SOY FOODS AND NUTRITON
Eating soybean products is a relatively recent trend in the American diet.
How did this come about?
Soybeans contain 20% oil and this is what first attracted the interest of industry in America. After the oil was extracted, the manufacturer of the oil was left with a slush of the rest of the bean. Food companies developed ways to utilize this and turn it into food products. Tons of soybeans are mixed in an alkali solution, precipitated and washed in acid, and neutralized in another alkali bath. The process takes place in aluminum tanks, which leaches aluminum into the soy. Aluminum is a toxic heavy metal and is implicated in contributing to Alzheimer’s disease. The curds of soy are then spray dried at high temperatures to make protein powder. Applying high pressure and temperature to the powder turns it into textured vegetable protein. Processing byproducts in the soy include nitrates and nitrosamines (considered a carcinogen). Soy protein isolate is generally regarded as safe (GRAS) by the Food and Drug Administration but it has never been subjected to premarketing approval by the FDA. No tests or studies were done to show safety for such a highly processed food.
Current estimates are that 2/3 of soy grown in America is genetically modified. In 2000, 55% of soybeans planted was RRS (Roundup Ready Soy). This had a gene inserted into the DNA of the soy that allows the plant to resist the effect of being sprayed by Roundup. Roundup is a powerful toxic herbicide widely used on soybeans and other commercial crops.
Soy contains phytates, trypsin inhibitors, and hemagglutinin. The trypsin can block enzymes needed for protein digestion. The phytate may block uptake of minerals such as zinc, calcium, magnesium, copper and iron. Fermentation of soy into miso, tempeh and soy sauce reduces phytates, trypsin inhibitors and hemagglutinin. Soy is a frequent allergen.
The FDA approved a health claim in 1999 stating that 25 grams of soy protein per day may reduce the risk of heart disease. The research to support the claim is suspect and meta-analysis of the studies was done by Soy Protein International, a food industry group. Even if soy does lower cholesterol, the way in which it does may be bad for your hormone balance.
Phytoestrogens are plant chemicals that bind to estrogen receptors on cells. They are not steroids in their chemical structure so they do not behave as hormones when binding to cells. The actual effect of taking high does of plant phytoestrogens is simply unknown at this early stage in our knowledge.
Soy is not a miracle food. The problem is the way it is processed and refined. If you eat soy, eat small amounts of organically grown fermented products.
Daniel Blodgett MD