Plasma incorporation, apparent retroconversion and β-oxidation of 13C-docosahexaenoic acid in the elderly

Abstract

BackgroundHigher fish or higher docosahexaenoic acid (DHA) intake normally correlates positively with higher plasma DHA level, but recent evidence suggests that the positive relationship between intake and plasma levels of DHA is less clear in the elderly.MethodsWe compared the metabolism of 13C-DHA in six healthy elderly (mean - 77 y old) and six young adults (mean - 27 y old). All participants were given a single oral dose of 50 mg of uniformly labelled 13C-DHA. Tracer incorporation into fatty acids of plasma triglycerides, free fatty acids, cholesteryl esters and phospholipids, as well as apparent retroconversion and β-oxidation of 13C-DHA were evaluated 4 h, 24 h, 7d and 28d later.ResultsPlasma incorporation and β-oxidation of 13C-DHA reached a maximum within 4 h in both groups, but 13C-DHA was transiently higher in all plasma lipids of the elderly 4 h to 28d later. At 4 h post-dose, 13C-DHA β-oxidation was 1.9 times higher in the elderly, but over 7d, cumulative β-oxidation of 13C-DHA was not different in the two groups (35% in the elderly and 38% in the young). Apparent retroconversion of 13C-DHA was well below 10% of 13C-DHA recovered in plasma at all time points, and was 2.1 times higher in the elderly 24 h and 7d after tracer intake.ConclusionsWe conclude that 13C-DHA metabolism changes significantly during healthy aging. Since DHA is a potentially important molecule in neuro-protection, these changes may be relevant to the higher vulnerability of the elderly to cognitive decline.

RETRACTED ARTICLE: Aging decreases rate of docosahexaenoic acid synthesis-secretion from circulating unesterified α-linolenic acid by rat liver

“…6a, b). The results are consistent with a human study that showed that orally administered 13 C-DHA was retained longer in plasma esterified and unesterified fatty acid pools of elderly than young subjects (Plourde et al 2011).…”

“…The resulting unesterified DHA can enter the brain to replace DHA lost due to metabolism (DeMar et al 2004). In one human study, incorporation of orally-administered 13 C-DHA into plasma esterified and unesterified fatty acid pools increased with age (Plourde et al 2011), suggesting age-related changes in whole-body including liver DHA metabolism and changes in the liver's capacity to maintain plasma esterified and unesterified DHA concentrations.…”

Relationship between diet and plasma long-chain n-3 PUFAs in older people: impact of apolipoprotein E genotype

“…Short-term administration of an EPA+DHA supplement is accompanied by a higher increase in plasma DHA in healthy older adults than in younger adults ( 18 ). The elderly also metabolize an oral dose of carbon-13-labeled DHA differently than young adults ( 19 ). In neither of these studies were participants separated according to APOE4 genotype.…”

“…In addition, older individuals have higher plasma EPA and DHA concentrations in response to supplementation with long-chain n-3 PUFAs than younger adults ( 18 ) or after an oral dose of carbon-13 DHA ( 19 ), suggesting signifi cant differences in n-3 PUFA metabolism in older age.…”

The phospholipid composition of the human entorhinal cortex remains relatively stable over 80 years of adult aging

“…More recently it has been suggested that dietary consumption of seafood as a source of DHA may be more important for prevention of AD than supplementation, with APOEε4 carriers who consumed seafood at least once per week showing a lower burden of neuritic plaques and neurofibrillary tangles at death (Morris et al 2016). However, the discrepancies between intervention studies could also be the product of an alteration to DHA metabolism even in normal, healthy adults with advanced age (Astarita et al 2010;Plourde et al 2011). Needless to say, much work remains to be done in this area to determine the best way of maintaining DHA levels within the brain over the lifespan.…”