A new recommended dietary allowance of vitamin C for healthy young women

Abstract

The recently released Recommended Dietary Allowance of vitamin C for women, 75 mg daily, was based on data for men. We now report results of a depletion-repletion study with healthy young women hospitalized for 186 ؉͞؊ 28 days, using vitamin C doses of 30 -2,500 mg daily. The relationship between dose and steadystate plasma concentration was sigmoidal. Only doses above 100 mg were beyond the linear portion of the curve. Plasma and circulating cells saturated at 400 mg daily, with urinary elimination of higher doses. Biomarkers of endogenous oxidant stress, plasma and urine F2-isoprostanes, and urine levels of a major metabolite of F 2-isoprostanes were unchanged by vitamin C at all doses, suggesting this vitamin does not alter endogenous lipid peroxidation in healthy young women. By using Food and Nutrition Board guidelines, the data indicate that the Recommended Dietary Allowance for young women should be increased to 90 mg daily.

The efficacy of vitamin C supplementation on reducing total serum cholesterol in human subjects: a review and analysis of 51 experimental trials

“…However, it has been observed that plasma concentrations of vitamin C are completely saturated at doses of 400 mg daily and higher, producing a steady state plasma concentration of approximately 1.40 mg/dl in both males and females. 86,87 This finding is somewhat interesting in light of the fact that all but one of the studies in this review utilized doses of vitamin C that were greater than 400mg/day, and that the post experimental plasma concentrations for a majority of the groups (2 of every 3) exceeded 1.40 mg/dl. In normal healthy populations, which were used in these plasma saturation studies, it appears that 400mg/ day of vitamin C is adequate for plasma saturation.…”

Metadichol® Induced High Levels of Vitamin C: Case Studies

“…With increasing oral doses of vitamin C up to 1000 mg, Levine et al showed that plasma vitamin C concentration reaches a steady-state concentration (60 to 80 μ mol/L) in healthy young adults [19,20]. Once plasma ascorbic acid levels reach saturation, additional vitamin C gets excreted in the urine IV administration of vitamin C bypasses the intestines and high concentrations of ascorbic acid are achievable in the plasma; over time.…”

Inflammation in the vascular bed: Importance of vitamin C

“…The current recommended dietary daily allowances for vitamin C are 90 mg for men and 75 mg for women. At intakes of the vitamin above about 60 mg/d in both genders, ascorbate begins to appear in the urine (Levine et al, 2001). However, intakes of 250 mg/d and higher are required to saturate ascorbate concentrations in plasma and contents of white blood cells (Levine et al, 2001).…”

“…At intakes of the vitamin above about 60 mg/d in both genders, ascorbate begins to appear in the urine (Levine et al, 2001). However, intakes of 250 mg/d and higher are required to saturate ascorbate concentrations in plasma and contents of white blood cells (Levine et al, 2001). Although there are clear limits on the amounts of vitamin C that humans can retain, the current dietary recommendations do not provide tissue-saturating ascorbate concentrations.…”