Soybean Glycine max
The soybean is a legume, a distinction it shares with lentils, peas, beans and peanuts and was held in such high regard that it was considered one of the five sacred grains along with barley, wheat, millet (hay) and rice by the Chinese.
Fermentation techniques led to the invention of soy sauce, miso, tempeh and natto. Fermented soybeans contain less of the active phytochemicals found in the whole bean.
Soybeans are a nutrient-rich food and best plant source of protein. It also contains unsaturated fat, fiber, B-vitamins, folic acid, potassium, calcium, zinc, and iron. As with all legumes, soy is a great source for iron and does not contain cholesterol.
Soybean is the only botanical food that contains all the essential amino acids. Soybeans are lactose free and are therefore used as a substitute for dairy products for lactose intolerant people.
Soybeans contain fructooligosaccharides (FOS). These are the carbohydrates that nourish intestinal bacteria.
Soybeans have a low glycemic index, which delays the body’s insulin response. The delayed response stabilizes blood sugar levels with fewer mood swings.
Soybeans contain omega-3 fatty acids and its oil is over 80 percent unsaturated.
Soybeans improve the lipoprotein profile by lowering total triglyceride levels. As a natural wonder drug, soybeans lower the lousy or LDL fraction and raise the healthy or HDL fraction.
Soybeans contains the anti-cancer isoflavone, genestein.
Soybeans also contains phytoestrogens, which are believed to reduce the risk and spread of prostate cancer.
Soybeans contain the highest amount of isoflavones among foods. These compounds are considered phytoestrogens and are structurally similar to the more active, human estrogens.
The phytoestrogens of soybeans are the isoflavones, genestein, daidzein and glycitein. In their natural state as part of the soybean, these compounds are always bound to glucose and are termed glycosides. Once injested, they are converted into their active or aglycone (non-glycosidic) form by intestinal bacteria.
The isoflavones and phytoestrogens of soybeans are thought to reduce the incidence of breast cancer. This anti-cancer property is associated primarily with the non-fermented soy products, tofu and soymilk, and not with fermented soy products like nato and miso.
The isoflavone content of soybeans depends on the method used to isolate it. Soy protein isolates prepared by an ethanol wash process causes the lost of most of their isoflavones, while those prepared by the aqueous wash processes retains them.
The isoflavones and phytoestrogens of soy are hormone-like compounds with weak estrogenic and antioxidant activity. These compounds are believed to reduce the incidence of breast and prostate cancer by interfering with their metabolism.
On the cellurar level, soybean’s isoflavones act by inhibiting a cancer’s cells enzyme systems and retarding its blood supply.
On a molecular level, soybean’s isoflavones inhibit tyrosine kinases and inactivates DNA topoisomerase II. Soybean’s isoflavones are anti-angiogenesis compounds and are thought to arrest cell growth by interfering with signal transduction of one or more of a series of cascading reactions.