title: Serum concentrations of retinol and retinyl esters in adults in response to mixed vitamin A and carotenoid containing meals.
abstract: Previous studies using spectrophotometric methods for vitamin A analysis concluded that fasting prior to blood collection is not necessary for determining vitamin A status of children or young adult subjects. We measured the effect of mixed vitamin A and carotenoid containing meals with less than 3, 50, and 100% of the recommended dietary allowance (RDA) for vitamin A on serum concentrations of retinyl esters, retinol, and carotenoids in elderly and young adults after an overnight fast. Retinyl ester concentrations rose significantly in both age groups with a numerically higher rise over baseline in the elderly subjects: 6.0 +/- 0.9 micrograms/dl for elderly (p less than 0.001), 5.0 +/- 0.5 micrograms/dl for young (p less than 0.001) at 50% RDA; 9.0 +/- 1.3 micrograms/dl for elderly (p less than 0.001) and 6.8 +/- 1.6 micrograms/dl for young (p less than 0.05) at 100% RDA. We conclude that in both young and elderly adults, but especially in the elderly, fasting conditions are necessary for the accurate assessment of vitamin A status if spectrophotometric methods are used for measuring vitamin A.
authors.affiliation: USDA Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111.
authors.forename: H M
authors.initials: HM
authors.lastname: Rasmussen
authors.forename: G E
authors.initials: GE
authors.lastname: Dallal
authors.forename: E
authors.initials: E
authors.lastname: Phelan
authors.forename: R M
authors.initials: RM
authors.lastname: Russell
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002338:Carotenoids / Q000008:administration & dosage* / Q000493:pharmacokinetics; D004952:Esters; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012727:Sex Characteristics; D014801:Vitamin A / Q000008:administration & dosage* / Q000097:blood / Q000493:pharmacokinetics
chemical_list: D004952:Esters; D014801:Vitamin A; D002338:Carotenoids