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Providing perspectives on recent research into vitamins and nutritionals


Omega-3 Index, Inflammation and Cardiovascular Health

By Michael McBurney

Inflammation is observed in individuals,  especially obese persons, even without evidence of cardiovascular disease, a high incidence of metabolic syndrome and risk of diabetes. Inflammation may lead to atherosclerosis of vessels to increase risk of stroke and heart attack. Although prescription medicines called statins appear to reduce arterial inflammation, the American College of Cardiology and American Heart Association guidelines to expand statin therapies to older individuals without cardiovascular disease discounts the role of nutrition in maintaining health.

Prostaglandin thromboxanes stimulate platelet aggregation and increase the risk of thrombotic blockages in blood flow. Omega-3 fatty acids can displace ω-6 long-chain polyunsaturated fatty acids (LCPUFA) to suppress the synthesis of pro-inflammatory thromboxanes by platelets. Aspirin inhibits platelet-cyclooxygenase-1 (COX-1) which also generates thromboxane A2 (TxA2).   DeFilippis and colleagues report that baseline omega-3 fatty acids do not affect TxA2 generation in patients with CVD taking aspirin. Their conclusion most likely reflects a lack of subjects (n = 54) because the correlation coefficients approach significance for EPA (r = 0.098), DHA (r=0.054), omega-3 (r=0.091) and EPA+DHA (r=0.072).

Alternatively, it may reflect suboptimal omega-3 fatty acid concentrations to affect inflammatory markers. The average omega-3 index [%EPA + %DHA]  was only 3.8%. As a comparison, a randomized, controlled trial (RCT) involving healthy individuals with moderate triglyceridemia reported a baseline omega-3 index of 4.5% with % RBC EPA and DHA concentrations of 0.5% and 4.0%, respectively. RBC fatty acid levels increased over 8 weeks with 0.85 and 3.4g daily of EPA+DHA in a dose-dependent manner. After 8 weeks of 3.4g EPA+DHA per day, the omega-3 index was 8.8% with 2.3% EPA and 6.5% DHA. An omega-3 index below 4% is unhealthy and >8% is optimal.

Burns-Whitmore and colleagues demonstrate that ingesting a direct source of DHA is more effective approach to increase RBC fatty acid levels than the ω-3 precursor α-linolenic acid.

Bottom line, we are what we eat. When choosing products with ω-3 long-chain polyunsaturated fatty acids to increase your omega-3 index, choose the product with the most EPA and DHA content per serving.

Main Citations

DeFilippis AP, Rai SN, Cambon A, Miles RJ, Jaffe AS, Moser AB, Jones Ro, Bolli R, Schulman SP. Fatty acids and TxA2 generation, in the absence of platelet-COX-1 activity. 2014 Nutr Metab CVD doi: 10.1016/j.numecd.2013.08.012

Burns-Whitmore B, Haddad E, Sabate J, Rajaram S. Effects of supplementing n-3 fatty acid enriched eggs and walnuts on cardiovascular disease risk markers in healthy free-living lacto-ovo-vegetarians: a randomized, crossover, free-living intervention study. 2014 Nutr J doi: 10.1186/1475-2891-13-29

Other Citations

Tona F, Serra R, Di Ascenzo L, Osto E, Scarda A, Fabris R, Montisi R, Famoso G, Tellatin S, Foletto M, Giovagnoni A, Illiceto S, Vettor R. Systemic inflammation is related to coronary microvascular dysfunction in obese individuals without obstructive coronary disease. 2014 Nutr Metab CVD doi:10.1016/j.numecd.2013.09.021

Pencina MJ, Navar-Boggan AM, D’Agostino Sr RB, Williams K, Neely B, Sniderman AD, Petersen ED. Application of new cholesterol guidelines to a population-based sample. 2014 NEJM doi:10.1056/NEJM011315665

Skulas-Ray AC, Kris-Etherton PM, Harris WS, Vanden Heuvel JP, Wagner PR, West SG. Dose-response effects of omega-3 fatty acids on triglycerides, inflammation, and endothelial function in healthy persons with moderate hypertriglyceridemia. 2011 Am J Clin Nutr doi: 10.3945/ajcn.110.003871

Harris WS, von Shacky C. The omega-3 index: a new risk factor for death from coronary heart disease. 2004 Prev Med doi: 10.1016/j.ypmed.2004.02.030