Background: Fatty acid composition of serum lipids is associated with cardiovascular disease. As attenuated endothelium-dependent vasodilation (EDV) is an early event in atherosclerosis, we investigated the relationships between endothelial vasodilatory function and the proportion of serum fatty acids, reflecting dietary fat quality, in 74 healthy men and women, aged 20-30 years.
Design: Endothelium-dependent vasodilation and endothelium-independent vasodilation (EIDV) was studied in the forearm during local administration of methacholine (2 and 4 micro g min-1) and nitroprusside (5 and 10 micro g min-1). Forearm blood flow was determined with venous occlusion plethysmography. An endothelial function index was calculated as the EDV/EIDV ratio.
Results: The endothelial function index was inversely related to the total proportion of saturated fatty acids (r = -0.41, P < 0.05), in particular lauric and myristic acid (r = -0.37 and r = -0.36, respectively, P < 0.05 for both), and was positively related to the proportion of alpha-linolenic acid (r = 0.45, P < 0.01) in men only. Total serum nonesterified fatty acid (NEFA) concentration was not significantly related to endothelial vasodilatory function. By multiple stepwise regression analysis, including age, blood pressure, body mass index, and serum cholesterol, triglyceride and NEFA as confounders, myristic acid and alpha-linolenic acid were independent predictors of the endothelial function index in men only (r = -0.39 and r = 0.47, respectively, P < 0.01 for both).
Conclusions: We conclude that serum fatty acid composition predicts endothelial vasodilatory dysfunction independently of serum NEFA and cholesterol levels in young, healthy men in their third decade of life, whereas fatty acid composition seems to be less important in women at this age. As a result of the large number of analyses performed, these findings need to be verified by other studies.