Fatty acid chain length and degree of unsaturation are inversely associated with serum triglycerides.

Little is known about the association between dietary fatty acids and serum triglycericle concentrations. Plasma fatty acids may reflect dietary intake and can be used to study the relationship between concentrations of individual fatty acids and serum lipids. We examined the cross-sectional relationship of plasma fatty acids with serum nonfasting triglyceride and total cholesterol concentrations. Relative concentrations of individual plasma phospholipid fatty acids were determined by gas liquid chromatography among 4,158 men aged 40-42 yr, who participated in a population study. The pattern of associations between individual fatty acids and cholesterol was different from that between individual fatty acids and triglyceride concentrations. All fatty acids displayed positive associations with total cholesterol concentration except linoleic acid, which was inversely related to cholesterol. In contrast, associations between individual fatty acids and triglyceride concentrations differed in strength and direction depending on both carbon chain length and the degree of unsaturation. Concentrations of very long chain (20 carbon atoms or more) saturated, monounsaturated, and n-3 polyunsaturated fatty acids showed significant inverse associations with triglycerides, whereas shorter fatty acids within these classes were positively associated with triglyceride concentrations. The present data suggest that the associations between concentrations of serum triglycerides and plasma phospholipid fatty acids depend on both fatty acid chain length and the degree of unsaturation.