A substantial body of research – more than 80 human trials over the past 30 years – has been conducted investigating the effects of soy intake on cardiovascular health, with the general finding being that soy protein can help lower LDL (bad) cholesterol between at least 3 and 5 percent. Even these modest reductions have considerable relevance, since each 1 percent drop in LDL is associated with a 2 to 4 percent decrease in heart disease risk.^{1 2}

The American Heart Association’s nutrition guidelines state that using soy protein as a replacement for animal protein products that are high in saturated fat may provide cholesterol-lowering benefits and that “the consumption of soy protein containing isoflavones, along with other heart-healthy diet modifications, is recommended for those high-risk populations with elevated total and LDL cholesterol.” ³

In fact, in 1999 the Food and Drug Administration (FDA) issued the health claim that consuming 25 grams of soy protein per day, as part of a diet that is low in saturated fat and cholesterol, may reduce the risk of heart disease.

While soy is not medicine, it is a nutrient-rich food that can be an important part of a balanced diet. The degree of cholesterol reduction generally found with soy is comparable to that of other wholesome foods that carry an FDA heart-health claim, such as oatmeal. They are both foods that the FDA continues to advocate for use as part of a balanced diet to promote heart health.

The hypocholesterolemic effects of soy protein began gaining widespread attention⁴ in 1995, when a meta-analysis by Anderson et al. proved that soy protein helped reduce serum cholesterol levels in 34 of 38 trials.⁵

Studies have shown that the reduction in cholesterol due to soy consumption is greater than that achievable on a low-saturated fat diet alone, since in most trials, subjects were on low-fat diets prior to participation in the trials. And, while soy protein alone may not lower cholesterol to a target goal in overtly hypercholesterolemic individuals, it can provide effects similar to that of soluble fiber.⁶

Most recently, the American Journal of Clinical Nutrition published a study⁷ that measured the effect of several soy protein sources vs. animal protein on many cardiovascular disease risk factors, including LDL cholesterol levels, by examining the effect of four diets (i.e., animal protein, whole soybeans, soy flour and soymilk). The study concluded that a diet of soymilk showed a significant reduction (4 percent) in LDL cholesterol compared to all other groups. The soymilk used in this experiment was Silk.

Soy Fact

Find easy and tasty ways to add soy foods to your everyday cooking.