Vitamins metabolism, disorders

Reference Intakes (DRIs). In the past, the recommended dietary allowances (RDAs), which are the levels of intake of essential nutrients that are considered to be adequate to meet the known nutritional needs of practically all healthy persons, were the primary reference value for vitamins and other nutrients. The DRIs also include other reference values, such as the estimated average requirement (EAR) and the adequate intake (AI). The RDA, EAR, and AI reference standards define nutritional intake adequacy. Since these recommendations are given for healthy populations in general and not for individuals, special problems, such as premature birth, inherited metabolic disorders, infections, chronic disease, and use of medications, are not covered by the requirements. Separate RDAs have been developed for pregnant and lactating women. Vitamin supplementation may be required by patients with special conditions and for those who do not consume an appropriate diet. 

Significant medical conditions, including head trauma, metabolic disorders, and neurologic conditions, should be identified. Eating and sleeping patterns are important to identify over time to know if these relate to the present condition and to know if medications affected them. Information about potential drug sensitivities or interactions may be obtained from a medication history that includes antibiotics commonly used, cold preparations, vitamins, health supplements, and present and past psychotropic medications. It is important to find out about previous medication trials what was tried, what worked, what did not work, and why. 

Anyone with the condition phenylketonuria (PKU), a metabolic disorder, should be particularly careful about nitrous oxide use. Individuals with PKU require a diet that is high in protein in low in animal fats, which frequently results in a vitamin B12 deficiency. Nitrous oxide can remove even more B12 from these individuals bloodstreams, possibly causing mental impairments, as well as severe nerve and brain damage. 

MawerEB and Davies M (2001) Vitamin D nutrition and hone disease in adults. Reviews of Endocrine and Metabolic Disorders 2, 153-64. 

Kawada T, Kamei Y, and Sugimoto E (1996) The possibility of active form of vitamins A and Das suppressors on adipocyte development via ligand-dependent transcriptional regulators. International Journal of Obesity and Related Metabolic Disorders 20(Suppl 3),S52-7. 

Harata N, Iwasaki Y (1995) Evidence for early blood-brain btirrier breakdown in experimental thiamine deficiency in the mouse. Metab Brain Dis 10(2) 159-174 Harper CG (1983) The incidence of Wernicke s encephalopathy in Australia A neuropathological study of 131 cases. J Neurol Neurosurg Psychiatry 46 593-598 Harper CG, Butterworth RF (1997) Nutritional and metabolic disorders. In Graham DI, Lantos PL (eds) Greenfield s neuropathology. Arnold, London, pp 601-655 Hayton SM, Kriss T, Wase A, Muller DP (2006) Effects on neural function of repleting vitamin E-deflcient rats with alpha-tocopherol. J Neurophysiol 95(4) 2553-2559 Hayton SM, MuUer DP (2004) Vitamin E in neural and visual function. Ann N Y Acad Sd 1031 263-270... 

Ubbink JB (1997) The role of vitamins in the pathogenesis and treatment of hyperho-mocyst(e)inaemia. Journal of Inherited Metabolic Disorders 20,316-25. 

Another metabolic disorder that is hereditary and little known is hypophosphatasia. Hypophosphatasia is an inherited metabolic (chemical) bone disease that results from low levels of an enzyme called alkaline phosphatase (ALP). ALP is normally present in large amounts in bones and the liver. In hypophosphatasia, abnormalities in the gene that makes ALP lead to the production of inactive ALP. Subsequently, several chemicals, including phosphoethanolamine, pyridoxal 57-phosphate (a form of vitamin B ) and inorganic pyrophosphate, accumulate in the body and are found in large amounts in the blood and urine. It appears that the accumulation of inorganic pyrophosphate is the cause of the characteristic defective calcification of bones seen in infants and children (rickets) and in adults (osteomalacia). 

Metabolic disorders such as hypoglycemia, adrenal disease, vitamin deficiencies, electrolyte imbalances Organ diseases such as hepatic encephalopathy Pernicious anemia... 

In this section, I list diseases and conditions known to cause or accompany magnesium deficiency. My purpose is to show you that one disease can cause others by creating deficiencies that open up a person to other diseases.The following conditions are known to contribute to magnesium deficiency Bartter s syndrome bile insufficiency celiac disease bowel infections vomiting diarrhea alcoholism diabetes high levels of diuretics, vitamin D, or zinc hyperthyroidism metabolic disorders hormone disorders fat metabolism problems colostomy and kidney dysfunctions. 

These disorders can be thought of as relative vitamin deficiency states. Not all patients will respond to vitamins owing to the existence of pheno-copies. Data from L. E. Rosenberg Vitamin-responsive inherited metabolic disorders. In Advances in Human Genetics, Vol. 6, H. Harris and K. Hirschhom, Eds. (Plenum Press, 1976) and S. H. Mudd Vitamin-responsive genetic abnormalities. In Advances in Nutritional Research, Vol. 4 (Plenum Press, 1982). 

A multiphcity of metabolic disorders in patients with CKD contributes to worsening sHPT and the consequences associated with elevated PTH (Fig. 44-4). The continuous production of PTH by the parathyroid glands leads to parathyroid hyperplasia (nodular or diffuse). Nodular tissue demonstrates more rapid growth potential and appears to be associated with fewer vitamin D and calcium-sensing receptors, which results in resistance to the effects of calcium and vitamin D therapy and subsequent development of ROD. Bone loss can be detected in patients with early stages of kidney disease and multiple types of bone lesions have been identified from bone biopsies of patients on dialysis. The skeletal complications associated with ROD... 

