Vitamin C been observed that while serum or blood plasma concentrations follow a circadian rhythm or reflect short-term dietary impact, content within tissues is more stable and can give a better view of the availability of ascorbate within the entire organism. However, very few hospital laboratories are adequately equipped and trained to carry out such detailed analyses. The vast majority of animals and plants are able to synthesize vitamin C, through a sequence of enzyme-driven steps, which convert monosaccharides to vitamin C. Yeasts do not make -ascorbic acid but rather its stereoisomer, erythorbic acid In plants, this is accomplished through the conversion
Vitamin C infection. The mega-dosing theory is to a large degree discredited. Modest benefits are demonstrated for the common cold. Benefits are not superior when supplement intakes of more than 1,000 mg/day are compared to intakes between 200 and 1,000 mg/day, and so not limited to the mega-dose range. The theory that large amounts of intravenous ascorbic acid can be used to treat late-stage cancer is - some forty years after Pauling's seminal paper - still considered unproven and still in need of high quality research. However, a lack of conclusive evidence has not stopped individual physicians from prescribing intravenous ascorbic acid