The New Low-Cholesterol Diet: Soy Protein

Versatile soy protein may lower bad fats floating in your bloodstream

By R. Morgan Griffin
WebMD Weight Loss Clinic - Feature

Reviewed By Cynthia Haines, MD

Soy protein can be a meal, a side dish, a snack or a drink. Made from the soybean, it's a staple of Asian diets. Yet it's largely been the butt of jokes about hippies and vegans - until recently. Today, research shows that if you are a man - or a woman - with rising cholesterol, it's time to take soy more seriously.

How Does Soy Protein Help?

A number of studies show that soy protein may lower "bad" LDL cholesterol and triglycerides without lowering "good" HDL cholesterol. Researchers aren't exactly sure how soy protein does this. It may be a combination of the effect of the protein and natural chemicals in soy called isoflavones.

What's the Evidence?

There have been many studies of the effects of soy on cholesterol. One major 1995 article published in the New England Journal of Medicine found that replacing animal protein with soy protein could lower levels of total cholesterol, bad LDL cholesterol, and triglycerides. At the same time, it didn't significantly lower levels of "good" HDL cholesterol.

Some recent studies have shown that soy protein, when eaten along with other cholesterol-lowering foods, can have a big effect. In a study published in the American Journal of Clinical Nutrition in 2005, researchers tested cholesterol-lowering drugs against cholesterol-lowering foods in a group of 34 adults with high cholesterol. People ate 50 grams of soy protein daily along with other cholesterol-lowering foods. The results were striking: the diet lowered cholesterol levels about as well as cholesterol drugs.