One patient has been found with this deficiency (All). Hie patient, an infant, was mentally retarded, had a megaloblastic anemia and abnormally high levels of serum and erythrocyte folate. In spite of the high serum folate concentration there was a marked rise in the reticulocyte count when the patient was treated with folate. It was thought that the patient had impaired utilization of -methyltetrahydrofolate. Assay of liver W -methyltetrahy-drofolate transferase showed it to be reduced. It was suggested that folate accumulated at the N -methyltetrahydrofolate block and could therefore not be further utilized. Treatment with pteroylglutamic acid provided a means of producing active folate up to the point of the block. Unfortunately this patient was also treated with pyridoxine, and it is not clear which vitamin was responsible for the reticulocyte response. Further studies are required to determine the precise nature of this metabolic disorder. 

Single electron transfer generates radicals and although this mechanism is now more common than once thought in non-biological redox reactions, its prevalence in enzyme-catalysed reactions is limited to coenzymes with quinoid-type structures e.g. flavins, coenzyme Q, vitamins C, E and K and to enzymes containing transition metals. Of course, there is a growing interest in metabolic disorders initiated by radical reactions. Reduction by 2-electron transfer can take place by either (a) hydride, H, transfer or (b) discrete electron, e , and proton, H", addition. 

Among the difficulties caused by prolonged fasting are metabolic disorders caused by vitamin deficiencies. What vitamins are needed during starvation to ensure that cells can continue to carry out the metabolic adaptations discussed in Section 30.3.1 of the text ... 

In the investigation of vitamin deficiencies, it is well to bear in mind that diets deficient in a rangle vitamin produce metabolic disorders which alter the animal s requirement for other nutritional factors. Where pantothenic acid deficiency is concerned, there is evidence that the metabolism of ascorbic acid, biotin, protein, carbohydrate, and fat are involved. 

On the other hand, organic acids are more difficult to measure in the labs. Usually, these are measured by GC or HPLC. However, CE offers speed, precision, and specificity over other methods. Organic acids are important in inborn errors of metabolism, in infection, and different metabolic disorders. Many of these compounds have been measured by CE directly, or by indirect UV absorbency after addition of a UV absorbing compound such as benzoate, naphthalene sulfonate, imidazole, or benzylamine. For example, oxalate and citrate, which are important in stone formation, have been measured after urine dilution by both direct and indirect detections. Lactate, pyruvate, ascorbate, and oxalate were measured by CE in the CSF of patients in 10 min. Methylmalonic acid, which is a sensitive measure of vitamin Bi2 deficiency preceding any clinical symptoms or changes in the serum, has been determined in m-ine by CE after sample extraction and concentration. 

Our findings (Koyama el al. 1996,1997) that the smokers undergoing dialysis have peripheral neuropathy and that the fraction ratio of cyanocobalamin is comparable to that observed in patients with Leber s disease indicate the possibility of cyanide metabolism disorder in patients with CKD. In patients with CKD, thiocyanate (SCN) accumulates due to the decrease in its clearance. It impairs the major metabolic pathway of cyanide and the cyanide pool therefore increases. This increase accelerates cyanide detoxication via cyanocobalamin synthesis using vitamin B12, resulting in an increase in the... 

There have been several recent meta-analyses investigating the association of vitamin D status with cardio-metabolic disorders (hypertension, diabetes mellitus, dys-lipidemia) and morbidity/mortality related to CVD. Most of the meta-analyses have pooled together cross-sectional and prospective studies and evaluated disorders or CVD events between high and low 25(OH)D concentrations. The inclusion criteria vary for the published meta-analyses, thus indirectly commenting on the quality and heterogeneity of the studies published in the area (Pittas et al. 2010, Sokol et al. 2011). 

Vascular calcification is a process that involves accumulation of calcium deposits in vessel walls, resulting in increased arterial wall stiffness. Extra-osseous calcification occurs in areas of chronic inflammation, as in atherosclerotic lesions, in which oxidized lipids are the inflammatory stimulus. However, nonatherosclerotic calcification can occur in metabolic disorders like end-stage renal disease, diabetes, hyperparathyroidism, and vitamin K deficiency. This involves a complex interplay of various factors such as serum calcium and phosphate levels, activity of calcification promoters and inhibitors. Vascular calcification is associated with increased morbidity and mortality, predominantly from cardiovascular causes. ... 

With this one exception (the action of vitamin B12. in cyanide poisoning) the only certain chemotherapeutic action of vitamin B12 seems to be to correct the metabolic disorder which results from an existing deficiency of the vitamin. The effects, in terms of clinical improvement in pernicious anemia, for example, are remarkable, and much has been learned about the chemotherapeutic action of vitamin B12 by studying this disease. In other blood diseases—even in disorders so closely allied that the marrow is megaloblastic—vitamin B12 is without effect unless the disorder is due to lack of the vitamin. The same holds for diseases of the nervous system. The striking effect of vitamin B12 in subacute combined degeneration should not arouse false hopes that Bi2 will prove effective in cerebral, spinal, or neural disorders not due to deficiency of vitamin Bi2. 

There are 11 trace elements present in hormones, vitamins, enzymes and other proteins which have distinct biological roles. A deficiency in the trace elements results in metabolic disorders that are primarily associated with the absence or decreased activity of metabolic enzymes. 

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