Higher plasma n-3 fatty acid status in the moderately healthy elderly in southern Québec: Higher fish intake or aging-related change in n-3 fatty acid metabolism?

The elderly reportedly have a significantly higher % of eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in plasma and red cell lipids. However, these observations are from a few small studies and the health status of the elderly in these studies is for the most part unclear. Since the elderly are susceptible to cardiovascular and neurological illnesses that seem to be related in part to lower intake of n-3 fatty acids it seems paradoxical that their blood levels of EPA and DHA would be higher than in young adults. We report here plasma fatty acid profiles and their response to supplementation with two types of fish oils from several of our recent studies in the moderately healthy elderly. We define the moderately healthy elderly as those who were in good physical condition, had no cognitive decline and, if present, in whom hypothyroidism, hyperlipidemia and/or hypertension were well-controlled. As shown previously, we confirm the higher % EPA and % total n-3 fatty acids (but not DHA) in fasting plasma and extend these findings to include higher plasma concentrations (mg/L) of n-3 fatty acids as well. The EPA-predominant supplement raised DHA only in the young, whereas the DHA-predominant supplement raised EPA more in the young than in the elderly. The moderately healthy elderly clearly have higher plasma n-3 fatty acids but whether this reflects differences in intake versus aging-related changes in n-3 fatty acid metabolism remains to be elucidated. n-3 Fatty acids from fish are now generally recognized as beneficial for optimal function of the cardiovascular system in adults, whether consumed as fish or as fish oil supplements. Long term fish intake is also associated with a lower risk of cognitive decline and Alzheimer’s disease during aging [1,2], but it is not yet clear that n-3 fatty acid or fish oil supplements can replace long term fish intake for this purpose [3]. Because of the increasing risk of deteriorating health of the cardiovascular system and brain with age, we and others have sought to establish whether healthy aging is associated with changes in plasma n-3 fatty acid content or response to n-3 fatty acid supplementation that would leave the elderly with poorer n3 fatty acid status that predisposes them to these degenerative