Metabolic food disorders

All defects in urea synthesis result in ammonia intoxication. Intoxication is more severe when the metabolic block occurs at reactions 1 or 2 since some covalent linking of ammonia to carbon has already occurred if citrulline can be synthesized. Clinical symptoms common to all urea cycle disorders include vomiting, avoidance of high-protein foods, intermittent ataxia, irritability, lethargy, and mental retardation. The clinical features and treatment of all five disorders discussed below are similar. Significant improvement and minimization of brain damage accompany a low-protein diet ingested as frequent small meals to avoid sudden increases in blood ammonia levels. 

Mo use is not confined to prokaryotes similar enzymes are also formd in eukaryotes (including humans). Mo deficiency is rare, as are disorders of Mo metabolism, but symptoms may be induced if diets are rich in Cu or W, which are Mo antagonists. The direct toxicity of Mo is low, but Mo is an antagonist for Cu in cattle, where thiomolybdates formed in the rumen act as high-alfinity ligands for Cu. Hence intake of foods high in Mo can induce the disease molybdenosis (Mills and Davis 1987). 

L.B. Willett and C.P. Hodgson of Ohio State University, in collaboration with the U.S. Department of Agriculture, are currently investigating reproductive, metabolic, and nutritional disorders following heptachlor exposure from contaminated food in cattle (FEDRIP 1990). These investigators will also determine the cellular alterations that can influence reproductive or other homeostatic mechanisms. 

The main limitation to the clinical use of the MAOIs is due to their interaction with amine-containing foods such as cheeses, red wine, beers (including non-alcoholic beers), fermented and processed meat products, yeast products, soya and some vegetables. Some proprietary medicines such as cold cures contain phenylpropanolamine, ephedrine, etc. and will also interact with MAOIs. Such an interaction (termed the "cheese effect"), is attributed to the dramatic rise in blood pressure due to the sudden release of noradrenaline from peripheral sympathetic terminals, an event due to the displacement of noradrenaline from its mtraneuronal vesicles by the primary amine (usually tyramine). Under normal circumstances, any dietary amines would be metabolized by MAO in the wall of the gastrointestinal tract, in the liver, platelets, etc. The occurrence of hypertensive crises, and occasionally strokes, therefore limited the use of the MAOIs, despite their proven clinical efficacy, to the treatment of atypical depression and occasionally panic disorder. 

Chronic diseases and disorders of digestion, metabolism and immune function, such as chronic gastric ulcer, duodenal ulcer, food allergy and intolerance, hypotension, hypoglycemia, hypothyroidism, diabetes, chronic fatigue syndrome and prolapse of organs. 

Today aspartame is used in more than 6,000 food products. Aspartame is 160 times as sweet as sucrose based on mass equivalents. Approximately 16,000 tons are consumed annually on a global basis, with approximately 8,000 tons used in the United States and 2,500 tons in Europe. In the body aspartame is metabolized into its three components aspartic acid, phenylalanine, and methanol (Figure 11.1). Aspartic acid is a nonessential amino acid and phenylalanine is an essential amino acid. The condition called phenylketonuria (PKU) is a genetic disorder that occurs when a person lacks the enzyme phenylalanine hydroxylase and cannot process phenylalanine. This results in high phenylalanine blood levels that are metabolized into products one of these is phenylpyruvate, which contains a ketone group and... 

Sugar is one of the purest foods made, from natural sources, and has never been known to contain any toxic or harmful components. Intensive investigations by the U.S. Food and Drug Administration resulted in a book in 1986 on the health and safety factors of sugar (cane and beet) in the diet (18). The conclusion was that sugar has no deleterious effect on health in regard to heart disease, diabetes, or other metabolic disorder. 

The thyroid gland, located in the neck, absorbs much of the iodine that enters the body in food and drink. This image of the gland was obtained by giving a patient the radioactive isotope iodine-131. Such images are useful in diagnosing metabolic disorders. 

The relation of body weight development food intake is an important parameter in toxicology studies. Normal feed uptake connected with lower body weight body development can indicate an effect on feed utilization (metabolic disorders e.g. caused by hyper-thyreoidism) or vica versa hypo-thyreoidism in case of normal food intake but faster body weight development. 

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