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Ascorbic acid vitamin high intakes

Tomato (Solarium lycopersicwn L.) is extensively cultivated worldwide, and its fruits have assumed the status of functional foods as a result of epidemiological evidence of reduced risks of certain types of cancers and cardiovascular diseases [180,181]. They are a reservoir of diverse antioxidant molecules, such as lycopene, ascorbic acid, vitamin E, carotenoids, flavraioids, and phenolics, and may provide a significant part of the total intake of beneficial phytochemicals, as a result of then-high consumption rates. Among carotenoids, lycopene has a strong antioxidant activity and is able to induce cell-to-ceU communications and modulate hormones, immune systems, and other metabolic pathways [182]. [Pg.2651]

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). [Pg.479]

Pregnancy Category C. Do not administer ascorbic acid to pregnant women in excess of the amount needed for treatment. The possibility of the fetus adapting to high levels of the vitamin could result in a scorbutic condition after birth when the intake drops to normal levels. This action is controversial. [Pg.5]

As would be expected from the very high concentrations of ascorbic acid maintained in the tissues, and as was found for the guinea pig, the intake of ascorbic acid per kilogram of body weight is more closely correlated with the plasma levels of children than the total intake of the vitamin (R15). Another study did not show this relationship (H4). [Pg.160]

The metabolic defect in tyrosine metabolism is therefore induced by the extra tyrosine fed and is not a necessary part of scurvy. The fact that it can be induced in animals whose tissues are less than saturated with ascorbic acid, but not in animals saturated with ascorbic acid, supports the value of high nutritional intakes of vitamin C. [Pg.168]

The tablets sold in pharmacies, which are used to prevent or treat colds, usually contain much larger amounts (200-1000 mg) of ascorbic acid. Could this high dose be harmful Does it make sense to exceed the physiologically necessary dosage or to take megadoses of vitamin C A general answer to the first question is given in a separate stoiy 3.14). For present purposes, it suffices to state that the approved ascorbic acid products are safe even if they contain several times of the recommended daily intake of vitamin C. [Pg.159]

Extrinsic labeling has been used in several studies to assess apparent copper absorption inhumans. This includes studies to evaluate apparent copper absorption from plant- and animal-based diets [263, 264], and also the effect of ascorbic acid [265], age [146, 266, 267], copper intake [267-271], zinc intake [146], and iron supplementation [272] on copper absorption. By measuring urinary excretion of the tracer, copper retention has also been assessed from vitamin B6-defident diets [271], in pregnant women [263], in young men consuming a low copper diet [268], and for high copper intakes [270]. [Pg.475]

As regards the use of vitamins in cancer prevention, as distinct from cancer treatment, there is no evidence that a vitamin intake above that required for normal nutrition provides extra protection. However, since vegetables contain /5-carotene, tocopherols, ascorbic acid and also considerable amounts of fibre, all of which are credited with beneficial effects, a high vegetable diet would seem to have much to recommend it. A list of some of the dietary factors currently believed to have either cancer-preventing or cancer-promoting effects is given in Table 12.2. [Pg.169]

About 3% of the body s vitamin C pool, which is 20-50 mg/kg body weight, is excreted in the urine as ascorbic acid, dehydroascorbic acid (a combined total of 25%) and their metabolites, 2,3-diketo-L-gulonic acid (20%) and oxalic acid (55%). An increase in excreted oxalic acid occurs only with a very high intake of ascorbic acid. Scurvy is caused by a dietary deficiency of ascorbic acid. [Pg.417]

Human milk from well-nourished women is relatively high in ascorbic acid, but it varies with the mother s dietary intake of the nutrient During lactation, a daily loss of 25 to 45 mg of vitamin C may occur in the secretion of 850 ml of milk. So, for lactating women, an additional allowance of 35 mg/day of vitamin C is recommended for the first six months in order to assure a satisfactory level of the vitamin in breast milk. [Pg.1096]


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