The New Low-Cholesterol Diet: Soy Protein
Versatile soy protein may lower bad fats floating in your bloodstream
By R. Morgan Griffin
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.
However, not all studies agree. A 2005 analysis of various studies led by the U.S. Agency for Healthcare Research and Quality found that soy had a modest effect on cholesterol levels. Researchers found that eating a high amount of soy -- equal to about a pound of tofu a day -- only added up to a 3% reduction in "bad" cholesterol levels.
Nonetheless, the FDA felt that the benefits of soy were clear enough to grant it the status of a "health claim" in 1999. This means that food manufacturers can advertise the heart-healthy benefits on soy products.
Getting Soy Into Your Diet
There are almost endless ways of getting soy into your meal plan. Here's a rundown of some of your options.
Choose the foods that you like. The key is to substitute soy for some meat protein products, especially those that have saturated fat.
How Much Do You Need?
The FDA recommends eating 25 grams of soy protein a day. This amount may lower "bad" cholesterol levels by as much as 10%. Some experts recommend higher levels of up to 50 grams each day.
However, 50 grams is a lot of soy protein. Eating that much every day will take some careful planning and dedication. Start out slowly. Gradually increase the amount of soy in your diet as you figure out the types that you like.
Low-Cholesterol Diet Includes:
SOURCES: Suzanne Farrell, MS, RD, spokeswoman, American Dietetic Association. Ruth Frechman, RD, Los Angeles; spokeswoman, American Dietetic Association. Keecha Harris, DrPH, RD, spokeswoman, American Dietetic Association. FDA web site. American Dietetic Association web site. National Heart, Lung, and Blood Institute web site. American Heart Association web site. Jenkins, D. American Journal of Clinical Nutrition, February 2005; vol 81:pp 380-87. Jenkins, D. Journal of the American Medical Association, July 23-30, 2003; vol 290: pp 502-510.
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Last Editorial Review: 9/30/2005 2:51:57 PM