Vitamin Ascorbic acid deficiency

One-third of the amino acid residues in collagen are Gly, while another quarter are Pro. The hydroxylated amino acids 4-hydroxyproline (Hyp) and 5-hydroxylysine (Hyl) are formed post-translationally by the action of proline hydroxylase and lysine hydroxylase. These Fe2+-containing enzymes require ascorbic acid (vitamin C) for activity. In the vitamin C deficiency disease scurvy, collagen does not form correctly due to the inability to hydroxylate Pro and Lys. Hyl residues are often post-translationally modified with carbohydrate. 

Ascorbic acid. Vitamin C, is a water-soluble vitamin of great im-portance. A deficiency of vitamin C in the diet leads to scurvy, a disease characterized by loss of weight, general weakness, hemorrhagic condition of the gums and skin, loosening of the teeth, and other symp-toms. Sound tooth development seems to depend upon a satisfactory supply of this vitamin, and a deficiency is thought to cause a tendency to incidence of a number of diseases. 

Although the water-soluble vitamins are structurally diverse, they are put in a general class to distinguish them from the lipid-soluble vitamins. This cla.ss includes the B-complex vitamins and ascorbic acid (vitamin C). The term B-complex vitamins usually refers to thiamine, riboflavin, pyridoxine. nicotinic acid, pantothenic acid, hiotin. cyanocobalamin. and folic acid. Dietary deficiencies of any of the B vitamins commonly are complicated by deftciencies of another mem-ber(s) of the group,. so treatment with B-complex preparations is usually indicated. 

The answer is e. (Murray, pp 627-661. Sciiver, pp 3897-3964. Sack, pp 121-138. Wilson, pp 287-320.) Ascorbic acid (vitamin C) is found in fresh fruits and vegetables. Deficiency of ascorbic acid produces scurvy, the sailor s disease. Ascorbic acid is necessary for the hydroxylation of proline to hydroxyproline in collagen, a process required in the formation and maintenance of connective tissue. The failure of mesenchymal cells to form collagen causes the skeletal, dental, and connective tissue deterioration seen in scurvy. Thiamine, niacin, cobalamin, and pantothenic acid can all be obtained from fish or meat products. The nomenclature of vitamins began by classifying fat-soluble vitamins as A (followed by subsequent letters of the alphabet such as D, E, and K) and water-soluble vitamins as B. Components of the B vitamin fraction were then given subscripts, e.g., thiamine (Bi), riboflavin (B2), niacin [nicotinic acid (B3)], panthothenic acid (B5), pyridoxine (Bg), and cobalamin (B ). The water-soluble vitamins C, biotin, and folic acid do not follow the B nomenclature. 

Glucuronate, once formed, can reenter the pathways of glucose metabolism through reactions that eventually convert it to D-xylulose 5-phosphate, an intermediate of the pentose phosphate pathway. In most mammals other than humans, an intermediate of this pathway is the precursor of ascorbic acid (vitamin C). Humans, however, are deficient in this pathway and cannot synthesize vitamin C. 

Molybdenum deficiency sharply decreases the contents of ascorbic acid (vitamin C) in several crops, such as cauliflower (Agarwala and Hewitt, 1954b), leguminous plants (Avdonin and Arens, 1966), and potato tubers (Munshi and Mondy, 1988). The decreases in the content of ascorbic acid are more pronounced in the presence of NOs as the N source, but they also occur with NH4+ and other N sources (Hewitt and McCready, 1956). 

Vitamins are any organic dietary substance necessary for life, health, and growth that do not function by supplying energy. They usually function as coenzymes. Vitamins for one species may not be vitamins for another. Only humans, monkeys, and guinea pigs lack the ability to synthesize ascorbic acid (vitamin C), for instance. Indeed, bacteria in the gut synthesize some essential vitamins, which are absorbed in amounts sufficient to meet daily requirements. The administration of antibiotics for a long period of time could thus result in a vitamin deficiency of the bacterial host. 

Beer is well known as a source of several vitamins, in particular B vitamins. Nevertheless thiamine (Bi) content is quite low (Bamforth, 2002) and this relative thiamin deficiency can lead to stimulation of alcohol consumption (Forsander, 1998). Some beers may contain considerable level of ascorbic acid (vitamin C), particularly if it was used during beer production as an antioxidant agent (Preedy, 2009). 

The consequence of a deficiency of ascorbic acid (vitamin C) is scurvy. The earliest account of scurvy was perhaps written by the Egyptians in the Papyrus Elbers about 1550 B.c. For centuries, scurvy was a scourge of navies, armies, and explorers. The first appearance of the term scurvy in an English publication was in 1589 in the records of Richard Hakluyt. Another 344 years passed before the antiscorbutic factor (vitamin C) was isolated, characterized, and synthesized. In 1933, Haworth and Szent-Gyorgyi coined the name L-ascorbic acid to reflect the antiscorbutic properties of the vitamin. 

A severe deficiency of ascorbic acid (vitamin C) results in a specific disease called scurvy. The major lesions of scurvy are... 

More recently, Anderson et al. (1980) have reported a significant enhancement of PHA- and Con A-induced blast transformation in lymphocytes from humans given 1-3 g of ascorbic acid per day. In vitro, however, ascorbic acid has been noted to cause a dose-dependent inhibition of PHA-induc d blast transformation in human lymphocytes (Ramirez et al., 1979), suggesting an in vitro cytotoxic effect of ascorbic acid. Vitamin C deficiency has also been noted to diminish other T-lymphocyte-mediated activities, including allograft survival (Kalden and Guthy, 1972) and cell-mediated cytotoxicity (Anthony et al., 1979). 

Other nutrients and their deficiencies that can impact iron status, utilization, or anemia include vitamin A, folate, vitamin B12, riboflavin, and ascorbic acid (vitamin C). Improving iron status can also increase the utilization of iodine and vitamin A from supplements. On the other hand, it is increasingly recognized that simultaneous provision of iron and zinc in supplements may decrease the benefit of one or both of these nutrients. These complex micronutrient interactions and their implications for nutritional interventions are incompletely imderstood but have significant implications for population-based supplementation strategies. 

Ascorbic acid is very soluble in water and mainly excreted in the urine. No ascorbic acid is excreted during vitamin C deficiency. A minimum amount is lost in the feces, even after intake of gram dosages (154). 

Water-soluble vitamins removed by hemodialysis (HD) contribute to malnutrition and vitamin deficiency syndromes. Patients receiving HD often require replacement of water-soluble vitamins to prevent adverse effects. The vitamins that may require replacement are ascorbic acid, thiamine, biotin, folic acid, riboflavin, and pyridoxine. Patients receiving HD should receive a multivitamin B complex with vitamin C supplement, but should not take supplements that include fat-soluble vitamins, such as vitamins A, E, or K, which can accumulate in patients with renal failure. 

The synergistic effect observed in the presence of all three antioxidants implies that there is an interaction between the individual antioxidant components. The direct interaction of the a-tocopherol radical and ascorbic acid is already well established (Bisby and Parker 1995) and a study by Mayne and Parker (1989) on chicks deficient in vitamin E and selenium showed that the... 

The main value of ACU measurement is that it makes it possible to give a fast estimate of vitamin C deficiency because in healthy subjects ascorbic acid is about 90% of total ACU [33], A strong deficit of ACU, possibly due to vitamin C deficiency, was found in patients with breast tumors (Fig. 11). 

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