Nutritional factors

The relationship between nutrition and toxicology falls into three major categories (1) the effect of nutritional status on the toxicity of drugs and environmental chemicals, (2) the additional nutritional demands that result from exposure to drugs and environmental chemicals, and (3) the presence of toxic substances in foods (Parke and Ioannides 1981). 

Many different chemical compounds induce the MFO in the liver and other tissues. Induction of the MFO is associated with increased biosynthesis of new protein. The most potent inducers are substrates whose rates of metabolism are low so that they remain associated with the enzyme for long periods of time. In humans, severely limited protein intake is usually accompanied by inadequate intake of all other nutrients thus it is difficult to designate specific pathological conditions to protein deficiency per se. Protein 

Note Male rats fed for 28 d from weaning on diets of varying casein contents and then given an oral dose of pesticides. 

The effect of proteins on pollutant toxicity includes both quantitative and qualitative aspects. Experiments show that animals fed proteins of low biological value exhibited a lowered microsomal oxidase activity when dietary proteins were supplemented with tryptophan, the enzyme activity was enhanced. Alteration of xenobiotic metabolism by protein deprivation may lead to enhanced or decreased toxicity, depending on whether metabolites are more or less toxic than the parent compound. For example, rats fed a protein-deficient diet show decreased metabolism but increased mortality with respect to pentobarbital, parathion, malathion, DDT, and toxaphene (Table 6.4). On the other hand, rats treated under the same conditions may show a decreased mortality with respect to heptachlor, CC14, and aflatoxin. It is known that, in the liver, heptachlor is metabolized to epoxide, which is more toxic than heptachlor itself, while CC14 is metabolized to CC13, a highly reactive free radical. As for aflatoxin, the decreased mortality is due to reduced binding of its metabolites to DNA. 

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In 1922, Evans and Bishop named the animal nutritional factor essential of reproduction Vitamin E . In the 1960s, vitamin E was associated with antioxidant function. Twenty-five years later, vitamin E has been found to possess functions that are independent of its antioxidant and free radical scavenging ability. a-Tocopherol specific molecular mechanisms were discovered which are still under investigation. 

The microorganisms do not necessarily always form the same metabolites as humans in a similar manner, but they can be useful for studies of drug interactions, disposition, etc. [11]. Although there is no correlation between the mammahan and microbial isozymes, the mechanism involved in microorganisms is still unknown, but may be similar to that involved in animals. Additionally, the fungal metabohsm of the compounds is often affected by the concentration, nutritional factors, inducers, and environmental factors [12]. 

Anemia may be present in some patients due to impaired erythropoietin regulation, nutritional factors (vitamin E and iron malabsorption), or chronic inflammation. With chronic pulmonary disease, increased cytokine production can lead to shortened red blood cell survival, reduced erythropoietin response, and impaired mobilization of iron stores. 

Kargacin B, Volf V. 1989. Influence of nutritional factors on 239Np and 233Pa retention in weanling rats. Hum Toxicol 8 425-429. 

The toxicokinetic and toxicological behavior of lead can be affected by interactions with essential elements and nutrients (for a review see Mushak and Crocetti 1996). In humans, the interactive behavior of lead and various nutritional factors is particularly significant for children, since this age group is not only sensitive to the effects of lead, but also experiences the greatest changes in relative nutrient status. Nutritional deficiencies are especially pronounced in children of lower socioeconomic status however, children of all socioeconomic strata can be affected. 

Table 2-12. Effects of Nutritional Factors on Lead Uptake in Animals... 

Baltrop D, Khoo HE. 1975. The influence of nutritional factors on lead absorption. Postgrad Med J 51 795-800. 

Lucas SR, Sexton M, Langenberg P. 1996. Relationship between blood lead and nutritional factors in preschool children A cross-sectional study. Pediatrics 97(l) 74-78. 

The individual risk for drag inefficacy or drug toxicity is a product of the interaction of genes and the environment. Environmental variables include nutritional factors, concommittantly administered drugs, disease and many other factors in-... 

