Nexus - 0703 - New Times Magazine-pages

Page Content (OCR)

Soy also contains goitrogens—substances that depress thyroid SPI is not something you can make in your own kitchen. function. Production takes place in industrial factories where a slurry of Soybeans are high in phytic acid, present in the bran or hulls of is first mixed with an alkaline solution to remove fibre, all seeds. It's a substance that can block the uptake of essential then precipitated and separated using an acid wash, and, finally, minerals—calcium, magnesium, copper, iron and especially neutralised in an alkaline solution. Acid washing in aluminium zinc—in the intestinal tract. Although not a household word, tanks leaches high levels of aluminium into the final product. The phytic acid has been extensively studied. There are literally hun- resultant curds are spray-dried at high temperatures to produce a dreds of articles on the effects of phytic acid in the current scien- high-protein powder. A final indignity to the original soybean is tific literature. Scientists are in general agreement that grain- and high-temperature, high-pressure extrusion processing of soy pro- legume-based diets high in phytates contribute to widespread min- tein isolate to produce textured vegetable protein (TVP). eral deficiencies in Third World countries. Analysis shows that Much of the trypsin inhibitor content can be removed through calcium, magnesium, iron and zinc are present in the plant foods high-temperature processing, but not all. Trypsin inhibitor con- eaten in these areas, but the high phytate content of soy- and tent of soy protein isolate can vary as much as fivefold.’ (In rats, grain-based diets prevents their absorption. even low-level trypsin inhibitor SPI feeding results in reduced The soybean has one of the highest phytate levels of any grain weight-gain compared to controls.”) But high-temperature pro- or legume that has been studied," and the phytates in soy are cessing has the unfortunate side-effect of so denaturing the other highly resistant to normal phytate-reducing techniques such as proteins in soy that they are rendered largely ineffective.” That's long, slow cooking."’ Only a long period of fermentation will sig- why animals on soy feed need lysine supplements for normal nificantly reduce the phytate content of soybeans. When precipi- growth. tated soy products like tofu are consumed Nitrites, which are potent carcinogens, are with meat, the mineral-blocking effects of the formed during spray-drying, and a toxin called phytates are reduced.'* The Japanese tradi- . ysinoalanine is formed during alkaline pro- tionally eat a small amount of tofu or miso as Soy contains cessing.“ Numerous artificial flavourings, part of a mineral-rich fish broth, followed by goitrogens—substances particularly MSG, are added to soy protein iso- a serving of meat or fish. ate and textured vegetable protein products to Vegetarians who consume tofu and bean that depress thyroid mask their strong "beany" taste and to impart curd as a substitute for meat and dairy prod- function. the flavour of meat.” ucts risk severe mineral deficiencies. The In feeding experiments, the use of SPI results of calcium, magnesium and iron defi- increased requirements for vitamins E, K, D ciency are well known; those of zinc are less Soybeans are high in and B12 and created deficiency symptoms of so. . . calcium, magnesium, manganese, molybde- Zinc is called the "intelligence" mineral phytic acid, a substance num, copper, iron and zinc.*® Phytic acid pea i nel or otina decloment that blocks the uptake ramsinng in thes soy product greatly system. It plays a role in protein synthe- of essential minerals— animals fed SPI develop enlarged organs, sis and collagen formation; it is involved i i particularly the pancreas and thyroid in the blood-sugar control mechanism calcium, magnesium, gland, and had increased deposition of and thus protects against diabetes; it is copper, Iron and fatty acids in the liver.” especially zinc—in the intestinal tract. needed for a healthy reproductive sys- Yet soy protein isolate and textured tem. Zinc is a key component in numer- vegetable protein are used extensively in ous vital enzymes and plays a role in the school lunch programs, commercial immune system. Phytates found in soy baked goods, diet beverages and fast food products interfere with zinc absorption products. They are heavily promoted in more completely than with other miner- Third World countries and form the basis als.'!° Zine deficiency can cause a of many food giveaway programs. "spacey" feeling that some vegetarians In spite of poor results in animal feed- may mistake for the "high" of spiritual ing trials, the soy industry has sponsored enlightenment. a number of studies designed to show that soy protein products Milk drinking is given as the reason why second-generation can be used in human diets as a replacement for traditional foods. Japanese in America grow taller than their native ancestors. An example is "Nutritional Quality of Soy Bean Protein Isolates: Some investigators postulate that the reduced phytate content of Studies in Children of Preschool Age", sponsored by the Ralston the American diet—whatever may be its other deficiencies—is Purina Company.* A group of Central American children suffer- the true explanation, pointing out that both Asian and Western ing from malnutrition was first stabilised and brought into better children who do not get enough meat and fish products to coun- health by feeding them native foods, including meat and dairy teract the effects of a high phytate diet, frequently suffer rickets, products. Then, for a two-week period, these traditional foods stunting and other growth problems.” were replaced by a drink made of soy protein isolate and sugar. All nitrogen taken in and all nitrogen excreted was measured in SOY PROTEIN ISOLATE: NOT SO FRIENDLY truly Orwellian fashion: the children were weighed naked every Soy processors have worked hard to get these antinutrients out. morning, and all excrement and vomit gathered up for analysis. of the finished product, particularly soy protein isolate (SPI) The researchers found that the children retained nitrogen and that which is the key ingredient in most soy foods that imitate meat their growth was "adequate", so the experiment was declared a and dairy products, including baby formulas and some brands of _ success. soy milk. Whether the children were actually healthy on such a diet, or Soy contains a on SOY PROTEIN ISOLATE: NOT SO FRIENDLY Soy processors have worked hard to get these antinutrients out of the finished product, particularly soy protein isolate (SPI) which is the key ingredient in most soy foods that imitate meat and dairy products, including baby formulas and some brands of soy milk. APRIL —- MAY 2000 NEXUS - 21