Soy and Your Heart
by Dana Denis, MSPH., RD (topic expert: nutrition) Tofu, soy burgers, miso, edamame, soy milk and soy nuts. Have you been adding these to your diet in an effort to reduce your risk of heart disease or cancer? But now you are hearing this may not be the case. Is this still the recommendation of the experts? What's new and what's changed? In 1999, the US Food and Drug Administration approved the use of labeling foods that contain at least 6.25 grams of soy protein per serving as protective against coronary heart disease (1). This was after a thorough analysis of the research at that time that showed replacing animal protein with soy protein reduced total cholesterol and LDL cholesterol (bad cholesterol). This was also supported by studies that showed that Asian countries, which consumed high amounts of soy, had lower incidence of heart disease and hypercholesterolemia. However, there are many differences between Western and Asian countries besides soy intake. Since that time, several more studies have been completed that evaluated both soy protein and soy's phytoestrogen, isoflavone and their effect on heart disease, blood pressure, menopausal symptoms, osteoporosis and cancer. (Phytoestrogens act like estrogen and so will compete with estrogen and reduce the harmful effects associated with estrogen to produce beneficial effects.) In 2006, the American Heart Association has completed an analysis of 22 new research studies and reported these findings in their publication, Circulation (2). This is what they found: Heart Disease Soy protein or isoflavones were not able to consistently lower cholesterol or LDL cholesterol. Some studies showed a very small reduction with large amounts of soy. There was no effect found on HDL cholesterol (good cholesterol), triglycerides or blood pressure; therefore if there is a beneficial effect it is probably minimal. Any beneficial effect is thought to be due to the soy protein and not the content of the phytoestrogens in soy - isoflavones. Menopausal Symptoms Soy isoflavones behave like estrogen to a small degree, so it was thought they could help with menopausal symptoms, such as hot flashes and reduction in bone density. The research did not support a reduction of hot flashes. The studies of bone density that have been completed so far are too small or too short to provide any conclusive evidence - some report a benefit and others find none. There is definitely a need for more studies in this area. Cancer Again, due to the fact that isoflavones have a slight estrogen effect, it is thought that they may reduce the chance of developing certain types of cancers, such as cancers of the breast, uterine endometrium and prostate. The research could not support the conclusion that isoflavone reduced risk or enhanced treatment of cancer. In fact, some studies actually showed a potential increased risk with high soy intake. Because of this, the American Heart Association does not recommend taking isoflavone or soy supplements. Current soy and breast cancer research is focusing on some preliminary data that suggests that eating a diet high in soy during childhood or early adolescence may have a protective effect. So soy is not the "magic bullet" to cure heart disease and cancer, but is it still beneficial? The good news is that soy foods contain high amounts of polyunsaturated fats, fiber, vitamins and other nutrients, as well as being low in saturated fat. This makes it a perfect heart healthy food to be incorporated into any diet, especially when replacing animal protein. So expand your culinary experience. - Instead of the fatty all beef burger, try a soy burger;
- Include tofu instead of meat in your next stir-fry or pasta dish;
- Try snacking on a few soy nuts or edamame (soy beans) instead of chips or crackers loaded with fat and trans fats;
- Order soy milk instead of whole fat milk in your next latte.
You will be doing your heart a favor and - you may be pleasantly surprised! Footnotes: - US Food and Drug Admin study
- Circulation
|