Omega-3 fatty acid intake associated with cardiovascular disease prevention

Harvard researchers report that increased consumption of omega-3 fatty acids in the diet is associated with lower levels of inflammation and endothelial activation. Dysfunction of the endothelium, which is the inner lining of the blood vessel wall, is an early event in the development of atherosclerosis. Omega-3 fatty acids have been found to provide a protective benefit against cardiovascular disease, and in addition to reducing triglycerides, platelet aggregation and cardiac arrhythmias, appear to play yet other roles in heart disease prevention. The July 2004 Journal of Nutrition (http://www.nutrition.org/) published these findings.

Food frequency questionnaires completed in 1986 and 1990 by 727 participants in the Nurses’ Health study were evaluated for levels of the omega-3 fatty acids alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA). Blood samples collected between 1989 and 1990 provided measurements of the inflammatory and endothelial activation markers C-reactive protein, interleukin-6, E-selectin, soluble tumor necrosis factor receptor 2 (sTNFR-2) and soluble cell adhesion molecules (sICAM-1 and sVCAM-1).

Alpha-linolenic acid consumption was found to be inversely associated with plasma C-reactive protein, interleukin-6 and E-selectin levels, while EPA and DHA intake was inversely related to soluble cell adhesion molecule levels. Total fatty acids were inversely related to all of these levels.

The researchers suggest that a possible pathway used by omega-3 fatty acids to inhibit inflammation and endothelial activation is by decreasing the body’s production of hydrogen peroxide, which is involved in the inflammatory process. They believe that their findings may provide a partial explanation for the benefit of omega-3 fatty acids in cardiovascular disease prevention.

Abstract

We evaluated the hypothesis that intake of omega-3 fatty acids is inversely associated with biomarkers of inflammation and endothelial activation. We conducted a cross-sectional study of 727 women from the Nurses’ Health Study I cohort, aged 43–69 years, apparently healthy at time of a blood draw in 1990. Dietary intake was assessed by a validated FFQ in 1986 and 1990.

C-reactive protein (CRP) levels were 29% lower among those in the highest quintile of total (n-3) fatty acids, compared with the lowest quintile; interleukin-6 (IL-6) levels were 23% lower, E-selectin levels 10% lower, soluble intracellular adhesion molecule (sICAM-1) levels 7% lower, and soluble vascular adhesion molecule (sVCAM-1) levels 8% lower. The intake of -linolenic acid was inversely related to plasma concentrations of CRP (ß = –0.55, P = 0.02), Il-6 (ß = –0.36, P = 0.01), and E-selectin (ß = –0.24, P = 0.008) after controlling for age, BMI, physical activity, smoking status, alcohol consumption, and intake of linoleic acid (n-6) and saturated fat. Long-chain (n-3) fatty acids (eicosapentaenoic and docosahexaenoic) were inversely related to sICAM-1 (ß = –0.11, P = 0.03) and sVCAM-1 (ß = –0.17, P = 0.003). Total (n-3) fatty acids had an inverse relation with CRP (ß = –0.44, P = 0.007), IL-6 (ß = –0.26, P = 0.009), E-selectin (ß = –0.17, P = 0.004), sICAM-1 (ß = –0.07, P = 0.02), and sVCAM-1 (ß = –0.10, P = 0.004). These associations were not modified by intake of vitamin E, dietary fiber, trans fatty acids, or by the use of postmenopausal hormone therapy.

In conclusion, this study suggests that dietary (n-3) fatty acids are associated with levels of these biomarkers reflecting lower levels of inflammation and endothelial activation, which might explain in part the effect of these fatty acids in preventing cardiovascular disease.

Reference

Consumption of (n-3) Fatty Acids Is Related to Plasma Biomarkers of Inflammation...
Lopez-Garcia et al. J. Nutr. 134:1806-1811, July 2004.

Key concepts: omega-3 fatty acids, cardiovascular disease, inflammation, endothelial activation