Blood EPA Levels and Mortality in Elderly
Lindberg et al., Am. J. Clin. Nutr. 88: 722-729, 2008
Department of Medical Biochemistry, St Olavs Hospital, Trondheim University Hospital, Trondheim, Norway
The primary objective of this investigation as reported from Norway was to evaluate the potential relationship between the long-chain omega-3 status as measured by the blood levels of EPA (eicosapentaenoic acid) in acutely sick elderly patients (hospitalized) and their risk of mortality evaluated after three years of follow-up. The total population studied included 254 frail, elderly patients with a mean age of 82 years. Since blood levels of EPA reflect marine-derived omega-3 fatty acid intakes, blood plasma samples were taken and the levels of EPA (as a percent of total fatty acids in plasma phospholipid) were determined. The mean level of EPA in the total population was 2.02% of total fatty acids and 1.01% for those in the low-EPA group as compared to 2.35% for those in the high-EPA group. After three years, 73% of those in the low-EPA group had died as compared to a 40% mortality in the high-EPA group. The median survival time was 1.5 years in the low-EPA group and 2.4 years in the high-EPA group. Cardiac disease was the major cause of death in both groups with other major causes being infection, cancer, and stroke. The authors determined by statistical modeling that the risk of death was 47% lower in those subjects with EPA levels surpassing 1.25% of total fatty acids and was very similar to those having average EPA levels up to 2.25% of total fatty acids (the higher quartile of the population).
These findings on the apparent inverse relationship between higher levels of EPA in the circulation (and presumably in the diet from marine sources) are of considerable interest with respect to the omega-3 fatty acid contents provided in the meals for those frail, elderly who are institutionalized and/or hospitalized. From the large body of published literature on the levels of EPA as a percent of total fatty acids in plasma (serum) phospholipid in both young and elderly adults in North America, the majority do not have levels of EPA which surpass 1.25% of total fatty acids. This is the situation for many countries globally with exceptions such as in Japan with high seafood intakes and other geographical locations.