Study Probes Potential Health Benefits of DHA

By Marcia Wood
September 2, 1998

A natural compound in fish and meats improved two cardiovascular health indicators in six volunteers for an Agricultural Research Service nutrition study. ARS scientists found that these volunteers, who ate foods enriched with an omega-3 fatty acid called "DHA," showed an increase in HDL-cholesterol--the kind known to protect against heart disease. And, blood fats known as triglycerides decreased by about 26 percent.

The volunteers on the high-DHA regimen showed an increase of about 69 percent in apoprotein-E, a compound that carries cholesterol to the liver for breakdown and excretion. An apo-E increase had not been reported in other DHA studies with humans, according to Gary J. Nelson of the ARS Western Human Nutrition Research Center, San Francisco, Calif. Nelson led the study, the longest DHA experiment yet reported with in-residence volunteers. Ten healthy, non-smoking men age 20 to 39 lived at the research center for the four-month investigation.

DHA is short for docosahexaenoic acid. Scientists added about a teaspoon of DHA- rich oil to salad dressings or bean, salsa or guacamole dips served to six volunteers, substituting safflower oil in the servings for the four other men. Nelson designed the study to distinguish the effects of DHA from those of another omega-3 fatty acid, EPA. Both occur in fish oils thought to have cardiovascular benefits. An article in the September 1998 issue of the agency's monthly magazine, Agricultural Research, tells more. View it on the World Wide Web at:

/is/AR/archive/sep98/dha0998.htm

ARS is the principal research agency of the U.S. Department of Agriculture.

Scientific contact: Gary J. Nelson, USDA-ARS Western Human Nutrition Research Center, P.O. Box 29997, Presidio of San Francisco, CA 94129, phone (415) 556-0899, fax (415) 556-1432, e-mail gnelson@whnrc.usda.gov.