Verification of L-Ascorbie-1-C 14 Acid Catabolism to Carbon 14 Dioxide in the Human by Liquid Scintillation Counting

Abstract

Conclusion

As previously pointed out in the literature, a certain portion of ascorbic acid administered to the human could not be accounted for before the availability of radioactive compounds (13,14). We have shown that this unknown balance can now be accounted for as carbon dioxide excreted in the exhaled air. The catabolism of ascorbic acid is relatively slow in the human. An appreciable amount of radioactive ascorbic acid must therefore be ingested in order that the ca-tabolized carbon dioxide can be detected in man. It is therefore necessary to ingest quantities in the range of 1 μc of L-ascorbic-1-C¹⁴ acid per lb of body weight to measure ca-tabolized C¹⁴O₂ in the expired air with an ionization chamber or a liquid scintillation spectrometer. Important contributions to human nutrition and the nutritional requirements of vit C may be derived from the demonstration of this new human excretory pathway in the catabolism of ascorbic acid.