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Providing perspectives on recent research into vitamins and nutritionals


Whoa…Researchers find Low Omega-3 Index is Common

By Michael McBurney

Low intakes of dietary omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), found in fish, fish oils and algal oils are reflected in low blood concentratiosn. The omega-3 index is a measure of DHA+EPA concentrations in blood. Harris proposed that an omega-3 index of <4% was a high risk indicator for coronary heart disease.

Using the most recently published national data on blood omega-3 fatty acid concentrations, a new study finds ~96% of American adults have an omega-3 index below levels associated with cardiovascular protection (~4%). Hispanic adults are more likely to not meet this criterion of adequacy for cardiovascular health. Earlier this year, Langlois and Ratnayake reported <3% of adults living in Canada had omega-3 index levels associated with low risk for coronary heart disease. North Americans are not unique; most Saudi adults have an omega-3 index <3.5%.

It is important to maintain a healthy omega-3 index. When evaluating conclusions/recommendation from analyses of  randomized, controlled intervention trial data, it is important to consider the following:

1) Is the omega-3 index of the participants known? It should be. Why? The benefits of increasing omega-3 intake depend upon baseline omega-3 index. The potential impact on coronary heart disease incidence obtained by increasing dietary will take decreases as the baseline omega-3 index of the study population increases.

2) Is the amount of omega-3 being supplied adequate?  Studies need to provide adequate amounts of omega-3 fatty acids for sufficient periods to change the omega-3 index. The benefits of supplementation are dose and duration dependent.

The low omega-3 index in American adults is not unexpected. Median daily DHA and EPA intake from food alone is only 18 and 50mg daily, respectively. When supplements are included, median total DHA and EPA intake only increases to 41±4 mg and 72±4 mg, respectively.

The American Heart Association recommends eating fish (particularly fatty fish) at least two times (two servings) per week (except for children and pregnant women who are at risk because of mercury exposure). For more information on omega-3 fatty acids, including supplements, go to the Global Organization for EPA and DHA Omega-3s website.

Main Citation

Murphy RA, Yu EA, Ciappio ED, Mehta S, McBurney MI. Suboptimal plasma long chain n-3 concentrations are common among adults in the United States, NHANES 2003-2004. 2015 Nutrients doi: 10.3390/nu7125534

Other Citations

Harris WS. The omega-3 index as a risk factor for coronary heart disease. 2008 Am J Clin Nutr 87 (6): 19975-20025

Langlois K, Ratnayake WM. Omega-3 index of Canadian adults. 2015 Health Rep 26(11) 82-003-x

Bassam T, Superko HR, Caulfield M. Cardiovascular disease risk attributed to blood fish oil (omega-3 fatty acid) levels differ significantly in Saudi men and women. 2015 J Saudi Heart Asso doi: 10.1016/j.jsha.2015.05.202

Papanikolaou Y,  Brooks J, Reider C, Fulgoni VL. US adults are not meeting recommended levels for fish and omega-3 fatty acid intake: results from an analysis using observational data from NHANES 2003-2008. 2014 Nutr J doi: 10.1186/1475-2891-13-31

Miller PE, Van Eslwyk M, Alexander DD. Long-chain omega-3 fatty acids eicosapentaenoic acid and docosahexaenoic acid and blood pressure: A meta-analysis of randomized controlled trials. 2014 Am J Hypertens doi: 10.1093/ajh/hpu024

Barringer TA. Do omega-3 fatty acids have a role in prevention of cardiovascular disease? 2012 Front Physiol doi: 10.2289/fphys.2012.00395