Kinetics of super( 13)C-DHA before and during fish-oil supplementation in healthy older individuals

• Published in: The American journal of clinical nutrition 2014-07, Vol.100 (1), p.105-105
• Main Authors: Plourde, Melanie, Chouinard-Watkins, Raphaeel, Rioux-Perreault, Christine, tier, Melanie, Dang, Marie Thuy Mai, Allard, Marie-Julie, Tremblay-Mercier, Jennifer, Zhang, Ying, Lawrence, Peter, Vohl, Marie-Claude, Perron, Patrice, Lorrain, Dominique, Brenna, J Thomas, Cunnane, Stephen C
• Format: Article
• Language: English
• ISSN: 0002-9165

Docosahexaenoic acid (DHA) kinetics appear to change with intake, which is an effect that we studied in an older population by using uniformly carbon-13-labeled DHA ( super( 13)C-DHA). We evaluated the influence of a fish-oil supplement over 5 mo on the kinetics of super( 13)C-DHA in older persons. Thirty-four healthy, cognitively normal participants (12 men, 22 women) aged between 52 and 90 y were recruited. Two identical kinetic studies were performed, each with the use of a single oral dose of 40 mg super( 13)C-DHA. The first kinetic study was performed before participants started taking a 5-mo supplementation that provided 1.4 g DHA/d plus 1.8 g eicosapentaenoic acid (EPA)/d (baseline); the second study was performed during the final month of supplementation (supplement). In both kinetic studies, blood and breath samples were collected less than or equal to 8 h and weekly over 4 wk to analyze super( 13)C enrichment. The time x supplement interaction for super( 13)C-DHA in the plasma was not significant, but there were separate time and supplement effects (P < 0.0001). The area under the curve for plasma super( 13)C-DHA was 60% lower while subjects were taking the supplement than at baseline (P < 0.0001). The uniformly carbon-13-labeled EPA concentration was 2.6 times as high 1 d posttracer while patients were taking the supplement as it was at baseline. The mean ( plus or minus SEM) plasma super( 13)C-DHA half-life was 4.5 plus or minus 0.4 d at baseline compared with 3.0 plus or minus 0.2 d while taking the supplement (P < 0.0001). Compared with baseline, the mean whole-body half-life was 61% lower while subjects were taking the supplement. The loss of super( 13)C-DHA through beta -oxidation to carbon dioxide labeled with carbon-13 increased from 0.085% of dose/h at baseline to 0.208% of dose/h while subjects were taking the supplement. In older persons, a supplement of 3.2 g EPA + DHA/d increased beta -oxidation of super( 13)C-DHA and shortened the plasma super( 13)C-DHA half-life. Therefore, when circulating concentrations of EPA and DHA are increased, more DHA is available for beta -oxidation. This trial was registered at clinicaltrials.gov as NCT01577004.