DePeters EI and Cant I P (1992), Nutritional factors influencing the nitrogen composition of bovine milk A review , Journal of Dairy Science, 75, 2043-2070. 

Ziegler RG, Blot WJ, Hoover R, Blattner WA and Fraumeni JF Jr. 1981. Protocol for a study of nutritional factors and the low risk of colon cancer in Southern retirement areas. Cancer Res 41 3724-3726. 

Much of the toxicological interest in cyanide relating to mammals has focused on its rapid lethal action. However, its most widely distributed toxicologic problems are due to its toxicity from dietary, industrial, and environmental factors (Way 1981, 1984 Gee 1987 Marrs and Ballantyne 1987 Eisler 1991). Chronic exposure to cyanide is correlated with specific human diseases Nigerian nutritional neuropathy, Leber s optical atrophy, retrobulbar neuritis, pernicious anemia, tobacco amblyopia, cretinism, and ataxic tropical neuropathy (Towill etal. 1978 Way 1981 Sprine etal. 1982 Beminger et al. 1989 Ukhun and Dibie 1989). The effects of chronic cyanide intoxication are confounded by various nutritional factors, such as dietary deficiencies of sulfur-containing amino acids, proteins, and water-soluble vitamins (Way 1981). 

Casadei, E., P. Jansen, A. Rodrigues, A. Molin, and H. Rosling. 1984. Mantakassa an epidemic of spastic paraparesis associated with chronic cyanide intoxication in a cassava staple area of Mozambique. 2. Nutritional factors and hydrocyanic acid content of cassava products. Bull. World Health Org. 62 485-492. 

It was noted, however, that legume seeds contain anti nutritional factors such as trypsin inhibitors and lectins which exert... 

Psychoneuroses involving depression, irritability, anxiety, increased sensitivity to noise and painful stimuli, and uncertainty of memory have been induced in human patients as a result of thiamine deficiency. 22 It seems probable that the Wernicke type syndrome, which is more severe, can likewise be caused by thiamine deficiency. In all cases the psychological symptoms are eliminated or prevented by the administration of adequate amounts of thiamine. Here again is a clear-cut case in which mental disease can be caused by a nutritional deficiency and cured by supplying adequate amounts of the missing nutritional factor. 

Nutritional factors may influence the toxicity of pesticides. Research in this area has primarily focused on the role of dietary proteins, particularly sulfur-containing amino acids, trace minerals, and vitamins A, C, D, and E. Studies in rats show that inadequate dietary protein enhances the toxicity of most pesticides but decreases, or fails to affect, the toxicity of a few. The results of these studies have shown that at one-seventh or less normal dietary protein, the hepatic toxicity of heptachlor is diminished as evidenced by fewer enzyme changes (Boyd 1969 Shakman 1974). The lower-protein diets may decrease metabolism of heptachlor to heptachlor epoxide. 

Studies are needed to clarify the importance of age, sex, ethnicity, familial elements, nutritional factors, and pharmacologic agents in determining response to oxidants. Because people with lung disease are thought to be more susceptible to oxidant pollutants, exposure studies are needed to quantify this. Better methods for measuring or estimating the actual dose of oxidants absorbed by each subject are needed. The usual time variation in measures of human response should be evaluated... 

Nutritional factors such as a poor or an unbalanced diet may influence the intake and probably also the biotransformation of food contaminants. Ethnic differences due to variations in, e.g., dietary habits have also been reported (KEMI 2003). 

Nestle Nutrition Services. (1999). Normal microbial flora of the gut and the immune system. In "Probiotics, Other Nutritional Factors, and Intestinal Microflora." (Lars A. Hanson and Robert H. Yolken, eds.), pp. 217-228. Lippincott-Raven, Philadelphia. 

Riboflavin Nutritional factor found in milk, eggs, malted barley, Hver, kidney, heart, and leafy vegetables. The richest natural source is yeast. It occurs in the free form only in the retina of the eye, in whey, and in urine its principal forms in tissues and cells are as FMN and FAD. [nih]... 

Serum homocysteine concentration. The influence of nutritional factors associated... 

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