Dietary Soy, Flaxseed May Prove Beneficial for Obesity, Type II Diabetes

Dietary Soy, Flaxseed May Prove Beneficial for Obesity, Type II Diabetes

NEW ORLEANS--Diets rich in soy protein or flaxseed may be beneficial for many aspects of obesity and diabetes, according to SamBhathena, Ph.D., and researchers from the Phytonutrients Laboratory of the U.S. Department of Agriculture. They presented results of an animal study at Experimental Biology 2002, a meeting of the American Physiological Society (www.the-aps.org).

For 26 weeks, three groups of lean and obese rats were fed one of three diets: 20 percent isolated soy protein, 20 percent flaxseed meal, or a control diet of 20 percent casein. The lean rats were hypertensive (had high blood pressure) while the obese rats showed symptoms of Type II diabetes. At baseline, obese rats had significantly higher levels of plasma glucose, triglycerides, total cholesterol, high-density lipoprotein (HDL, "good") cholesterol and low-density lipoprotein (LDL, "bad") cholesterol.

At the end of the study period, both the soy and flaxseed diets were deemed superior to the control diet. "We found that soy and flax are both effective in reducing obesity and may have some beneficial effects in Type II diabetes," Bhathena said. "Flax appears to have greater beneficial effects than soy."

Specifically, the soy diet was found to decrease total and LDL cholesterol in both lean and obese rats, but did not affect glucose (blood sugar). Comparatively, lean rats on the flaxseed diet exhibited decreased glucose, and the flax diet had greater effects on various study parameters. Flaxseed was seen to decrease total cholesterol and triglycerides in both lean and obese rats, but it also decreased HDL and LDL in the obese rats.

While the reduction in HDL is not necessarily a positive result, Bhathena said that was not the point. "The point is [flaxseed] decreased all factions of cholesterol, not only LDL cholesterol, but it also had an effect on HDL cholesterol in this animal model," he explained. "Many researchers, at least with soy, have observed either no change or only a small increase in HDL cholesterol."