Diet and Health Implications for Reducing Chronic Disease Risk (1989) / Chapter Skim
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12 Water-Soluble Vitamins
12 Water-Soluble Vitamins
Pages 329-346
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From page 329... ...
NHANES I} the National Health and Nutrition Examination Survey, conducted from 1976 to 198Windicated that 3% of the respondents 3 to 74 years of age had low serum vitamin C levels. Therefore, the Joint Nutrition Monitoring Evaluation Committee concluded that this vitamin should be accorded high-priority status for future monitoring (DHH~USDA, 1986~.
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From page 330... ...
Nia~n In nutrition literature, the term niacin is used generically to encompass the active forms of this vitamin, nicotinic acid and nicotinamide; however, estimates of niacin rec~uirements take into account preformed niacin as well as that obtained as equivalent (NE) in the bocly from tryptophan metabolism.
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From page 331... ...
EVIDENCE ASSOCIATING WATER-SOLUBLE VITAMINS WITH CHRONIC DISEASES Vitamin C Cancer Human Studies In epidemiologic studies, the association of vitamin C with cancer is mostly indirect, since it is based on the consumption of .fosdrs known to contain high or low concentrations of the vitamin rather than on measured ingestion of ascorbic acid. Meinsma (1964)
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From page 332... ...
Animal Studies Ascorbic acid has been reported to prevent the formation of N-nitroso compounds (Mirvish, 1981a; Tannenbaum and Mergens, 19801. Vitamin C is postulated tO act by the reduction of nitrite, ultimately preventing formation of nitrosamine or nitrosourea as demonstrated in vitro.
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From page 333... ...
ir~duced colon cancer in rats was not influenced by dietary vitamin C (Ready et al., 1982~. High doses of ascorbic acid administered in the drinking water had no effect on the growth of transplantable mammary tumors induced by dimethy~benzanthracene in rats (Abul-Hajj and Kelliher, 1982~.
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From page 334... ...
More recently, diets mar DIET AND HEALTH Anal or deficient in riboflavin, nicotinic acid, magnesium, and zinc have been correlated with esophageal cancer (Thumham et al., 1982; van Rensburg et al., 1986~. Riboflavin deficiency has also been reported to cause possibly precancerous lesions in the esophageal epithelium of humans (Foy and Mbaya, 1977~.
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From page 335... ...
The lower urinary levels and clearance in cancer patients could be due in part to increased plasma binding rather than trapping by tumor tissue. Liver Disease Human Studies Ethanol consumption can reduce intestinal bioavailability of riboflavin, particularly flavin adenine dinucleoti`de (FAD)
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From page 336... ...
The effects of nicotinamide may be due to increasing the NAD pools, which are depleted by certain carcinogens (Rakieten et al., 1971; Schoental, 1975~. Infer Disease Human Studies The human liver contains approximately 60 mg of nicotinic acid (free and covalently bound incoenzymes)
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From page 337... ...
Liver Disease Human Studies Although there is no consensus on the best biochemical marker for the assessment of vitamin B6 status in humans, plasma PEP is the one most frequently used (Williams et al., 1984~. Most dietary vitamin B6 is rapidly converted by the liver to this active coenzyme form, which has ~ central role in the metabolism of amino acids.
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From page 338... ...
Severe lipidosis and cell death result from methyl group-deficient diets (Ghoshal et al., 1983; Giambarresi et al., 1982; Shinozuka and Lombardi, 1980~. Liver Disease Human Studies Folate deficiency in alcoholics is likely to be caused by impaired intestinal uptake as well as by decreased storage in the damaged liver (Halsted and Tamura, 1979; HilIman, 1980~.
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From page 339... ...
Over Disease Human Studies The intake of ethanol affects the storage of vitamin BY in the liver. Vitamin BY deficiency is not common in alcoholics, as indicated by normal serum B:2 levels in patients with folate deficiency, both with and without cirrhosis (Halsted et al., 1971; Herbert et al., 1963~.
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From page 340... ...
Over Disease Human Studies Because pantothenic acid concentrations are several times higher in the liver than in other tissues, the liver is affected by nutritional intake more than other organs. Spontaneous gross pantothenic acid deficiency in humans has seldom been described, although Olson (1984)
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From page 341... ...
Epidemiologic data derived primarily from China indicate that low riboflavin levels may be associated with a greater risk of esophageal cancer. These data are supported by similar results in animal studies.
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From page 342... ...
1979. Oesophageal cancer studies in the Caspian Littoral of Iran: results of a casecontrol study.
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From page 343... ...
1977. Esophageal cancer studies in the Caspian Littoral of Iran: results of population studie~a prodrome.
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From page 344... ...
1986. Ascorbic acid and cholesterol levels in patients with diabetes mellitus and coronal arter, disease.
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From page 345... ...
1980. Leukocyte ascorbic acid and its relationship to coronary artery disease in man.
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From page 346... ...
1982. Riboflavin, vitamin A and zinc status in Chinese subjects in a high~risk area for oesophageal cancer in China.
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