Vitamin megadose

The solubility (or insolubility) of different vitamins is of concern in nutrition. Molecules of vitamins B and C contain several —OH groups that can form hydrogen bonds with water (Figure 10.3). As a result, they are water-soluble, readily excreted by the body, and must be consumed daily. In contrast, vitamins A, D, E, and K, whose molecules are relatively nonpolar, are water-insoluble. These vitamins are not so readily excreted they tend to stay behind in fatty tissues. This means that the body can draw on its reservoir of vitamins A, D, E, and K to deal with sporadic deficiencies. Conversely, megadoses of these vitamins can lead to very high, possibly toxic, concentrations in the body. 

Pool concentration of a substance that exceeds the threshold - for example megadose vitamin C - or substances that are excreted unchanged because they cannot be metabolised, such as sugar alcohols, or compounds that are not biologically essential, such as carcinogens, bacterial toxins and some minor plant constituents, are also bioavailable (and thus bioactive) in that they have a metabolic impact, even if this is only the stimulation of detoxification processes, or the use of energy for their excretion. 

Complementary and alternative medicine CAM. Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices are not considered standard medical approaches. CAM includes dietary supplements, megadose vitamins, herbal preparations, special teas, massage therapy, magnet therapy, spiritual healing, and meditation. [NIH]... 

Johnston CS, Yen MF. Megadose of vitamin C delays insulin response to a glucose challenge in normoglycemic adults. Am J Clin Nutr 1994 60(5) 735-8. 

Each E, when the intake is null or insufficient, generates a disease, Increasing its quantity up to the required daily allowance (DA), the disease disappears. However, when E is given in excess it reaches the toxicity limit (TL). In case of vitamins and some minerals RDA are well defined, whereas TL is sometimes less clear, and the tendency is to misuse both in megadoses,... 

Herbert, V., Jacob, E., Wong, K. T. J., and Pfeffer, R. D., Low serum vitamin B12 levels in patients receiving ascorbic acid in megadoses Studies concerning the effect of ascorbate on radioisotope vitamin B12 assay. Am. ]. CUn. Nutr. 31, 253-258 (1978). 

Pauling finally wearied of trying to convince medical professionals about the benefits of megadoses of vitamin C and took his case directly to the public. His book, Vitamin C and the Common Cold, was a best seller. Sales of the vitamin soared. Nevertheless, his dispute with physicians persisted, with Pauling advocating for huge doses of vitamin C and the medical profession pooh-poohing his ideas. 

In conclusion, we have found that the presently set Recommended Dietary Allowances for riboflavin for women are inadequate even when they are not exercising, and that their riboflavin requirements are Increased by exercise. Weight reduction per se does not have an effect on riboflavin requirements. However, women who are exercising and on a weight reduction diet may get an inadequate amount of the vitamin because of their restricted food intake. We have no evidence, at least in the U.S., that athletes are at risk for clinical riboflavin deficiency. We do not think that it is necessary for those engaged in exercise to take megadoses of this B vitamin or of other B vitamins. 

Deficiencies of enzymes involved in the transformation of the vitamin pantothenic acid (64) into the cognate coenzyme forms (66, Fig. 7) result in severe developmental and neurological deflcits that affect few human patients (34, 72). Therapy with megadoses of pantothenic acid has been advocated, but their efficiency has yet to be demonstrated by stringent clinical studies (73). 

EXCESS There is concern about the possibility that certain susceptible individuals may develop renal stones or hemolytic anemia from megadoses of vitamin C. 

Auer BL, Auer D, Rodgers AL. Relative hyperoxaluria, crystalluria and haematuria after megadose ingestion of vitamin C. Eur J Clin Invest 1998 28(9) 695-700. 

An increased incidence of infection, even sepsis after intramuscular injection, as an adverse effect of megadose vitamin E therapy in very low birth weight infants was first reported in Japan in 1986 (SEDA-12, 330). In a review of the literature in 1992 it was concluded that pharmacological serum concentrations of vitamin E might predispose premature infants to infectious complications, possibly caused by an inhibitory effect of vitamin E on the formation of superoxide anion in leukocytes (27). 

Since vitamin overdose can produce unexpected, often vague, signs and symptoms, physicians should ask patients who present with inexplicable symptoms, including those listed in Table 2 (15), about their use of unusual or unapproved therapies, including vitamins in megadoses (10). It has been suggested that a medical history is not complete without vitamin/mineral supplement information (6). 

The use of megadoses of vitamin and mineral supplements has become common, and adverse effects can occur. 

Take megadoses of vitamins, so your body will have the strength to ward off the hangover. 

Chronic megadoses of vitamin C may precipitate formation of calcium oxalate renal stones, oxalate nephropathy, and renal failure. The amount required to cause this is variable from 2 to 8gday . Bone oxalate deposits have also been reported. Esophageal and dental erosion are possible with tablet ingestion. Heinz body hemolytic anemia has been seen in premature infants. 

Do not take megadoses of vitamin C with aspirin or sulfonamides. 

Megadoses of other vitamins (not proved effective against the rhinovirus)... 

A Tolerable Upper Intake Level (UL). The UL is the maximum intake by an individual that is unlikely to pose risks of adverse health effects in almost all (97-98%)individu-als. It includes intake of a nutrient from all sources (food, fortified food, water, and sup-dements). Water can include fluoride and minerals depending on the source of water. "Tolerable" is used to "avoid implying any possible beneficial effect." It is the amount of vitamin that can be "tolerated" without the person s exhibiting or experiencing adverse reactions. The UL should not be considered the upper dose for those who self-dose with megadoses of vitamins. 

Hypervitaminosis Pyridoxine. A certain mystique has built up around this vitamin, resulting in individuals overdosing themselves with commercial vitamin supplements. Serious neurological problems have been seen in doses of 2-6 g/day for 2 0 months (62-64). Megadosing below 2 glday seems safe, but all of this information is based mostly on anecdotal reports. There is a Tolerable Upper Intake Level, but the UL to RDA ratio is a comfortable 50-60. 

Hypervitaminosis B, 2. The vitamin is considered nontoxic. There has been some concern that the presence of the CN anion in the commercial vitamin might cause problems with megadoses. However, 1000 fig of cyan-ocobalamin contains only 0.02 mg of CN. There are no Tolerable Upper Intake Levels. 

Complementary (or alternative) medical approaches are used widely by women to treat menstruation-related disorders. " Daily supplementation of vitamins, minerals, and calcium, along with a well-balanced diet, is the first-line therapy for all menstruation-related disorders and helps to reduce deficiency states, particularly in peri-and postmenopausal women. Vitamin E supplementation in doses of 300 and 400 lU/day may be effective in relieving some premenstrual symptoms based on a few controlled studies.Over-the-counter products that contain megadoses of vitamins, as well as minerals and trace elements, have been marketed for PMS without chnical trials to document their effectiveness or safety. There are several brands of products for PMS (e.g., a combination preparation of a rmld diuretic. 

Vitamin status also may be affected by drugs (Table 135-15). For example, sulfasalazine therapy has been noted to cause a decrease in folic acid, isoniazid therapy causes pyridoxine deficiency, and furosemide therapy may result in decreased thiamin concentrations. Furthermore, some drug therapy outcomes may be affected by vitamin intake. The ingestion of megadoses of folic acid may decrease methotrexate s therapeutic effect, whereas changes in an individual s usual vitamin K intake may cause variability in warfarin s anticoagulation effects. 

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