"Just imagine you could grow the perfect food. This food not only would provide affordable nutrition, but also would be delicious and easy to prepare in a variety of ways. It would be a healthful food, with no saturated fat. In fact, you would be growing a virtual fountain of youth on your back forty. This ideal food would help prevent, and perhaps reverse, some of the world's most dreaded diseases. You could grow this miracle crop in a variety of soils and climates. Its cultivation would build up, not deplete, the land. . . this miracle food already exists. . . It's called soy." This was written by Dean Houghton for The Furrow, a magazine published by the John Deere tractor company.
With 3/4 of all processed foods containing some form of soy in them these days, soybeans are quickly becoming a huge cash crop in the U.S., right behind corn, which is already in everything. Manufacturers have found ways to maximize the use of the bean, generating consumer goods from every part of the plant and by-products of all the steps of processing. Most of the public thinks of soy as a heath food, which is exactly how the soy industry wants it to be perceived. Is soy really good for you? Is it the miracle food that can reverse a host of disease states? This entry will attempt to shed some light on the issue.
A Brief History Of Soy Use
Soybeans first appeared for use during the Chou Dynasty (1134 - 246 BC) where they were not used for food, but frequently in crop rotation. Apparently the soy plant was initially used as a method of nitrogen fixing. The soybean did not serve as a food until the discovery of fermentation techniques, sometime late in the Chou Dynasty. The first soy foods were thus fermented products like tempeh, natto, miso and shoyu (soy or tamari sauce). At a later date, possibly in the 2nd century B.C., Chinese scientists discovered that a puree of cooked soybeans could be precipitated with calcium sulfate or magnesium sulfate (plaster of Paris or Epsom salts) to make a smooth pale curd - tofu or bean curd. The use of fermented and precipitated soy products soon spread to other parts of Asia, notably Japan and Indonesia. Although the highly flavored fermented products have elicited greater interest among scientists and epicures, it is the bland precipitated products that are most frequently used, accounting for approximately 90% of the processed soybeans consumed in Asia today. (The human genome adapts to new proteins, chemicals or toxins slowly. Since soy has only been used as a food source for a couple thousand years, it is not likely that our genes have adapted to massive soy consumption, given that grains have been consumed for roughly 10,000 years and celiac disease is still rampant in this country).
Large scale cultivation of the soybean in the United States began only after the Second World War. Most of the crop is made into animal feed and soy oil for hydrogenated fats (margarine and shortening). During the past 20 years, the industry has concentrated on finding markets for the byproducts of soy oil manufacture, including soy "lecithin", made from the oil sludge, and soy protein products, made from defatted soy flakes, a challenge that has involved overcoming consumer resistance to soy products, generally considered tasteless "poverty foods". "The quickest way to gain product acceptability in the less affluent society," said a soy industry spokesman, " ... is to have the product consumed on its own merit in a more affluent society." Hence the proliferation of soy products resembling traditional American foods: soy milk for cows milk, soy baby formula, soy yogurt, soy ice cream, soy cheese, soy flour for baking and textured soy protein as meat substitutes, usually promoted as high protein, low-fat, no cholesterol "healthfoods" to the upscale consumer increasingly concerned about his health. The growth of vegetarianism among the more affluent classes has greatly accelerated the acceptability and use of these ersatz products.
Is Soy Safe For Human Consumption?
- Soybeans contain potent enzyme inhibitors which block the action of trypsin and other enzymes needed for protein digestion. They can produce serious gastric distress, reduced protein digestion and chronic deficiencies in amino acid uptake. In precipitated products, enzyme inhibitors concentrate in the soaking liquid rather than in the curd. Thus in tofu and bean curd, these enzyme inhibitors are reduced in quantity, but not completely eliminated.
- Soybeans contain hemaglutinin, a clot promoting substance. Fermenting soybeans eliminates these substances.
- Soybeans are high in phytic acid or phytates. This is an organic acid, present in the bran or hulls of all seeds, which blocks the uptake of essential minerals such as calcium, magnesium, iron and especially zinc in the intestinal tract. The soybean has a higher phytate content than any other grain or legume that has been studied. Furthermore, it seems to be highly resistant to many phytate reducing techniques such as long, slow cooking. Only a long period of fermentation will significantly reduce the phytate content of soybeans. Thus fermented products such as tempeh and miso provide nourishment that is easily assimilated, but the nutritional value of tofu and bean curd, both high in phytates, is questionable. When precipitated soy products are consumed with meat, the mineral blocking effects of the phytates are reduced. Vegetarians who consume tofu and bean curd as a substitute for meat and dairy products risk severe mineral deficiencies.
