, many physicians now recommend that thyroid patients either avoid soy altogether or take their medications separate from their soy.

Phytoestrogens also have a “contraceptive effect.” Fertility problems in cows, sheep, rabbits, cheetahs, guinea pigs, birds and mice have been regularly reported since the 1940s. In women, soy can alter menstrual cycles, causing hormonal changes indicative of infertility. In men it can lower testosterone levels, the quantity and quality of sperm and the libido. Although scientists discovered only recently that soy lowers testosterone levels, tofu has traditionally been used in Buddhist monasteries to help the monks maintain their vows of celibacy. Couples who desire to become pregnant are wise to cut out soy.

Humans and animals appear to be the most vulnerable to the effects of soy estrogens prenatally, during infancy and puberty, during pregnancy and lactation, and during the hormonal shifts of of menopause. Of all these groups, infants on soy formula are at the highest risk because of their small size and developmental phase, and because formula is their main source of nutrient. Soy formula now represents 25% of the bottle fed market in America and has been linked to premature puberty in girls, delayed or arrested puberty in boys, thyroid damage, and other disorders.

Soy formula also contains 50 to 80 times the amount of manganese found in dairy formula or breast milk, toxic levels that can harm the infant’s developing brain, causing ADD/ADHD and other learning and behavioral disorders. Because ADD/ADHD has been linked to violent tendencies and crime, the California Public Safety Committee is now considering making soy infant formula illegal for the first six months of life except by prescription.

These and other known hazards of soy formula have led the Israeli Health Ministry, the Swiss Federal Health Service the British Dietetic Association and others to warn parents and pediatricians that soy infant formula should never be used except as a last resort. Although children and teenagers are less vulnerable than infants, their young bodies are still developing and prone to endocrine system disruption by soy.

Despite these and many other potential dangers, soy is still widely promoted as a health food – even as a cancer answer. While a few studies suggest that soy protein – or its phytoestrogens might help prevent cancer, far more studies show it to be ineffective or inconsistent. Some studies even show that soy can contribute to, promote or even cause cancer.

In February 2004, the Solae Company submitted a petition to the FDA requesting permission for the right to put a qualified soy-prevents-cancer health claim on packages. In its documents Solae claimed that “there is scientific agreement among experts” that such a health claim was warranted. In fact, no such consensus exists and numerous experts including scientists from the FDA’s own National Laboratory for Toxicological Research have warned of soy protein’s carcinogenic potential and the other health dangers that ensue from excess soy-food consumption.

The idea that scientists could even consider soy for a cancer claim is ludicrous on the face of it. Soy isoflavones after all, are listed as “carcinogens” in many toxicology and chemistry textbooks and have proven to be mutagenic, clastogenic and teratogenic in numerous studies. In addition, the modern industrial soy processing techniques used to make soy protein isolate, textured vegetable protein and other of the modern soy products popular with people on low-carb diets create toxic and carcinogenic residues.

In 2004 and 2005, the Weston Price Foundation and I submitted three detailed documents to the FDA that refuted Solae’s claims that soy prevents cancer. We showed the FDA that Solae was highly selective in its choice of evidence and biased in its interpretations. We reported on the fact that they had omitted many studies proving soy to be ineffective in preventing cancer, emphasized favorable outcomes in studies with mixed results and excused the results of the few unfavorable studies that they included to give the illusion of balance. Most importantly, we drew the FDA’s attention to the fact that Solae excluded many studies showing that soy protein can cause and accelerate the growth of cancer, particularly breast cancer.

In October 2005, Solae withdrew its petition. According to Solae officials, the withdrawing of their petition had “nothing to do” with the science but was a strategy designed to allow the company to “re-structure” their petition. However the FDA had advised Solae on at least one occasion that it had not convincingly established the claim that soy can prevent cancer and that it had failed to counter massive evidence that soy can cause, contribute to or accelerate cancer growth.

The FDA made a big mistake in 1999 when it sided with the soy industry and allowed a soy-and-heart-disease health claim. Today the FDA is under intense scrutiny because of the Vioxx debacle and could not afford to approve an unfounded soy-prevents-cancer health claim. Solae withdrew its petition because it knew that its science was unconvincing and that the FDA had no choice but to turn them down. The bottom line is that soy does not prevent cancer.

The soy industry held high hopes that a soy-prevents-cancer health claim would invigorate the industry and double sales of soy protein to $8.5 billion by 2007. Solae’s withdrawal of its FDA petition thus represents a major setback for industry. According to the recent market study Soyfoods: The U.S. Market 2005, soy food sales hit $4 billion in 2004 but climbed only 2.1 percent that year, the slowest growth for the industry since the early 1980s. The industry blames consumer “boredom” with soy products currently in the marketplace and consumer concerns about news reports, books and articles that have “questioned the health benefits of consuming soy-based food products.”


Kaayla T. Daniel, PhD, CCN is the author of the The Whole Soy Story