Administration of low doses of fish oil derived N-3 fatty acids to elderly subjects

Abstract

Objectives: To assess the incorporation of n-3 polyunsaturated fatty acids (PUFA) in plasma and erythrocyte lipids of elderly subjects after ingestion of very low doses of fish oil. The effects on α-tocopherol and retinol concentrations were also studied. Setting: Municipal nursing home in Barcelona, Spain. Subjects: Forty-five elderly subjects aged 60–92 y. Design and intervention: Subjects received a non-commercialized milk formula containing 1% fish oil for 15 months, which provided 0.40 g/d of n-3 PUFA. Fatty acid profiles and antioxidant concentrations were measured before and after the intervention period. Results: Fish oil ingestion was associated with significant increases in total n-3 PUFA in plasma and erythrocytes by 32% and 18%, respectively. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acid concentrations were higher after the ingestion period both in plasma and erythrocytes (P<0.05), whereas linoleic and arachidonic acids remained unchanged. The n-6/n-3 ratio decreased by 21% in plasma and by 16% in erythrocytes (P<0.05). Moreover, younger subjects showed a greater incorporation of EPA and DHA than older subjects. Plasma α-tocopherol and retinol concentrations did not vary significantly, whereas erythrocyte α-tocopherol was significantly higher after the intervention period. Conclusion: This study shows that low doses of n-3 PUFA supplemented with adequate amounts of α-tocopherol can be incorporated into blood lipids in elderly subjects without lowering their antioxidant concentrations. Sponsorship: This study was supported by a research grant from the Spanish CDTI.