Monday, October 5, 2009

The important Vitamin B12

Functions
They observed three main enzymatic reactions regarding vitamin B12 can occur in humans. The first reaction requires methylcobalamin as a coenzyme in the conversion of homocysteine to methionine. This reaction in the cell cytosol.
The reaction is necessary for the production of tetrahydrofolate (THF). The production of THF is irreversible and requires vitamin B12 vitamin B12, in the event of the form of methyl folic acid (also called folate methyl trap), which in turn affects purine and thymidylate synthesis.

A second set of actions requiring mutase catalysed B12. These reactions occur in mitochondria. These include the production of succinyl-CoA, an intermediate in the cycle of Krebs. Mutase Enzymes are also a factor in the oxidation of fatty acids. An error in the results of mutase activity impai.red muscle activity and the accumulation of methylmalonyl CoA and methylmalonic acid. The branched-chain amino acid leucine is catalyzed by an enzyme mutase. In particular, leucine isomerization occur, requiring adenosylcobalamin.

Sources
The only dietary sources of vitamin B12 are animal products. Plants and legumes are good sources of vitamin B12, but only small amounts of vitamin B12, including contamination by microorganisms during harvesting. Cobalamins in meat, meat, poultry, fish, mussels, oysters and eggs. The bioavailability of cobalamins depends on what shape are in.

Two micrograms daily, the recommended daily intake of vitamin B12. Doses of vitamin C, which can not exceed 500 mg was added, and I hour after eating a meal with reduced B12 absorption;

Deficiency symptoms
Over 95% of vitamin B12 have been diagnosed with deficiencies in absorption rather than inadequate food intake in this context. The vitamin B12 occurs in different stages of development that are within the blood cells and key. The vitamin B12 later (results megaloblastic anemia can also be caused by a deficiency of folic acid, so it is) better treatment with a combination of vitamin B12 and folic acid.
Signs of vitamin B12 progressive neuropathy characterized by demyelination of nerve and hyperhomocystinemia. Population at highest risk for vitamin B12 do not understand that the athletes but the elderly, alcoholics, patients with gastrectomy and strict vegetarians (vegans).

Human Studies
Known in the late I980s Dibencozide a popular dietary supplement as a coenzyme of vitamin B12) (assumed to have properties similar to steroids. It was crucial and has not been confirmed by research. Bodybuilders are known to use cyanocobalamin injection as an appetite stimulant and increase of muscle mass. That was the role of vitamin B12 misunderstood the red blood cells and protein synthesis. To date, no serious study to demonstrate the performance-enhancing effect of vitamin B12 or any of the forms of cobalamin.


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