U.S. Department of Agriculture scientist Dr. Timothy Sanders and North Carolina State University graduate student Amanda Stephens, both in Raleigh, N.C., said the research indicates separate and significant health benefits in the non-oil portion of the peanut.

The study compared the effects of four diets in hamsters that contained similar amounts of fat, carbohydrates and protein. In three of the diets, peanuts, peanut oil, or fat-free peanut flour were substituted for equivalent caloric amounts of food. The fourth diet served as a control.

Compared to the control group, all three of the peanut diets significantly lowered total cholesterol and low-density lipoprotein, or LDL, the "bad" cholesterol. In addition, the high-density lipoproteins, or HDL, the "good" cholesterol remained steady.

"We now have shown that there are components beyond the healthy fat in peanuts that are having strong health benefits," Sanders said in a statement. "The protein and other functional components in peanuts, which are in the peanut flour, also improve heart disease risk factors."

The findings were presented at the annual Institute of Food Technologists meeting in New Orleans.