PULLMAN, Wash.--Soy isoflavones modulate immune function in healthy postmenopausal women, likely due to their estrogenic and antioxidant properties, according to a study published in the American Journal of Clinical Nutrition (83, 5:1118-25, 2006).
Scientists from Washington State University randomly assigned postmenopausal women aged 50 to 65 years (n = 52) to one of three experimental groups: 1) control, 706 mL/d dairy milk plus a placebo supplement; 2) soymilk, 71.6 mg/d isoflavones derived from 706 mL/d soymilk, plus a placebo supplement; and 3) supplement, 70 mg/d isoflavones in a supplement plus 706 mL/d. Plasma and 24-hour urine samples were obtained at baseline and at 16 weeks and assayed for immune variables including lymphocyte subsets, cytokine production and markers of inflammation and oxidative damage. Isoflavone supplementation resulted in higher B cell populations and lower plasma concentrations of 8-hydroxy-2-deoxy-guanosine, an oxidative marker of DNA damage. The researchers concluded soymilk and supplemental isoflavones modulate B cell populations and appear to be protective against DNA damage in postmenopausal women.
