Metabolism of uniformly labeled 13C-eicosapentaenoic acid and 13C-arachidonic acid in young and old men

Abstract

Background: Plasma eicosapentaenoic acid (EPA) and arachidonic acid (AA) concentrations increase with age.Objective: The aim of this study was to evaluate EPA and AA metabolism in young and old men by using uniformly labeled carbon-13 (13C) fatty acids.Design: Six young (∼25 y old) and 6 old (∼75 y old) healthy men were recruited. Each participant consumed a single oral dose of 35 mg 13C-EPA and its metabolism was followed in the course of 14 d in the plasma and 28 d in the breath. After the washout period of ≥28 d, the same participants consumed a single oral dose of 50 mg 13C-AA and its metabolism was followed for 28 d in plasma and breath.Results: There was a time × age interaction for 13C-EPA (Ptime × age = 0.008), and the shape of the postprandial curves was different between young and old men. The 13C-EPA plasma half-life was ∼2 d for both young and old men (P = 0.485). The percentage dose recovered of 13C-EPA per hour as 13CO2 and the cumulative β-oxidation of 13C-EPA did not differ between young and old men. At 7 d, however, old men had a >2.2-fold higher plasma 13C-DHA concentration synthesized from 13C-EPA compared with young men (Page = 0.03). 13C-AA metabolism was not different between young and old men. The 13C-AA plasma half-life was ∼4.4 d in both young and old participants (P = 0.589).Conclusions: The metabolism of 13C-AA was not modified by age, whereas 13C-EPA metabolism was slightly but significantly different in old compared with young men. The higher plasma 13C-DHA seen in old men may be a result of slower plasma DHA clearance with age. This trial was registered at clinicaltrials.gov as NCT02957188.

Keywords: aging; arachidonic acid; docosahexaenoic acid; eicosapentaenoic acid; metabolism.

© 2017 American Society for Nutrition.