The correlation between intakes of vitamin A and total‐body vitamin A stores assessed by the labeled‐retinol‐dilution method in American adults

To evaluate the relation between intakes of vitamin A, serum retinol concentrations, total‐body vitamin A stores (TBVAS) and liver vitamin A concentrations in the American adults, we recruited 34 American subjects (16F,18M) aged 57.3 ± 8.0y (44–71y). Subjects were given 8.9μmol (3mg) [ 13 C 8 ] retinyl acetate (vitamin A supplement). The labeled‐retinol‐dilution (LRD) technique (Furr‐Olson Equation) was applied to determine TBVAS. Nutrient intakes were assessed by three 24‐h dietary recalls per week. The correlations of TBVAS, serum retinol and retinyl palmitate with intakes of vitamin A were analyzed using Spearman rank‐order correlations. Our results showed that no significant correlation was found between dietary vitamin A intake with the serum concentration of retinol and with TBVAS/kg body wt. However, we observed that the correlation between serum retinyl palmitate response (7–9h after the supplement) to the labeled retinyl acetate dose and liver vitamin A concentration was ‐0.35 (P = 0.04). Further, subjects (n = 8) who stopped the intake of multivitamins one month before the experiment was started, showed a significantly higher TBVAS (1.59 ± 0.80 mmol) than those who never took multivitamins (0.80 ± 0.60 mmol, n = 26) (with dietary vitamin A intake from 17 to 1219 RE) (P < 0.05). Therefore, supplement of vitamin A affected TBVAS. (supported by USDA 1950‐51000‐065 and 99‐35200‐7564)