Facts on Fats Could Prompt Healthier Eating

The 2005 Dietary Guidelines for Americans included—for the first time—recommendations that U.S. consumers keep their intake of trans fatty acids as low as possible. Landmark research conducted by scientists at the Beltsville Human Nutrition Research Center (BHNRC), Beltsville, Md., contributed to that conclusion. The BHNRC is part of the Agricultural Research Service (ARS), the U.S. Department of Agriculture's chief scientific research agency.

In the early ARS study, 58 adult volunteers were fed four different controlled diets, described as moderately high trans fat, high trans fat, high saturated fat, and high “heart healthy” oleic acid.

LDL "bad" cholesterol levels were measured each time the male and female volunteers completed a diet for a 6-week period. The study showed that after the volunteers consumed any of the trans-fat or saturated-fat diets—as opposed to the oleic acid diet—their LDL cholesterol levels were significantly increased.

The scientists also reported that it’s important not to replace dietary trans fats with saturated fats. The dietary guidelines now recommend consuming less than 10 percent of daily calories from saturated fatty acids; that's 22 grams or less for a 2,000-calorie diet. But a 2007 ARS data analysis shows that about 64 percent of adults exceed this recommendation.

The BHNRC researchers studied the levels and sources of saturated fat and unsaturated fats in the American diet. The analysis was based on nationally representative dietary-intake survey data from What We Eat in America/NHANES 2003-2004. The research was led by nutritionist Alanna J. Moshfegh, who heads the BHNRC Food Surveys Research Group.

Read more about this research in the March 2008 issue of Agricultural Research magazine.