From the Guidelines
Soy consumption does not increase the risk of cardiovascular disease, and in fact, may have a beneficial effect on heart health when consumed as part of a balanced diet. The American Heart Association's science advisory on soy protein, isoflavones, and cardiovascular health, published in Circulation in 2006 1, suggests that soy products such as tofu, soy butter, and soy nuts can be beneficial to cardiovascular and overall health due to their high content of polyunsaturated fats, fiber, vitamins, and minerals, and low content of saturated fat. Some key points to consider when consuming soy products include:
- Using soy foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health
- Soy protein may be used to increase total dietary protein intake and to reduce carbohydrate or fat intake
- The evidence favors soy protein rather than soy isoflavones as the responsible nutrient for any potential cardiovascular health benefits
- No benefit is evident on HDL cholesterol, triglycerides, lipoprotein(a), or blood pressure from consuming soy protein or isoflavones
- A very large amount of soy protein, more than half the daily protein intake, may lower LDL cholesterol by a few percentage points when it replaces dairy protein or a mixture of animal proteins, as noted in the study 1.
From the Research
Soy Consumption and Cardiovascular Disease Risk
- The relationship between soy consumption and cardiovascular disease risk is complex and has been studied extensively 2, 3, 4, 5, 6.
- Some studies suggest that soy consumption may be associated with a lower incidence of cardiovascular disease, particularly in Asian populations 3.
- A meta-analysis of observational studies found a significant negative association between soy intake and risk of cardiovascular disease, including stroke and coronary heart disease 3.
- However, other studies have found inconsistent or inadequate evidence to support the suggested health benefits of consuming soy protein or isoflavones 2, 4.
Mechanisms and Components
- Soybeans contain various components, including isoflavones, lecithins, saponins, and fiber, which may improve cardiovascular health through independent mechanisms 5.
- The hypocholesterolemic effect of soy is well-documented, and soy protein has been approved for a health claim relating to reduced risk of cardiovascular disease 2, 5.
- Isoflavones, in particular, have been shown to have a favorable effect on cardiovascular health, with higher intake associated with decreased risk of mortality from all causes, cancers, and cardiovascular diseases 6.
Population-Specific Findings
- A prospective cohort study of 0.5 million individuals found that soy product consumption was inversely associated with mortality from acute myocardial infarction in people without a history of cardiovascular disease 4.
- However, among people with a history of cardiovascular disease, higher soy product consumption was not associated with cardiovascular mortality 4.
- Another study found that soy and its isoflavones may favorably influence risk of mortality, particularly in relation to breast cancer and ischemic cardiovascular diseases 6.