SERUM CONCENTRATIONS OF RETINOL AND RETINYL ESTERS IN ADULTS IN RESPONSE TO MIXED VITAMIN-A AND CAROTENOID CONTAINING MEALS

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 concentration 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-mu-g/dl for elderly (p < 0.001), 5.0 +/- 0.5-mu-g/dl for young (p < 0.001) at 50% RDA; 9.0 +/- 1.3-mu-g/dl for elderly (p < 0.001) and 6.8 +/- 1.6-mu-g/dl for young (p < 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.