Dietary vitamin A intakes of Filipino elders with adequate or low liver vitamin A concentrations as assessed by the deuterated-retinol-dilution method: Implications for dietary requirements

Abstract

Background: The vitamin A requirements of elderly humans have not been studied. Objective: In a cross-sectional study of 60-88-y-old men (n = 31) and women (n = 31) in rural Philippines, we assessed the dietary intakes of elders with adequate (≥ 0.07 μmol/g) or low (< 0.07 μmol/g) liver vitamin A concentrations to estimate vitamin A requirements for this age group. Design: Total-body vitamin A was assessed by the deuterated-retinol-dilution technique; liver vitamin A concentrations were assessed by assuming that liver weight is 2.4% of body weight and that, in this marginally nourished population, 70% of total-body vitamin A is in the liver; serum retinol was measured by HPLC; and dietary intakes were assessed with 3 nonconsecutive 24-h dietary recalls. The mean vitamin A intake + 2 SDs of subjects with adequate liver vitamin A concentrations was used to estimate an acceptable or sufficient vitamin A intake value for elders. Results: The mean (± SD) vitamin A intakes of the men and women with adequate vitamin A in liver were 135 ± 86 and 134 ± 104 μg retinol activity equivalents (RAE)/d, respectively; intakes of the men and women with low vitamin A in liver were 75 ± 53 and 60 ± 27 μg RAE/d, respectively. Total-body vitamin A or liver vitamin A but not serum retinol correlated with dietary RAE, preformed vitamin A, β-carotene, fat, and protein. An estimated acceptable or sufficient dietary vitamin A intake associated with adequate liver vitamin A concentrations in elders is 6.45 μg RAE/kg body wt; for a reference 76-kg man and a 61-kg woman, these values are ≈500 and 400 μg RAE/d, respectively. Conclusion: The dietary vitamin A intakes of elders with adequate or low liver vitamin A concentrations as estimated by use of the deuterated-retinol-dilution technique are useful for assessing vitamin A requirements. © 2004 American Society for Clinical Nutrition.