New Research Links Omega-3 Status with Cognitive Function
New research from Japan confirms the value of consuming omega-3 fatty acids – docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) to maintain brain function as we age. Not surprising, the benefits of omega’3s to maintain membranes in brains and neural tissues and to support cardiovascular health have been known for years.
To understand the role of omega-3 fatty acids on cognition, Otsuka and colleagues correlated serum DHA and EPA levels with measures of cognitive function in 232 male and 198 apparently healthy, community-dwelling 60-79y old Japanese. The participants were a subset from the National Institute for Longevity – Longitudinal Study of Aging (NILS-LSA) meeting specific criteria. Serum DHA and EPA samples were collected in the morning after fasting for 12h or more at time of enrolment. Cognitive function was assessed by trained health professionals using a Mini-Mental State Examination (MMSE) where higher scores indicate better cognitive function. A 4 point decline in MMSE score and a score of ≤23 (out of maximum = 30) were used as assessment criteria. As tertiles of serum fatty acids increased, the odds ratio (OR) of having a MMSE score decline of at least 4 points decreased significantly. The biggest change occurred between the low and medium tertiles of serum omega-3 levels. The cutoffs were 59.2 µg/mL (~196 µmol/L) for EPA and 139 ug/mL (~422 µmol/L) for DHA, respectively.
To help provide perspective, the most recent nationally representative US data reports that 90% of Americans 60 years and older have EPA and DHA concentrations below 100 µmol/L for EPA (Table 2.33.a.2) and 247 µmol/L DHA (Table 2.37.a.2), respectively. In other words, >90% of Americans over 60y have serum EPA and DHA levels equivalent (or lower) than the reference (control) group reported by Otsuka and associates. Clearly, there is an opportunity to consume more EPA and DHA.
How should this be done? When most Americans consume < 100 mg DHA and EPA daily, we can eat fatty fishy at least twice a week providing 250-500 mg EPA and DHA per serving, as recommended by American Heart Association or World Health Organization. However, this may still not be sufficient to achieve red blood cell EPA and DHA levels of 8%. If you do not wish to eat fish that frequently, Djuric and co-workers demonstrated that dietary supplements containing similar quantities of EPA and DHA per serving can effectively improve omega-3 status.
One can buy EPA and DHA as vegetarian (algae) or fish oils. It is important to read the label for EPA and DHA content per serving. For more information on omega-3s, visit the Council for Responsible Nutrition, Global Organization for EPA and DHA Omega-3 or DHA-EPA Omega-3 Institute.
Otsuka R, Tange C, Nishita Y, Kato Y, Imai T, Ando F, Shimokata H. Serum docosahexaenoic and eicosapentaenoic acid and risk of cognitive decline over 10 years among elderly Japanese. 2013 Eur J Clin Nutr http://dx.doi.org/10.1038/ejcn.2013.264
Ivana D. Djuricic, Sanja D. Mazic, Jelena M. Kotur-Stevuljevic, Vladimir R. Djordjevic, Sladjana S. Sobajic. Long-chain n-3 PUFA dietary recommendations are moderately efficient in optimizing their status in healthy middle-aged subjects with low fish consumption: A cross-over study. 2014 Nutr Res http://dx.doi.org/10.1016/j.nutres.2013.12.008