rom an email I got from Daily Health News

Soy For You

A few years ago, if you had asked me what the best "health food" in the world was, I probably would have said "soy."

Now I'm not so sure.

For years, we've been hearing that soy is a good source of protein, lowers cholesterol and reduces the risk for heart disease. There was also talk of soy protein having a protective effect against cancer. The reputation of soy still seems solid with mainstream doctors and dietitians. Lately, however, there have been rumblings of dissent in the nutritional community -- and some of these rumblings are very loud. Have we been oversold on soy?

To find out, I spoke with Kaayla Daniel, PhD, CCN, nutritionist and author of The Whole Soy Story: The Dark Side of America's Favorite Health Food (New Trends), who wrote three well-documented protests filed with the FDA regarding the proposed soy protein/cancer health claim. What I learned was disturbing.

MARKETING Versus SCIENCE

"Soy is not a health food, soy is not a panacea and soy has not even been proven safe," Dr. Daniel told me. "It's a triumph of marketing over real science." According to Dr. Daniel, the soy we are being sold in today's US market is a far cry from the soy eaten in Asian diets. "The type of food Asians eat is very different from what's appearing on the American table," she said. "While Asians do indeed eat small amounts of old-fashioned whole soy, they do not consume processed products made with soy protein isolate, texturized vegetable protein and soy oil. They rarely if ever consume soy shakes, energy bars, soy milk, soy burgers and other newly invented foods that use processed soy rather than 'the real deal'."

THE PROBLEMS WITH SOY

According to Dr. Daniel -- and to the growing number of soy detractors -- there are several other problems with soy...

First, it's not a particularly good source of protein. "Soy is very low in an essential amino acid called methionine, without which it can't be fully digested and utilized by the system," said Dr. Daniel. "It consistently scores low on almost all protein ratings except one, the protein digestibility corrected amino acid score (PDCAAS), which was set up as almost an 'affirmative action' rating system to make soy look better than it is." (See Daily Health News, October 10, 2005, for protein rating systems and the poor performance of soy.)

Second, soy contains phytates. Phytates are compounds found in beans, grains and seeds that bind toxic metals such as cadmium (a good thing), but also bind with minerals such as iron, zinc, calcium and magnesium, preventing their absorption (a bad thing). Phytates can cause iron deficiencies, leading to fatigue, lethargy, poor athletic performance and a weakened immune system. Iron deficiencies also can affect the thyroid, which in turn leads to weight gain.

Soy also contains protease inhibitors, compounds that inhibit important enzymes, such as trypsin, which are needed to digest protein. Protease inhibitors are the reason that soy protein, in all forms, is notoriously hard to digest and can badly stress the pancreas. "The commonly held notion that low levels of these protease inhibitors pose no threat to human health is simply untrue," said Dr. Daniel. Protease inhibitors have been linked to malnutrition and pancreatic disease. "While it's widely believed that cooking destroys them, it does not eliminate them completely."

Finally, there's the issue of phytoestrogens, which are plant estrogens found in soybeans. Phytoestrogens exert estrogenic effects directly and indirectly throughout the body. When eaten in sufficiently large quantities, "they can interfere with the production of thyroid hormones, disrupt menstrual cycles, contribute to infertility, even interfere with testosterone production in men, reducing their sex drive," Dr. Daniel told me. She concedes that soy sometimes reduces hot flashes but warns that the possible benefit is outweighed by proven risks to the thyroid, already a vulnerable gland for menopausal women, most often causing weight gain, fatigue and brain fog. Due to dangerous risks to ovarian hormone production, these phytoestrogen products derived from soy should not be used over the long run to treat PMS or symptoms of menopause.

SOY AND CANCER

As for the claim that soy prevents cancer, soy estrogens are listed as carcinogens in some chemistry textbooks. Dr. Daniel believes that compounds in soy may indeed have valid pharmaceutical uses in cancer treatment, but that's not the same as saying we should eat a lot of soy foods. According to Dr. Daniel, numerous studies actually show that soy can contribute to, cause and accelerate the growth of cancer. "Most alarmingly," she told me, "parents who feed their infants soy formula are unwittingly giving them the hormonal equivalent of three to five birth control pills a day, potentially interfering with brain and reproductive system development." The British Dietetic Association, Swiss Federal Health Service and other health authorities have warned parents and pediatricians against the use of soy formula, but in America, 25% of the bottle-fed market uses soy formula... and this number is growing.

Although most researchers are more moderate, believing that one or two portions of a good soy protein a day are probably fine, more and more nutritionists share Dr. Daniel's thinking. "There's no problem eating traditionally fermented products like miso in moderation, and even a little tofu once in a while," she told me, "but for people who want protein shakes, whey is a much better choice. The problem isn't the moderate consumption of soy -- it is the enthusiastic view of it as a perfect protein option for those looking to reduce their consumption of red meat and dairy products."

The answer? Moderation. Almonds anyone?