Soy Protein Reduces Atherosclerosis in Postmenopausal Women

LOS ANGELESPostmenopausal women who consume a diet rich in soy protein may reduce the progression of atherosclerosis by 16%, according to a new study published in the journal Stroke. The reduction increases to 68% in women who experienced menopause within the past five years.

To investigate the efficacy of isolated soy protein consumption on the progression of atherosclerosis, researchers at the USC Keck School of Medicine conducted a study on 350 postmenopausal women aged 45-92 years who did not have diabetes or heart disease. Study participants were randomized to two evenly divided daily doses of 25 g soy protein containing 91 mg aglycon isoflavone equivalents or placebo for 2.7 years.

The progression rate of carotid artery intima-media thickness (CIMT) trended to be 16% lower on average in the isoflavone-containing soy protein group compared with the placebo group. In women who had experienced menopause within the past five years, isolated soy protein consumption was associated with a significant 68% reduction in CIMT progression compared to those consuming the placebo. The researchers also observed a significant increase in HDL cholesterol in participants consuming isolated soy protein.

"These results are consistent with what we have learned through research conducted over the past decade," said Howard N. Hodis, MD, USC Keck School of Medicine and lead author of the study. "The literature demonstrates that there is a 'window of opportunity' of a potential beneficial effect on coronary heart disease for products that bind to the estrogen receptor including hormone-replacement therapy, soybean isoflavones or selective estrogen receptor modulators (SERMs) when initiated in women within  five to six years of menopause."