- Much of soy today is genetically modified, which means that the gut has no history what-so-ever with such organisms. Therefore, the immune system, not recognizing such GM plants as foods, will treat such food antigens in the same manner it would an invasive virus, parasite, bacteria or fungi - it will try to eliminate it. Repeated exposure to such foodstuffs will sensitize the immune system, which may encourage autoimmune disorders.
- Soybeans contain isoflavones callled genistein and daidzein. Isoflavones are one of two primary groups of phytoestrogens, plant-based estrogen mimicking organic chemicals with antioxidant properties. The safety of these estrogen mimics is questionable at best. While most of the soy industry claims that these chemicals prevent certain types of cancer, studies have actually shown them to promote cancer. Women with current or past breast cancer should be aware of the risks of potential tumor growth when taking soy products. Some studies indicate a correlation between a soy-rich diet and a decrease in testosterone levels in men, and have linked soy to male infertility. The safety of phytoestrogens present in soy infant formula has been repeatedly called into question, with studies linking soy formula consumption to a number of developmental disorders, including early onset of puberty in girls, learning disorders, lack of development of male sexual organs, asthma, thyroid disorders and irritable bowel syndrome. The bottom line is that the phytoestrogens in soy are endocrine disruptors because they mimic a horomone naturally found in the body. The soy industry argues that the level of phytoestrogens that must be consumed to make their effect physiologically significant is astronimically high. This seems like a valid arguement until one considers just how prevalent soy is in the food supply, making this physiologically significant level of consumption easily attainable. Levels of physiological significance vary per the individual, with some people displaying thyroid dysfunction with as little as 38mg of ingested isoflavones/day, which is less than the amount found in two glasses of soy milk, two servings of tofu, or a handful of soy nuts.
- The process of producing soy protein isolate requires many processes that reduce the nutrient density and quality of the protein. In order to isolate the protein in soybeans from the carbohydrate and fatty acid components that naturally occur in the bean, they are first ground and subjected to high-temperature and solvent extraction processes to remove the oils. The resultant defatted meal is then mixed with an alkaline solution and sugars in a separation process to remove fiber. It is then precipitated and separated using an acid wash. Finally the resultant curds are neutralized in an alkaline solution and spray dried at high temperatures to produce high protein powder. This method destroys most of the anti-nutrients, but also denatures the proteins, rendering them difficult to digest and much reduced in effectiveness. The alkaline soaking solution produces a carcinogen, lysinealine, and reduces the cystine content, which is already low in the soybean. Lacking cystine, the entire protein complex of the soybean becomes useless unless the diet is fortified with cystine-rich meat, eggs, or dairy products.
Confused Yet?
If soybeans are so bad for you, then why is the soy industry relentlessly pushing the product as a health food, claiming numerous health benefits supposedly backed by scientific evidence? While I won't delve into the political and economical drivers behind this multi-billioin dollar industry, I will refute the most common argument FOR the safety of soy consumption: How can soy be bad for you if Asians have been and continue to consume massive quantities of the bean and all its products, yet display low incidence of most of the maladies that soy is supposed to cause?
Soy proponents claim that soy is a staple in Asia. A "staple" is defined as a major commodity, one that provides a large portion of calories in the diet, such as rice and fish in Japan, or rice and pork in China. The Japanese consume 150 pounds of fish per person per year, or almost one-half pound per person per day. A 1977 dietary survey in China determined that 65 percent of calories came from pork, including the pork fat used in cooking. By contrast, overall consumption of soy in Asia is surprisingly low. The average soy consumption in China is about 10 grams or 2 teaspoons per day. Levels are somewhat higher in Japan, averaging about 50 grams or 1/4 cup per day. In both countries, soy is used as a condiment or for flavoring, and not as a substitute for animal foods. Seafood and seaweed in the Japanese diet provide sufficient iodine to counteract the negative effects of the isoflavones in soy. The majority of soy products consumed in Asia are of the fermented type, containing the least amount of anti-nutrients. These levels of consumption amount to approximately 28mg of soy isoflavones per day. The lowest amount of isoflavones shown to cause endocrine dysfunction after just one month of consumption in American women is 45mg per day.
This post is by no means an exhaustive review of soy consumption and its relative risks. Information (backed by peer reviewed studies) is plentiful and free on the net. Here are a few resources where I pooled my information from that provide more information about soy than you ever thought you wanted to know. I urge you to educate yourself and come to your own conclusions:
http://www.mercola.com/article/soy/index.htm
http://www.westonaprice.org/soy/index.html
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