Vitamin nutritional status

JB Ubbink. Vitamin nutrition status and homocysteine an atherogenic risk factor. Nutr Rev 52 383-387, 1994. 

The same criteria used to define requirements can also be used to assess vitamin nutritional status. 

The tryptophan load test for vitamin Bg nutritional status (the ability to metabolize a test dose of tryptophan) is one of the oldest metabolic tests for functional vitamin nutritional status. It was developed as a result of observation of the excretion of an abnormal-colored compound, later identified as the tryptophan metabolite xanthurenic acid. 

AS. Ahmed, F., Bamji, M. S., and Iyengar, L., Effect of oral contraceptive agents on vitamin nutrition status. Am. J. Clin. Nutr. 28, 605-615 (1975). 

Xanthurenic and kynurenic acids, and kynurenine and hydroxykynurenine, are easy to measure in urine, so the tryptophan load test (the ability to metabolize a test dose of 2—5 g of tryptophan) has been widely adopted as a convenient and very sensitive index of vitamin nutritional status. However, because glucocorticoid hormones increase tryptophan dioxygenase activity, abnormal results of the tryptophan load test must be regarded with caution, and cannot necessarily be interpreted as indicating vitamin B deficiency. Increased entry of tryptophan into the pathway will overwhelm the capacity of kynureninase, leading to increased formation of xanthurenic and kynurenic acids. Similarly, oestrogen metabolites inhibit kynureninase, leading to results that have been misinterpreted as vitamin B deficiency. 

Maximizing nutritional status through pancreatic enzyme replacement and vitamin and nutritional supplements is necessary for normal growth and development and for maintaining long-term lung function. 

However, results obtained by Koo et al. (1991) indicate that low to moderate lead exposure (average lifetime PbB level range of 4.9-23.6 pg/dL, geometric mean of 9.8 pg/dL, n=105) in young children with adequate nutritional status, particularly with respect to calcium, phosphorus, and vitamin D, has no effect on vitamin D metabolism, calcium and phosphorus homeostasis, or bone mineral content. The authors attribute the difference in results from those other studies to the fact that the children in their study had lower PbB levels (only 5 children had PbB levels >60 pg/dL and all 105 children had average lifetime PbB levels <45 pg/dL at the time of assessment) and had adequate dietary intakes of calcium, phosphorus, and vitamin D. They concluded that the effects of lead on vitamin D metabolism observed in previous studies may, therefore, only be apparent in children with chronic nutritional deficiency and chronically elevated PbB levels. Similar conclusions were reached by IPCS (1995) after review of the epidemiological data. 

Parvin, S. G. and B. Sivakumar. 2000. Nutritional status affects intestinal carotene cleavage activity and carotene conversion to vitamin A in rats. J Nutr 130(3) 573-577. 

Acute toxicity of paraquat in the domestic chicken was highly responsive to nutritional selenium status and not to Vitamin E status. As little as 0.01 mg Se/kg ration protected 8-day-old chicks against acute paraquat poisoning (Combs and Peterson 1983). Paraquat administered to chickens by way of diet was less toxic than the same amount administered in drinking water (Fletcher 1967). 

When the alcoholic first presents for treatment, his/her nutritional status should be fully assessed. Vitamin supplementation should always be a component of this treatment. In the emergency room setting, the alcoholic patient usually receives intravenous fluids containing magnesium, thiamine, and multivitamin supplements. The yellow-colored fluid is commonly called a banana bag or rally pack. A daily... 

Nutritional status can also influence the toxic potency of carbon tetrachloride. Animal studies have clearly demonstrated that brief fasting or consumption of diets low in antioxidants (vitamin E, selenium, methionine) can lead to increased carbon tetrachloride hepatotoxicity. The same may be true for humans, although this is not known for certain. Another aspect of nutritional status affecting carbon tetrachloride toxicity is hepatic energy status. Hepatic ATP levels might influence the ultimate outcome of toxicity (low levels may inhibit recovery mechanisms). 

Deficiency syndromes of Zn, Cu, Cr, Se and Mo have occurred in patients on total parenteral nutrition (TPN). There is still much research to be done in assessing the nutritional status of many elements and understanding their metabolism, so that normal dietary intake may be supplemented for health benefits. Table 2 is a summary of the amounts required, the functions and the nutritional (usually dietary) imbalances in humans, where known, of the essential trace elements.31-33 (Note that this summary does not attempt to include imbalances related to environmental toxicology and occupational hazards.) Several trace elements have important functions in the immune system. Some are associated with nucleic acid. Others have structural roles, such as Si in cartilage, F and Zn in bone. They may be parts of vitamins, such as Co in vitamin B12, or hormones, such as iodine in thyroid hormones, Zn and Cr have a role in the synthesis and action of insulin.31-33... 

Abbreviations CA, carotid atherosclerosis CPIHD, Caerphilly Prospective Ischemic Heart Disease EVCS, Elderly Vitamin C Status IWHS-D, Lowa Women s Health Study MGH, Mortality in a Geriatric Hospital MRCT Medical Research Council Trial NAHNES I, National Health and Nutrition Examination Survey PSCHD, Prospective Study of vitamin C in Coronary Heart Disease SOP Supplementation... 

Increasing evidence indicates that diet/nutrition plays an important role in modulating the action and/or metabolism of a number of chemicals, drugs and environmental pollutants. Nutrients are essential for all fundamental cellular processes. The nutritional status of the affected subject may, therefore, influence cellular susceptibility to the effect of xenobiotics, including those from cigarette smoke. While the precise role of vitamin E in cellular metabolism is not yet clear, the vitamin may protect essential cellular components from the adverse effects of xenobiotics either via a free radical scavenging mechanism or as a component of the cell membrane (10-11). Administration of vitamin E has been shown to lessen the toxicity of a variety of compounds (12-16). 

It is well established that vitamin A deficiency (VAD) is a public health problem in more than ioo countries, especially in Africa and Southeast Asia, hitting hardest young children and pregnant women. Worldwide, over 124 million children are estimated to be vitamin A deficient. Many of these children go blind or become ill from diarrhea, and nearly eight million preschool age children die each year as the result of this deficiency. The World Health Organization estimates that improved vitamin A nutritional status could prevent the deaths of 1.3—2.5 million late-infancy and preschool age children each year (Humphrey et al. 1992). The heartache of losing a child to a preventable disease is not one commonly encountered in the developed world. 

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