VITAMIN-C DEPLETION IS ASSOCIATED WITH ALTERATIONS IN BLOOD HISTAMINEAND PLASMA-FREE CARNITINE IN ADULTS

Objective: The purpose of this study was to determine whether carnitin e metabolism or histamine degradation would be useful parameters for i nvestigating the optimal requirement for vitamin C. Methods: Twenty-tw o non-scorbutic subjects with subnormal vitamin C status (plasma vitam in C <28 mu mol/L) were placed on a metabolic diet low in vitamin C fo r 3 seeks and repleted with graded doses of vitamin C: 10, 30 and 60 m g vitamin C daily (group 1) or 10, 125 and 250 mg vitamin C daily (gro up 2) far weeks 1, 2 and 3, respectively. Fasting blood samples were c ollected weekly and analyzed for plasma vitamin C, plasma free carniti ne and blood histamine. Results: Group 1 subjects remained in a subnor mal vitamin C state throughout the 3-week study, and blood histamine a nd plasma free carnitine were not impacted by the experimental treatme nt. Plasma vitamin C in group 2 subjects rose significantly during the study, and these subjects finished the study with an ample Vitamin C status indicative of vitamin C intakes above the recommended dietary a llowance. Bath blood histamine and plasma free carnitine were inversel y related to vitamin C status in group 2 subjects. Conclusions: These data indicate that blood histamine and plasma free carnitine are alter ed in individuals with subnormal, non-scorbutic vitamin C status and p rovide evidence that metabolic changes independent of collagen metabol ism occur prior to the manifestation of scurvy. Thus utilizing scurvy as an end-point to determine vitamin C requirements may not provide ad equate vitamin C to promote optimal health and well-being.