A new study to be published in the November 2011 issue of Stroke reveals some promising data on the positive effects of soy protein reducing the progression of clogged arteries in women who were within five years of menopause. This study was the largest and longest randomized controlled human study conducted to-date that directly investigated the efficacy of isolated soy protein consumption on the progression of atherosclerosis.

"These results are consistent with what we have learned through research conducted over the past decade," said Howard N. Hodis, M.D., 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 5-6 years of menopause."

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

Excellent compliance was observed for this study as determined by package and bar count (86.5 percent for placebo and 91.0 percent for isolated soy protein). Compliance was confirmed by plasma and urine isoflavone measurements.

"The high compliance suggests that the clinical study products provided by Solae were very palatable and were not associated with any significant adverse effects as confirmed by the data," said Elaine Krul, Ph.D., nutrition discovery lead, Solae.

Subjects in this study were 'healthy' with no previous signs of cardiovascular disease which may explain the lack of significant reduction in plasma lipids that is seen in persons with higher plasma lipid levels.

"This study also showed a significant increase in HDL cholesterol in participants consuming isolated soy protein," said Krul. "The results of this study reinforce that soy protein can provide health benefits for the healthy aging market segment."

The study was conducted between 2004 and 2009. It was a double-blind, placebo-controlled parallel-design study of 350 postmenopausal women aged 45-92 years without diagnosed diabetes or heart disease that were recruited in Greater Los Angeles.