Position paper on trans fatty acids. ASCN/AIN Task Force on Trans Fatty Acids. American Society for Clinical Nutrition and American Institute of Nutrition.

This report addresses the current controversy about possible health hazards of dietary trans fatty acid isomers, which are created during hydrogenation of unsaturated fats to change their textural properties and melting points. Estimates of intakes are approximations based on limited data and problematic analytic techniques. Major contributors in the diet are fried and baked foods and margarine, in which partially hydrogenated vegetable oils may replace fat sources richer in saturated fatty acids and cholesterol. Consumption of trans fatty acids in the United States has been relatively constant, and new food technologies are yielding decreases in the trans fatty acid content of commercially prepared foods. When intake of trans fatty acids (as hydrogenated fat) is compared with that of saturated fat, total and low-density-lipoprotein (LDL)-cholesterol concentrations in blood are lower, but both trans fats and saturated fats increase total and LDL concentrations when compared with cis fatty acids or native unhydrogenated fat. Epidemiologic data are conflicting with respect to cardiovascular disease outcomes. We cannot conclude that the intake of trans fatty acids is a risk factor for coronary heart disease nor can we expect that substituting trans- for cis-containing fats will reduce the risk of coronary heart disease. Few rigorous studies have dealt with biomedical effects of trans fatty acids and possible mechanisms relevant to human health and diseases. The nutrition labeling issue is unresolved. The options, recommendations, and research suggestions in this report should outline for nutrition scientists the database needed before any new dietary recommendations or changes in nutrition policy concerning trans fatty acids can be made. The debate about trans fatty acids should not detract from dietary recommendations to limit the intake of saturated fat and total fat.