The Omega-3 Index is higher in people from a coastal town versus 5 inland US cities: An observational study

Abstract

Higher omega-3 fatty acid blood levels, as assessed by the Omega-3 Index (O3I, erythrocyte eicosapentaenoic [EPA] + docosahexaenoic [DHA] percentage), have been linked with lower risk for cardiovascular disease and total mortality. Because seafood is an excellent source of EPA and DHA, we reasoned that people living on the coast with direct access to fresh seafood might have higher O3I levels than people living inland. Using O3I data originally collected for other purposes and an observational design, we compared the mean O3I from people in Newport, RI, with that of people living from 5 inland US cities (Indianapolis, IN; Charleston, WV; Lexington, KY; Oklahoma City, OK; and Memphis, TN). The Newport samples were collected at free, industry-sponsored health fairs, whereas the inland city samples were collected at free public health screenings sponsored by the Seafood Nutrition Partnership in 2014 through 2015. The mean (standard deviation) O3I in the Newport sample (n = 226) was 5.13% (1.34%) and the mean of the 5 cities (n = 1109) was 4.48% (1.08%) (P < .001). An O3I of ≥8% (considered optimal) was found in 3% of the Newport sample and in 1% of the pooled inland cities (P < .05). An O3I of ≤4% (considered low) was found in 22% of the Newport sample and in 41% of the pooled inland cities (P < .001). These data support our hypothesis, but because only 3% of those in the Newport sample had an O3I >8%, even greater seafood intake (or the use of fortified foods or dietary supplements) is needed to attain optimal omega-3 status.