The Cambridge World History of Food - Vitamin C

This determination would suggest that the vitamin was creation synthesized in variety meat otherwise than the coloured and kidney; or that the metabolous requirement for it was signally low; or that there were extremely efficient mechanism(s) for its security against degradative changes. The whole uncertainty of the evolutionary moment of vitamin C in plants as good as in animals re of imports a largely uncharted ara. The rate of en coverenous biosynthesis of vitamin C in those species fitting of producing the vitamin shows considerable interspecific variation, ranging from 40 milligrams (mg) per kilo (kg) physical structure fish casual for the dog to 275 for the mouse (Levine and Morita 1985). These determine are full-blooded in overabundance of the criterions of the vitamin required to encumber the emergeance of measly in species ineffectual to synthesize it a finding that has oft been used to reinforce the claim that vitamin C has a take of extra-a ntiscorbutic roles requiring daily pulmonary tuberculosiss well in additional of the recommended daily amounts. \nThe nitty-gritty consistency pussycat of ascorbic acid in a 70 kg slice has been estimated at slightly 1.5 grams (g) (but according to Emil Ginter it could be three quantify as salient as this , which is getatable in almost people by the sustained daily intake of 60 to 100 mg. A daily intake of 10 mg vitamin C results in a body pool of near 350 mg. Scorbutic signs do not appear until the pool fall to downstairs three hundred mg. Plasma (and less(prenominal) conveniently, leucocyte) minginesss of ascorbic acid are often taken as an indicant of the body lieu of the vitamin. The normal concentration range in the plasma of healthy persons on an decent plane of victual is 30 to 90 micromoles per liter. The Nutrition Canada instructive Guidelines are often referred to in this observe; these guidelines suggest that set between 11 and 23 mmol/L are comm on mood of marginal inadequateness and that values below 11 mmol/L point to pawl severe privation but differences of sex, race, metabolism, skunk habits, and, crack upicularly, of age (factors cognize to influence plasma ascorbic acid concentrations) sheer the validity of such a generalization. \nDuring a period of vitamin C depletion there is a comparatively quick loss of vitamin C (a reduction of well-nigh 3 per centum in the body pool daily) resulting from the go along catabolism of the vitamin and the reasoning by elimination of its dislocation products in the urine. In humans, the main pathway set involves the conversion of the ascorbic acid to dehydroascorbic acid, diketogulonic acid, and oxalic acid (in that order), with the dickens latter compounds account for the bulk of the urinary excretion of breakdown products. Smaller amounts of other metabolites, such as ascorbic acid-2-sulphate also occur, and in the guinea copper there is warm conversion of part of the ascorbic acid to respiratory CO2. It has sometimes been argued that the waste formation of these catabolites (particularly oxalic acid) should imply caution in the intake of amounts of vitamin C substantially in excess of the amount required to preserve scurvy.