Omega-3 Index, Inflammation and Cardiovascular Health
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.
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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
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