Hopefully your Omega-3 Index Exceeds 8%? Find Out Why
The fatty acids found in the membranes of erythrocytes, also known as red blood cells (RBC), reflect the type of fats (animal, plant, seafood) being consumed and their fatty acid composition (saturated, monosaturated, polyunsaturated). The omega-3 index, the percentage of total fatty acids which are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in RBC membranes may be a biomarker of cardiovascular risk, especially cardiac death.
An omega-3 index about 8% is cardioprotective whereas the risk of coronary heart disease death increases when < 4%. Using samples from the MONA LISA-NUT survey, Wagner and colleagues report a mean omega-3 index of 6.0% among 503 French subjects (35-64 y). The French are known for their healthy Mediterranean diet. However, average values gloss over important sources of heterogeneity within a population. As an example, the omega-3 index was higher in 55-64y than 35-44y adults. The index was lower in people living in eastern France (< 6%) than western France (>6.4%). People consuming seafood ≤ 1 per month had the lowest omega-3 index (4.8%). Still the worst subgroup in France had a higher omega-3 index than the average American (4.3%), who if not using fish oil supplements, has an average index of 3.4%.
The consumption of EPA and DHA is consistently associated with reductions in cardiac death. With total EPA and DHA intakes often below 100 mg daily, it is important to increase EPA+DHA intake from seafood, fortified foods, or with dietary supplements. The recommendation is to achieve an omega-3 index ≥ 8%. Supplementation with 0.94 g DHA daily, in this case an microalgal oil, for 8 wk raised the omega-3 index above 8% in most subjects with low initial basal RBC EPA and DHA concentrations (omega-3 index = 4.8%).
Although bioavailability claims are being made with respect to form (phospholipid, di- and tri-glycerides, and non-esterified fatty acids), the comparisons are questionable and clinical evidence doesn’t exist to show differences in long-term benefits.
Bottom line: If you aren’t a regular consumer of seafood, choose a supplement based on its EPA and DHA content. The amount of EPA and DHA per serving can be found on the Supplement Facts Panel. Most importantly, be a regular user.
Wagner A, Simon C, Morio B, Dallongeville J, Ruidavets JB, Haas B, Laillet B, Cottel D, Ferrieres J, Arveiler D. Omega-3 index levels and associated factors in a middle-aged French population: the MONO LISA-NUT Study. 2014 Eur J Clin Nutr doi: 10.1038/ejcn.2014.219
Harris WS. Omega-3 fatty acids and cardiovascular disease: A case for omega-3 index as a new risk factor. 2007 Pharmacol Res doi: 10.1016/j.phrs.2007.01.013
Harris WS, von Shcacky 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
Block RC, Harris WS, Pottala JV. Clinical investigation: Determinants of blood cell omega-3 fatty acid content. 2008 Open Biomarkers J doi: 10.2174/1875318300801010001
Kuratko CN, Nolan CC, Salem Jr N. Long-chain omega-3 fatty acids and cardiovascular health. 2014 Nutrfoods doi: 10.1007/s13749-014-0020-7
Nichols PD, Kitessa SM, Abeywardena M. Commentary on a trial comparing krill oil versus fish oil. 2014 Lipids Health Disease doi: 10.1186/1476-511X-13-2
Salem N, Kuratko CN. A reexamination of krill oil bioavailability studies. 2014 Lipids Health Disease doi: 10.1186/1476-511x-13-137
Geppert J, Kraft V, Demmelmair H, Koletzko B. Docosahexaenoic acid supplementation in vegetarians effectively increases omega-3 index: A randomized trial. 2005 Lipids doi: 10.1007/s11745-00501442-9