Cellular damage resulting from oxidative stress is believed to be a major contributor of cardiovascular disease through LDL cholesterol oxidation and to cancer through DNA strand breaks that may lead to mutations. In humans, isoflavones have been found to prevent LDL oxidation in vivo and to inhibit DNA damage in vitro. Studies indicate the antioxidant and anti-proliferative properties of soy isoflavones afford protection against oxidative stress.
A 2006 study evaluated the effects of soy isoflavones in soymilk (71 mg day) and in a dietary supplement (70 mg day) on markers of immunity and oxidative stress in postmenopausal women. An additional group of women in the study (control group) received a milk like supplement or a placebo dietary supplement.
Plasma concentrations of 8-OHdg* reflect oxidative damage to DNA, and concentrations increase during repair of DNA. The postmenopausal women in the isoflavone treatment groups had significantly lower concentrations of 8-OHdg than did the control group. B cells are small white blood cells that stimulate immune defenses. Isoflavone intervention also resulted in higher B cell populations.
a bit more about soy isoflavones . . .
Isoprostanes are compounds produced by the peroxidation of phospholipids in tissues, and elevated concentrations have been found in plasma and urine during periods of oxidative stress. An additional study found dietary soy isoflavones (34 mg genistein & 21 mg daidzein/equol) decreased f2-isoprostane** concentrations and increased resistance of LDL cholesterol to oxidation.
Soy isoflavones seem to behave like antioxidants and afford a degree of protection against diseases resulting from oxidative damage. When enriching ones diet with soy isoflavones, it is important to find (organic) soymilk, tofu and supplements manufactured from Non-GMO Soy: natural soybeans with no genetic modification.
*8-hydroxy-2-deoxy-guanosine
**8-epi-prostaglandin F2a
Sources:
Soy isoflavones modulate immune function in healthy postmenopausal women
Tracy A Ryan-Borchers, Jean Soon Park, MD's
American Journal of Clinical Nutrition, Vol. 83, No. 5, 1118-1125, May 2006
Isoflavone Phytoestrogens consumed in Soy Decrease F2-isoprostane Concentrations and Increase Resistance of Low Density Lipoprotein to Oxidation in Humans.
Helen Wiseman, James D O'Reilly MD's
American Journal of Clinical Nutrition, Vol. 72, No. 2, 395-400, August 2000
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