To conduct an inpatient study on the recommended dietary allowance (RDA) for vitamin C, we developed a unique vitamin C deficient diet using a nutrient database and selective menus. Fourteen different menus were developed offering > 300 items with 0-2.4 mg vitamin C per serving. During the 4-6 mo volunteers were hospitalized, daily dietary vitamin C was restricted to ≤ 5.0 mg. The mean daily dietary vitamin C intake was < 3.9 mg for the seven study subjects. With concurrent supplementation, the diet provided ≤ 85% of the RDA for 17 essential nutrients. Within 3 wk of admission the diet induced vitamin C deficiency as indicated by plasma concentrations, which decreased from 23 ± 6.9 to 6.9 ± 2.0 μmol/L. Daily intake of vitamin C and five other nutrients was determined by nutrient database analyses. Mean energy, protein, and iron were 105-185% of the RDA and total and saturated fat were 32% and 10% of energy, respectively. Weight and nutritionally relevant indexes remained normal. Dietary adherence, calculated by the number of days with ≤ 5.0 mg vitamin C per total study days, was 88-98% per repletion dose. Computer analyses of menu selections permitted individual preferences to be met while restricting vitamin C intake to ≤ 5.0 mg/d. There were no complications from the diet during the depletion and repletion phases. With this diet, ascorbic acid pharmacokinetics for escalating doses could be determined in healthy volunteers.
CITATION STYLE
King, J., Wang, Y., Welch, R. W., Dhariwal, K. R., Conry-Cantilena, C., & Levine, M. (1997). Use of a new vitamin C-deficient diet in a depletion-repletion clinical trial. American Journal of Clinical Nutrition, 65(5), 1434–1440. https://doi.org/10.1093/ajcn/65.5.1434
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