Will Soy Protein Be Next Fad?

Is there tofu in your future?

The spongy bland stuff, and other food made from soy protein, might be the next dietary fad. A new study suggests they lower cholesterol.

Most talk about the dos and don’ts of a heart-healthy diet focuses on fats, which can affect cholesterol in the bloodstream.

With the latest work, attention is turning to protein. The report concludes that people with seriously high cholesterol can bring it down if they replace some of the animal protein in their diets with soy protein.

The researchers theorized that a vegetable form of estrogen known to be present in soy protein directly lowers cholesterol, though exactly how isn’t clear. Human estrogen was previously known to bring cholesterol down.

“Soy protein is a very valuable asset to the diet,” said Dr. James W. Anderson. “It’s grossly underused by the American public.”

Soy is widely available as tofu, in drinks, in meat substitutes that have the consistency of hamburger and as flour that can be used in baking.

Anderson published his analysis in today’s issue of the New England Journal of Medicine. He said he received $5,000 from Protein Technologies International, which makes soy protein, to help pay for the work.

He and colleagues from the Veterans Affairs Medical Center in Lexington, Ky., combined the results of 38 comparison studies of soy protein involving 730 people. Individually, the studies were too small to be conclusive. But put together, the benefits emerge clearly, the researchers say.

In all of these studies, scientists partially substituted soy protein for some of the animal protein in the people’s diets and looked at the effects on their cholesterol. The volunteers consumed the same kinds and amounts of fat and cholesterol, regardless of which type of protein they were getting.

On average, they ate 47 grams of soy protein a day in place of animal protein, which usually comes from dairy products, meat and poultry.

Overall, cholesterol levels fell 23 milligrams per deciliter, or 9 percent, while eating soy protein. However, the effects were significant only for those who already had moderately elevated cholesterol of 259 or above. The biggest benefits were in people with cholesterol over 335.

Only LDL, the so-called bad cholesterol, fell during the soy diets. Levels of HDL, the form of cholesterol that protects against heart disease, did not change.

Anderson said he believes 20 milligrams of soy protein a day, substituted for animal protein, could be enough to help those who need to lower their cholesterol.

Eight ounces of soy milk contain 4 to 10 grams of soy protein; four ounces of tofu have 8 to 13 grams; one ounce of soy flour has 10 to 13 grams.