May 31, 2007 (Insidermedicine) Postmenopausal women who are eating a healthy diet may enjoy even greater protection from the cardiovascular damage caused by high blood pressure and elevated "bad cholesterol" by adding soy to their diet, according to the results of a study published in the May 28 issue of Archives of Internal Medicine.

Sixty healthy postmenopausal women – 12 of whom had high blood pressure – chowed down on the Therapeutic Lifestyle Changes diet that is recommended for lowering blood pressure, and which contains measured portions proteins, fat, and carbohydrate. Some weeks, the diet included soy nuts (dried-roasted soybeans) as a source of protein. The nuts also supplied components called isoflavones.

Measurements of blood pressure were taken each week during the eight-week study.

Francine Weltry of Boston's Beth Israel Deaconess Medical Center and colleagues found that all participants experienced a lowered blood pressure, which was especially pronounced in those whose blood pressure was elevated at the beginning of the study. As well, low-density cholesterol and a compound called apopliprotein B, which are both constituents of the artery-clogging "bad cholesterol" that contributes to hardening of the arteries, heart diseases, and stroke, were lowered in the women who had high blood pressure, but not in the other participants.

The effects, which were comparable to the use of blood pressure reducing drugs, were evident even though the diet lasted only eight weeks. The researchers feel that the benefical effects on blood pressure and cholesterol could be even more pronounced with a longer-term diet that incorporates soybeans.

The researchers think that the isoflavones in soybeans are the key ingredient. But, since earlier studies using individual soybean components including isoflavones as diet supplements have failed to find similar benefits, supplementing the diet with whole soybeans seems to be necessary.

The blood pressure changes seen in the women with high blood pressure "could have significant implications for reducing cardiovascular risk and death on a population basis," wrote the researchers.

Every year, the clogging of arteries by cholesterol build-up causes a heart attack or stroke in millions of North Americans. Reducing this risk in postmenopausal women through dietary soy may be a practical, safe, and inexpensive way to reduce blood pressure.

Reporting for Insidermedicine, I'm Dr. Petra Joller.