Women and Heart Disease

It is often a surprise to learn that a leading cause of death for women is coronary heart disease ^{15 , 16} . Soy foods operate on a number of levels to reduce heart disease risk. One of those is the ability to reduce blood cholesterol (for further detail on this please, refer to the section on heart disease). Various researchers have studied the cholesterol-lowering ability of soy protein, specifically in women.

Dr. Scott Washburn ⁷ from Wake Forest University showed in peri-menopausal women that 20g of soy protein with isoflavones significantly reduced total cholesterol and LDL-cholesterol compared to the control (carbohydrate) diet. This beneficial effect occurred when the soy protein was consumed in one daily dose or split over two daily doses.

A study in pre-menopausal vegetarian women by Dr. Aedin Cassidy and colleagues at the Dunn Clinical Nutrition Centre in Cambridge ¹⁷ , showed that replacing animal protein with 60g of textured vegetable protein (TVP or 'soy mince') resulted in a significant 9% reduction in total cholesterol levels. In a separate part of this study, a significant improvement in the ratio of LDL:HDL cholesterol (an indicator of heart disease risk) occurred when 28g of TVP was added to the daily diet.

The study mentioned previously, with postmenopausal women placed on the TLC diet with the addition of half a cup of soy nuts daily, similarly found a significant reduction in LDL-cholesterol and apolipoprotein B levels by 11 % and 8 %, respectively. This was also the first study to directly compare the effects of whole soy foods in people with high and normal blood pressure (BP). Interestingly, the addition of the soy food on top of the already healthy diet for heart disease prevention, lowered systolic and diastolic BP by 9.9 % and 6.8 %, respectively, in women with hypertension and 5.2 % and 2.9 %, respectively, in those with normal blood pressure ⁶ . These results are comparable with those seen with antihypertensive drugs. Further subdivision of the women with 'normal' BP into prehypertensive (now defined as systolic blood pressure of 120-139 mm Hg) and normotensive groups showed that both experienced significant reductions in their BP. Importantly, the 'at risk' prehypertensive group experienced a drop in their systolic and diastolic BP of 5.5 % and 2.7 %, respectively. These findings are very important as the prevalence of hypertension increases with age, and women with hypertension have a 4-fold risk of coronary heart disease. The results have significant implications for reducing cardiovascular disease risk by using a dietary approach that includes soy foods, on top of a high plant food containing diet (known as DASH), salt and alcohol reduction and other lifestyle modifications such as weight reduction.