title: Soy isoflavones modulate immune function in healthy postmenopausal women.
abstract: BACKGROUND
  The immune system may be compromised after menopause because of the effects of aging and diminishing concentrations of estrogen, an immune-modulating hormone. Isoflavones, plant-derived compounds with estrogenic and antioxidant properties, may offer immunologic benefits to women during this stage of life.
  
  
  OBJECTIVE
  The objective of this study was to evaluate the effects of soy isoflavones, both in soymilk and in supplement form, on markers of immunity and oxidative stress in postmenopausal women.
  
  
  METHODS
  Postmenopausal women aged 50-65 y (n = 52) enrolled in this 16-wk double-blind, placebo-controlled trial were randomly assigned to 1 of 3 experimental groups: 1) control, 706 mL cow milk/d plus a placebo supplement; 2) soymilk, 71.6 mg isoflavones derived from 706 mL soymilk/d plus a placebo supplement; and 3) supplement, 70 mg isoflavones in a supplement plus 706 mL cow milk/d. Plasma and 24-h urine samples were obtained at baseline and at 16 wk. Immune variables included lymphocyte subsets, cytokine production, and markers of inflammation and oxidative damage.
  
  
  RESULTS
  Isoflavone intervention in postmenopausal women resulted in higher (P < 0.05) B cell populations and lower (P < 0.05) plasma concentrations of 8-hydroxy-2-deoxy-guanosine, an oxidative marker of DNA damage. Isoflavone treatment did not significantly influence concentrations of interferon gamma, interleukin 2, tumor necrosis factor alpha, or C-reactive protein in plasma or of 8-isoprostane in urine.
  
  
  CONCLUSIONS
  Soymilk and supplemental isoflavones modulate B cell populations and appear to be protective against DNA damage in postmenopausal women.
authors: Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376, USA.
authors: Tracy A
authors: TA
authors: Ryan-Borchers
authors: Jean Soon
authors: JS
authors: Park
authors: Boon P
authors: BP
authors: Chew
authors: Michelle K
authors: MK
authors: McGuire
authors: Lisa R
authors: LR
authors: Fournier
authors: Kathy A
authors: KA
authors: Beerman