Study Shows Soy Protein Lowers Men's Cholesterol By
Soy protein can be an important ally in lowering cholesterol, according to
new findings from a study conducted at the
Children's Nutrition Research Center
in Houston, Texas. This research, published in the October issue of American Journal of Clinical
Nutrition, may also explain why previous studies have produced
conflicting evidence concerning the merits of soy protein.
The study results suggested soy protein can enhance the effects of a diet
designed to lower cholesterol. This holds true for men whose levels are in the
safe cholesterol range and those above it. The Children's Nutrition Research
Center is jointly managed by the Agricultural
Research Service, the chief research agency of the
U.S. Department of Agriculture, and
Baylor College of Medicine.
The study involved 26 men, 20 to 50 years of age, half of whom had high
cholesterol. All the men went on the
Cholesterol Education Program's Step I diet to lower their cholesterolbut
with a special twist. Half of the subjects were getting their protein from soy;
half from meat.
Then, after a 10-to-15 week "washout" period, the two groups
swapped diets; those receiving their protein from soy switched to meat, and vice
While both groups of men experienced improved blood cholesterol on both
diets, those receiving soy improved more than those receiving meat protein,
regardless of age or weight.
Low density lipoprotein-cholesterol (LDL-C) is associated with increased
heart-disease risk. Men with cholesterol problems who went on the meat-protein
diet dropped their LDL- cholesterol 8 percent, but their LDL-cholesterol dropped
13 percent on the soy-protein version. The percentage for men with "safe"
LDL-cholesterol levels was smaller5 percent for meat and 11 percent for
Researchers suggested that previous studies finding little benefit from soy
may not have included a "washout period" or adequately monitored
subjects' diets. The men in this study ate only pre-packaged meals prepared at
William W. Wong,
USDA-ARS, Children's Nutrition Research Center at Baylor College of Medicine,
Houston, Tex., (713) 798-7168; fax: (713) 798-7119,