|Solon, Juan Antonio|
Submitted to: American Journal of Clinical Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2002
Publication Date: 3/3/2003
Citation: RIBAYA-MERCADO, J.D., SOLON, F.S., FERMIN, L.S., PERFECTO, C.S., SOLON, J.A., DOLNIKOWSKI, G.G., RUSSELL, R.M. DIETARY VITAMIN A INTAKES OF FILIPINO ELDERS WITH ADEQUATE OR LOW LIVER VITAMIN A STORES AS ASSESSED BY DEUTERATED-RETINOL-DILUTION METHOD: IMPLICATIONS FOR DIETARY REQUIREMENTS. AMERICAN JOURNAL OF CLINICAL NUTRITION. 79:633-641,2003. Interpretive Summary: The vitamin A requirements of elderly humans have not been studied previously. The current US recommended dietary allowances (RDAs) for vitamin A of 900 and 700 µg retinol activity coefficients (RAE) for men and women have been set to be the same for all adults ¿19 y of age. An RAE = 1 µg of dietary retinol (from animal food sources) or 12 µg of plant ß-carotene or 24 µg of other plant substances that can be converted into vitamin A in the body. However, since there have been no previous data regarding the vitamin A needs of elderly people, it is not known whether their vitamin A requirements are similar to or are different from those of younger adults. This cross-sectional study aimed to determine the vitamin A status and requirements of men and women who are ¿60 y old. Specifically, we aimed to determine the habitual dietary vitamin A intakes of elders with adequate or low liver vitamin A stores, using a value of ¿0.07 µmol vitamin A/g liver (¿20 µg/g) as being indicative of adequate liver reserves. The study was done among elders in two adjacent poor communities in rural Philippines where there was a good probability of finding elders with low liver vitamin A stores. Vitamin A reserves were assessed by a stable-isotope-dilution method, and dietary intakes of vitamin A by 3 non-consecutive 24-hour recalls using Philippine food tables. The average vitamin A intake of subjects with adequate liver vitamin A reserves was about 2 times greater than the intake of subjects with low liver vitamin A reserves. To maintain adequate liver vitamin A reserves in elderly men and women, daily intakes of 7.48 and 7.83 µg RAE per kg of body wt, respectively, are advisable; for a reference 76-kg man and 61-kg woman, these values are 568 and 478 µg RAE per day, respectively. Based on these results, the vitamin A RDAs for elderly Americans seem high. This study also showed that the total vitamin A reserves in the body was correlated with dietary intakes of vitamin A, ß-carotene, fat and protein, but not carbohydrates. Serum retinol was not correlated with any of these dietary intakes; serum retinol values remain in the normal range unless a severe depletion of body vitamin A stores is present.
Technical Abstract: 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 aimed to assess the dietary vitamin A intakes of elders with adequate (>0.07 µmol/g) or low (<0.07 µmol/g) liver vitamin A reserves in order to determine the vitamin A requirements for this age group. Design: Vitamin A reserves were assessed by the deuterated-retinol-dilution (DRD) procedure; serum retinol, by high-performance-liquid-chromatography (HPLC); and dietary intakes, by 3 non-consecutive 24-h recalls using Philippine food tables. Results: Serum retinol was significantly higher in men vs women, but not liver vitamin A concentrations. The mean vitamin A intake of subjects with adequate liver vitamin A reserves was 144 µg retinol activity equivalents (RAE)/d, which was ~2 times greater than intake of subjects with low liver vitamin A reserves. Total-body vitamin A stores were significantly correlated with dietary RAE (rS=0.42, P=0.001), preformed vitamin A (rS=0.35, P=0.01), trans-ß-carotene (rS=0.30, P=0.02), fat (rS=0.32, P=0.01), and protein (rS=0.25, P=0.05), but not carbohydrates (rS=0.09, P=0.49); serum retinol was not correlated with any of these dietary intakes. Conclusions: 1) An average adequate amount of total-body vitamin A in elders is ~0.276 mmol. 2) To maintain adequate liver vitamin A reserves (>0.07 µmol/g) in elderly men and women, dietary intakes of 7.48 and 7.83 µg RAE/kg of body wt, respectively, are advisable; for a reference 76-kg man and 61-kg woman, these values are 568 and 478 µg RAE/d, respectively.