Vitamin intake

Of the water-soluble vitamins, intakes of nicotinic acid [59-67-6] on the order of 10 to 30 times the recommended daily allowance (RE)A) have been shown to cause flushing, headache, nausea, and moderate lowering of semm cholesterol with concurrent increases in semm glucose. Toxic levels of foHc acid [59-30-3] are ca 20 mg/d in infants, and probably approach 400 mg/d in adults. The body seems able to tolerate very large intakes of ascorbic acid [50-81-7] (vitamin C) without iH effect, but levels in excess of 9 g/d have been reported to cause increases in urinary oxaHc acid excretion. Urinary and blood uric acid also rise as a result of high intakes of ascorbic acid, and these factors may increase the tendency for formation of kidney or bladder stones. AH other water-soluble vitamins possess an even wider margin of safety and present no practical problem (82). 

S. K. Gaby, A. Bendich, V. N. Singh, and L. J. Machlin, Vitamin Intake and Health H Scientific Keview Marcel Dekker, New York, 1991. 

Vitamin Deficiency. Vitamin deficiency is uncommon in normal adults. However, when it does occur, it can be serious, particularly in pregnant women. Some vitamin deficiency can occur because of a large reduction of fat intake, which decreases absorption. Strict vegetarians also risk reduced vitamin intake. Premature infants and elderly people who are exposed to minimal sunlight and consume Htde vitamin also have a reduced capacity to metabolize and can develop vitamin deficiency. 

Fosamax plus D) 10 mg daily, 70 mg tablet 70 mg tablet with vitamin intake-long T1/2 (<10 years) ... 

Mega vitamin intake of vitamin C may result in diarrhea due to intestinal irritation. Since ascorbic acid is partially metabolized and excreted as oxalate, renal oxalate stones may form in some patients. 

Of the water-soluble vitamins, intakes of nicotinic acid on the order of 10 to 30 times the recommended daily allowance (RDA) have been shown to cause Hushing, headache, nausea, and moderate lowering ol serum... 

Luchsinger J. A., Tang M. X., Shea S., and Mayeux R. (2003). Antioxidant vitamin intake and risk of Alzheimer disease. Arch. Neurol. 60 203-208. 

Table 38-2 summarizes the key aspects of vitamins needed throughout the body. Most of these vitamins cannot be synthesized within the body and must be ingested from an outside source.76 Eating certain foods on a regular basis will provide the body with an adequate supply of the specific vitamins it needs. Fruits and vegetables, for example, often serve as a source of dietary vitamins. Alternatively, there are myriad vitamin supplements that consumers can purchase and self-administer to insure adequate daily vitamin intake. 

Clinicians should therefore advise patients about the need for adequate dietary vitamin intake, but should also caution patients about the indiscriminate or excessive use of vitamin supplements. Patients with... 

Hodis, H.N., Mack, W.J., LaBree, L., Cashin-Hemphill, L., Sevanian, A., Johnson, R., and Azen, S.P. 1995. Serial coronary angiographic evidence that antioxidant vitamin intake reduces progression of coronary artery atheroscloresis. JAMA 273, 1849-1854. 

The dimension of standard error is such that many subjects are not reaching the Recommended Dietary Daily Allowance (RDA) and consequently they need to increase the vitamins, intake either with food or supplements. On the other hand, many subjects take a very high amount of vitamins with the food. In these last cases a further intake through supplements could generate the condition of a pro-oxidant effect. 

Knekt R Reunanen A, Jarvine R, et al. Antioxidant vitamin intake and coronary mortality in a longitudinal population study. Am J Epidemiol 1994 138 1 180-1 189. 

Table 9-2 Contributions (%) of Various Food Groups to the Vitamin Intake of Americans...

Although modern analytical techniques have considerable precision and sensitivity, food composition tables carmot be considered to give more than an approximation to vitamin intake. Apart from the problems of biological availability (Section 1.1.2), there is considerable variation in the vitamin content of different samples of the same food, depending on differences between varieties, differences in growing conditions (even of the same variety), losses in storage, and losses in food preparation. 

Metabolic loading tests and the determination of enzyme saturation with cofactor measure the ability of an individual to meet his or her idiosyncratic requirements from a given intake, and, therefore, give a nearly absolute indication of nutritional status, without the need to refer to population reference ranges. A number of factors other than vitamin intake or adequacy can affect responses to metabolic loading tests. This is a particular problem with the tryptophan load test for vitamin Be nutritional status (Section 9.5.4) a number of drugs can have metabolic effects that resemble those seen in vitamin deficiency or depletion, whether or not they cause functional deficiency. 

Lovell MA, Robertson ID, Teesdale WJ, Campbell JL, Markesbery WR (1998) Copper, iron and zinc in Alzheimer s disease senile plaques. J Neurol Sci 158 47-52 Lu Z, Nie G, Li Y, Soe-Lin S, Tao Y, Cao Y, Zhang Z, Liu N, Ponka P, Zhao B (2009) Overexpression of Mitochondrial Ferritin Sensitizes Cells to Oxidative Stress Via an Iron-Mediated Mechanism. Antioxid Redox Signal 11(8) 1791-1803 Luchsinger JA, Tang MX, Shea S, Mayeux R (2003) Antioxidant vitamin intake and risk of Alzheimer disease. Arch Neurol 60 203-208... 

An epidemiological study supports the connection between low intakes of folate and of vitamin with cardiovascular disease. The study involved 80,082 women who were followed for 14 years. Vitamin intake was estimated by questionnaires, while the eventual acquisition of disea.se was determined by physicians who reviewed medical records. Although no biochemical tests were perfomned, it should be noted that this and other epidemiological studies acquire their power by their large number of subjects, as w ell as by small pilot studies that validate the accuracy of the questionnaires fkimm cf al., 1998). 

The diet contains an almost infinite number of foreign chemicals, and the enzymes of drug biotransformation probably evolved to cope with these chemicals. Consequently they were already available to deal with subsequently developed drugs. The activities of these enzymes can be affected by dietary constituents that may serve to increase or decrease them or cause both effects in alcohol ingestion, enzyme activities show a short-term decrease (inhibition) and then increase (induction). They can also be affected by nutritional status and reflect protein, fat, carbohydrate, mineral, and vitamin intake. 

A number of studies have suggested an association between elevated plasma vitamin E levels and reduced risk for cardiovascular disease (Bonithon-Kopp et ah, 1997 Gey, 1998 Rimm et ah, 1993 Stampfer et ah, 1993). The task of the nutritionist attempting to correlate vitamin intake with cardiovascular disease is complicated by the fact that different food oils contain different amounts of the various toco-pherols. Olive oil contains about 120 mg a-tocopherol/kg oil soybean oil (70 mg a-tocopherol and 900 mg y-tocopherol/kg) safflower oil (340 mg a-tocopherol and 35 mg y-tocopherol/kg) and wheat germ oil (1500 mg a-tocopherol and 800 mg y-tocopherol/kg) (Chase et ah, 1994 McLaughlin and Weihrauch, 1979). Most of the vitamin E present in blood plasma is a-tocopherol (rather than y-tocopherol, for example) because of the influence of a-tocopherol transfer protein. Most of the plasma vitamin E resides in the LDLs. A paradox seems to present itself where people who have elevated LDLs (and who are more at risk for cardiovascular disease) should also have elevated a-tocopherol (and possibly be at lesser risk for cardiovascular disease). This paradox can be avoided by expressing plasma a-to-copherol levels as a-tocopherol/cholesterol (Gey, 1998). 

It changes slowly in response to changes in vitamin intake. 

It tends to reflect recent vitamin intake rather than general vitamin status. 

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