Vitamin Bs deficiency

Rat Manure-fertilized seed versus chemically fertilised seed Greater weight gain in vitamin B-deficient rats fed manure-fertilised seed (Rowlands and Wilkinson, 1930)... 

ALA synthase, the rate-limiting enzyme, requires pyridoxine (vitamin B ). Deficiency of pyri-doxine is associated with isoniazid therapy for tuberculosis and may cause sideroblastic anemia with ringed sideroblasts. 

Ihble 1-17-6. Comparison of Vitamin B. Deficiency, Iron Deficiency, and Lead Poisoniiig... 

Of 50 adult rats used in a reproductive/developmental study, 22% of those that received 6 mg/kg/day heptachlor in the diet developed lens cataracts 4.5-9.5 months following exposure. In addition, 6-8% of the pi offspring and 6% of the p2 offspring of these rats also developed cataracts 19-21 days after birth (Mestitzova 1967). The author of this study eliminated the possibility of a vitamin B deficiency or a recessive genetic trait as the cause of the cataracts. She could not rule out the possibility of altered vitamin B metabolism caused by heptachlor. 

Cataracts (Mestitzova 1967) and decreased postnatal survival (Green 1970) were reported in the progeny of rats fed diets containing heptachlor in intermediate- and chronic-duration studies. Data were insufficient to further evaluate these studies. Although the authors did not offer a mechanism, they did rule out vitamin B deficiency in the development of the cataracts. Because cataracts have... 

Vitamin B deficiency is a rare condition, but it is prevalent in persons with chronic alcoholism due to low dietary Intake and impaired conversion ofpyridoxine to the active coenzyme pyridoxal phosphate. 

Historically choline, inositol and carnitine have been considered to be part of the vitamin B complex. However, for the general population there has been no demonstration of a dietary need for these agents and also for none of them has there been a therapeutic role established. Vitamins of the B family are found in many food ingredients like in yeast, in meat, in dairy products and also in eggs and grain cereals and separate vitamin B deficiencies are unlikely to occur. Excessive intake of these vitamins is eliminated in the urine because of the fact that they are water-soluble. 

Pyridoxine is indicated in vitamin B deficiency, for the treatment of some pyridoxine responsive anemia s and for isoniazid-induced neuropathy. It may relieve symptoms of pellagra when niacin fails. Long-term administration of large doses may produce neurotoxicity manifesting itself in progressive peripheral sensory neuropathy. 

Deficiency symptoms In severe vitamin B deficiency beriberi develops. 

Bioavailability of Niacin. Factors which cause a decrease in macm availability include (1) Cooking losses (2) bound form in corn (maize), greens, and seeds is only partially available (3) presence of oral antibiotics (4) diseases which may cause decreased absorption (5) decrease in tiyptophan conveision as in a vitamin B deficiency. Fac.tois that increase availability include (1) alkali treatment of cereals (2) storage in bver and possibly in muscle and kidney tissue and (3) increased intestinal synthesis. 

Increased skin pigmentation may occur, especially in dark-skinned women. It tends to increase with time, the incidence being about 5% at the end of the first year and about 40% after 8 years. It is thought to be exacerbated by vitamin B deficiency. It is often reversible upon discontinuance of medication but may disappear very slowly. 

Figure 7. Comparative stimulation of glutamic acid, alanine, and proline accumulation in vitamin B -deficient cells of L. arabinosus at various extracellular sucrose concentrations...

Generalized malnntrition may prodnce conjunctival kera-tinization. Vitamin B deficiency can canse abnormal dilatation of the conjnnctival vasculatnre. Vitamin C deficiency can prodnce petechial or spontaneous subconjunctival hemorrhages. Avitaminosis A can cause severe drying of the ocular surfece and the appearance of Bitot s spots on the temporal conjunctiva. 

D ll) Vitamin B, deficiency. By reducing pyri-doxal phosphate availability at the entrance to Porphy s Hemeland, an anemia may result through decreased ability to form heme. 

Vitamin B] deficiency is commonly caused by pernicious anemia (PA). TA is an autoimmune disease resulting from the body s production of antibodies that recognize inlrinsic factor or other proteins of the parietal cell. The binding of antibodies to these proteins results in loss of their function. The parietal cells may be destroyed and be undetectable in patients with PA. The major defect in PA is gastric atrophy. 1 here may be a lack of all gastric secretions, including intrinsic factor, gastric acid, and pepsin. 

Biochemi iy of Vitamin 8 2 Vtemin Bjj Deficiency Causes of Vitamin B Deficiency Assessment of Vtamin B Status Vitamin K... 

Brattsrom, L., Israelsson, B., Lindgarde, F., and Hultberg, B. (1988). Higher total plasma homocyteine in vitamin B deficiency than in heterozygosity for homocyteinuria due to cystathione P-synthase deficiency. Metabolism 37,175-178. 

Higginbottom, M. C., Sweetman, L., and Nyhan, W. L. (1978). A S5mdrome of methylmalonic aciduria, homocysteinuria, megaloblastic anemia, and neurological abnormalities in a vitamin B -deficient breast-fed infant of a strict vegetarian. N. Engl. J. Med. 299, 317-323. 

The only official indication for pantothenic acid is in the prevention or treatment of vitamin B deficiencies. Bccau.se a deficiency of a single B vitamin is rare, it is commonly formulated in multivitamin preparations or B-complex preparations. 

Because of inadequate diets, some infants suffer from severe vitamin B deficiencies that can lead to cpilepsy-like convulsive seizures, and the convulsions can be controlled by treatment with pyridoxine. The convulsions are believed to be due to below-normal availability of the central nervous... 

A review by Rase . summarizes. studies on the effects of certain hormones on vitamin B(, nutrition in humans, on the biochemical interrelationship between steroid hormones and pyridoxal phasphate-dependent enzymes, and on the role of vitamin B(, in regulating hypothalamus-pituitary functions. Some of these studies have important clinical implications. The use of estrogen-containing oral contraceptives has been investigated as a factor leading to an abnormality of tiyptophan metaboli.sm. This abnormality resembles dietary vitamin B deficiency and responds favorably to treatment with the vitamin. For some time, there has been clinical interest in the relationship between certain hormones and vitamin B function because abnormal urinary excretion of tiyptophan metabolites was observed during pregnancy and in patients with hyperthyroidism. 

The measurement of holotranscobalamin II is potentially useftil as a specific marker of biologically available vitamin Bi2, because only cobalamin bound to Tell is specifically available for uptake by aU cells. Other methods have been described for the measurement of holotranscobalamin in serum, one using an immobilized monoclonal antibody to human transcobalamin, followed by measurement of released cobalamin by CPB, This method is currently available as a commercial kit. The other method uses magnetic beads coated with cobalamin to precipitate apotranscobalamin followed by measurement of the holotranscobalamin in the supernatant by ELISA. Though these methods are claimed to be precise and simple to perform, there remains doubt over the interpretation of the measured concentrations, and over their sensitivity and specificity in the diagnosis of vitamin B deficiency. ... 

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