Metabolism dietary factors

Substantial individual differences were observed in the response to study breads and the ranges of enterolactone concentration changes in the groups were as follows -54.5-60.0 nmol/1 (placebo), -26.2-101.3 nmol/1 (LP), -19.6-81.8 nmol/1 (HP). This was something that could have been expected as in several studies dietary factors have explained only 10% of the variation in serum enterolactone (Vanharanta et al, 2002b Kilkkinen et al., 2001). This gives further support to the major role of intestinal bacteria in the synthesis of enterolactone. Decreased concentrations of enterolactone may occur due to an increased fiber intake, which may shorten the retention time in the colon and lead to incomplete metabolism of plant lignans. Constipation was earlier shown to be associated with an increased level of serum enterolactone (Kilkkinen et al., 2001). 

A number of dietary and nondietary variables have been proposed as risk factors for osteoporosis. Among dietary factors, the relation between caffeine intake and bone health has been studied extensively. Although proof that caffeine adversely affects calcium metabolism and is detrimen-... 

The enzyme mediating remethylation, 5-methyltetrahy-drofolate-betaine methyltransferase (Fig. 40-4 reaction 4), utilizes methylcobalamin as a cofactor. The kinetics of the reaction favor remethylation. Faulty remethylation can occur secondary to (1) dietary factors, e.g. vitamin B12 deficiency (2) a congenital absence of the apoenzyme (3) a congenital inability to convert folate or B12 to the methylated, metabolically active form (see below) or (4) the presence of a metabolic inhibitor, e.g. an antifolate agent that is used in an antineoplastic regimen. 

The present communication is concerned with calcium balance studies carried out during the Intake of a variety of dietary factors including minerals and protein as well as drugs. The studies were performed In adult males under strictly controlled conditions in the Metabolic Research Unit. The diet was kept constant throughout the relatively long term studies and complete collections of urine and stool were obtained. The composition of this diet was previously described (5). The diet and the excretions in urine and stool were analyzed for calcium throughout the studies. These data formed the basis of calcium balances which were determined for several weeks. Calcium was analyzed by atomic absorption spectroscopy (6). 

The greater rate of metabolism (shorter half-life, increased clearance) in the Caucasians was ascribed at least in part to the influence of dietary factors such as eating meat and exposure to coffee, cigarette smoke, and alcohol in the Caucasians. 

Cambell TC, Hayes JR, Merrill AH, et al. The influence of dietary factors on drug metabolism in animals. Drug Metab Rev 1979 9 173. 

In humans 100 or more years in age some mitochondrial mutations are associated with good health and longevity.541 Dietary factors doubtless play a role. For example, supplementation of rats diet with lipoic acid improved mitochondrial function and increased the metabolic rate of old animals.542... 

During the course of the symposium, several dietary factors that can influence xenobiotic metabolism were discussed in detail. Here we will attempt t summarize in the broadest terms how various classic nutrient groups might exert an influence on xenobiotic metabolism. For convenience, the dietary groups have been broken into carbohydrates, lipids, proteins, water-soluble vitamins, fat-soluble vitamins and trace elements. It is difficult to take any one group individually, and it must be kept in mind that the interactions are continuous and extremely complicated. 

In summary, it is clear that a multitude of dietary factors can Influence the metabolism of xenobiotics, particularly those that can be involved in carcinogenesis. We are and will continue to be exposed to xenobiotics of various types from our food, industrial sources, toxic wastes, drugs, and smoke. The well nourished animal or man appears, within the limits of individual variation, to be able to metabolize and excrete most of these xenobiotics harmlessly. It is important that we use the best diet possible to reduce fat in the diet, particularly where lipid... 

To What Extent Do Dietary Factors Contribute to Interindividual Variations in Drug Metabolism ... 

This discussion of starvation illustrates the complex problems of interpreting the results of even well controlled experiments on single dietary manipulations. It also shows the difficulties of extrapolating results from one set of environmental conditions to another. Clearly, such extrapolation is hazardous in assessing the contribution of any single dietary factor to large interindividual variations in metabolism of model drugs. Other approaches must be... 

Absorption in rat liver, conjugated diene, various choline diets, 332f Absorption spectrum of the DNA adduct and reaction mixture, 105 Acetaminophen, effect of dietary factors on metabolism, 62... 

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