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Soy Isoflavone Concentrate

Soy isoflavone concentrate is taken from the beans of the soy plant.

The soybean contains several medicinally useful chemicals, including isoflavones and lecithin. The isoflavones most recognized as beneficial are daidzein and genistein, and the closely related compounds daidzin and genistin. These substances have been well researched for their antioxidant and phytoestrogenic properties.

Soy isoflavones are used medicinally primarily because of their estrogen-regulating properties.

Benefits of soy isoflavones for specific health conditions include the following:

  • Alzheimer's disease. Estrogen is believed to slow the production of amyloid plaques in the brain and help preserve memory, two problems closely associated with Alzheimer's disease. Thus, soy isoflavones may help slow the progress of Alzheimer's disease.
  • Atherosclerosis. Soy isoflavones prevent the formation of atherosclerotic plaques within blood vessels.
  • Cancer. Because of its estrogen like properties, soy has been shown to reduce the risk of hormone-dependent cancers, such as breast and prostate cancers, as well as the risk of other types of cancer. The similarity of soy isoflavones to the human hormone estrogen allows isoflavones to attach to estrogen receptors in human cells. This blocks actual human estrogen from doing the same. The isoflavones are just different enough from estrogen, however, that they do not stimulate cells as estrogen does. This keeps estrogen away from cells that are sensitive to estrogen, especially cancerous cells in the bladder, breast, colon, prostate, and skin.
    Daidzein is one such estrogen-blocking isoflavone. It locks out estrogen from breast-cancer cells without stimulating the cells to reproduce. It also fights cancer by causing immature tumor cells to differentiate, or mature into forms that have normal life spans and are then replaced. Daidzein has been shown to be very potent in forcing differentiation of human leukemia cells and of melanoma cells, even when absorbed in very low concentrations.
    Finnish researchers conducted decades of exacting studies to explain why the people of Japan enjoy lower rates of breast, ovarian, prostate, and other cancers. They identified genistein as the common denominator. Genistein is especially valuable in reversing cancer risk associated with certain kinds of obesity in women. Women who are physically inactive and have a genetic tendency toward diabetes often develop insulin resistance, a condition in which the body is forced to produce more and more insulin to transport glucose to the cells where it is needed. In addition to regulating blood sugar, insulin facilitates the transport of fat into fat cells, and fatty tissue produces estrogen. Thus, insulin indirectly activates estrogen and progesterone receptors, an action that stimulates the growth of cells, including estrogen-activated cancer cells. Since genistein blocks estrogen from its receptors on cells, it helps fight the cancer-promoting effects of excess estrogen production.
    Genistein counteracts cancer development on several levels. It deactivates a harmful protein called tyrosine protein kinase, a key player in stimulating cell growth. This keeps cancer cells from multiplying. Genistein also affects other key enzymes involved in the cancer-formation process. Like daidzein, genistein causes cancer cells to differentiate, stopping wild multiplication. In addition, genistein stops the process by which tumors develop their own systems of blood vessels. This action deprives cancer cells of nutrients and oxygen, keeping them small. There is also evidence, at least in the case of certain kinds of lung cancer, that genistein complements the action of the gene p53, a "patrol gene" that deactivates cancer cells.
  • Diabetic retinopathy. The genistein content of soy isoflavones allows them to fight the development of diabetic retinopathy, an eye disorder that is a complication of diabetes.
  • Fracture, menopause-related problems, and osteoporosis. Through their estrogenic action, soy isoflavones help move calcium from the bloodstream into the bones, strengthening their resistance to fracture. The mild estrogenic activity of soy isoflavones may ease menopause symptoms for some women, without creating estrogen-related problems, as well as having a positive effect in the prevention of osteoporosis. A series of clinical trials around the world has established that soy isoflavones are a useful and safe alternative to estrogen therapy in treating low bone mass or osteoporosis in women who have passed menopause.
  • Psoriasis. The genistein in soy reduces the formation of keratin, a skin protein associated with psoriasis.

The easiest way to get soy isoflavones is by taking soy isoflavone concentrate. Soy germ also can be used, as can cooked soybeans, miso, or tofu (soybean curd). Soy isoflavones are also found in the herb kudzu. Of readily available soy foods, roasted soybeans have the highest isoflavone content, about 167 milligrams for a 3.5-ounce serving. Tempeh is next, with 60 milligrams, followed by soy flour with 44 milligrams. Processed soy products such as soy protein and soymilk contain about 20 milligrams per serving. Although the optimum dosage of isoflavones obtained from food is not known, one study found that ingesting 62 milligrams of isoflavones daily is sufficient to reduce cholesterol. Further, we know that Japanese women eat up to 200 milligrams of isoflavones from soy foods daily.

Although it is not a purely herbal product, ipriflavone, a chemically altered form of soy isoflavones, is a better choice for preventing and treating osteoporosis, and for preventing bone fractures in weight lifters and participants in contact sports. Clinical testing in Japan has found that treatment with ipriflavone, even without supplemental calcium, prevents bone loss better than calcium supplementation alone.

Because isoflavones work somewhat like estrogen, there are concerns that they may not be safe for women who already have breast cancer. Preliminary studies and reports have raised concerns that intensive use of soy products by a pregnant woman could exert a hormonal effect that has an impact on the developing fetus. Soy isoflavones could theoretically interfere with the action of oral contraceptives, although studies have not confirmed this.

Soy products may impair thyroid function or reduce absorption of thyroid medication, at least in children. People with impaired thyroid function should use soy in moderation or under medical supervision.

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