Dietary trans fatty acid.

Trans fatty acids are unsaturated fatty acids that contain at least one double bond in the trans configuration. In the diet they occur at relatively low levels in meat and dairy products as a by-product of fermentation in ruminant animals or in hydrogenated fats as a consequence of the hydrogenation process. In general, dietary hydrogenated fat/trans fatty acids have been reported to increase LDL cholesterol levels relative to oil in the natural state or cis fatty acids. In contrast, dietary hydrogenated fat/trans fatty acids have been reported have to have little effect or decrease HDL cholesterol levels, the later observation restricted to relatively high intakes of trans fatty acids. These two effects result in higher, therefore less favorable, total or LDL cholesterol/HDL cholesterol ratios. Significant increases in Lp(a) levels have been reported after consumption of diets relatively high in trans fatty acids compared with either unsaturated or saturated fatty acids. However, the magnitude of the change is for the most part small and the physiological significance of this observation has yet to be resolved. Data related to the mechanism by which hydrogenated fat/trans fatty acids alter serum lipid levels and other risk factors for cardiovascular disease are in the nascent stages. At this time it would appear prudent that public health recommendations should be aimed at encouraging the moderate consumption of products low in saturated fat or minimally hydrogenated. Trans fatty acids intake should not be stressed at the expense of saturated fat but should augment it.