Physiology Dietary Sources and Requirements

D A Bender, University College London, London, UK © 2005 Elsevier Ltd. All rights reserved.

Ascorbic acid is a vitamin (vitamin C) for only a limited number of species: man and the other primates, bats, the guinea pig, and a number of birds and fishes.

in other species ascorbic acid is not a vitamin, but is an intermediate in glucuronic acid catabolism, and its rate of synthesis bears no relation to physiological requirements for ascorbate. Species for which ascorbate is a vitamin lack the enzyme gulonolac-tone oxidase (EC and have an alternative pathway for glucuronic acid metabolism.

Ascorbic acid functions as a relatively nonspecific, radical-trapping antioxidant and also reduces the tocopheroxyl radical formed by oxidation of vitamin E. it has a specific metabolic function as the redox coenzyme for dopamine ^-hydroxylase and peptidyl glycine hydroxylase, and it is required to maintain the iron of 2-oxoglutarate-dependent hydroxylases in the reduced state.

Breaking Bulimia

Breaking Bulimia

We have all been there: turning to the refrigerator if feeling lonely or bored or indulging in seconds or thirds if strained. But if you suffer from bulimia, the from time to time urge to overeat is more like an obsession.

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