Vitamin B6 vs Vitamin B12
Vitamins are vital nutrients essential for the normal functioning of different enzymes and metabolic pathways of the body. All vitamins are needed for specific functions and most are obtained from food. Vitamins can be classified into water soluble and fat soluble types. B vitamins are essentially water soluble vitamins with different subcategories based on their chemical structure.
Vitamin B6 and Vitamin B12 are vitamins which are similar in function also to a certain extent. About 100 enzymes involved in protein metabolism require Vitamin B6 for normal functioning. Pyridoxine, pyridoxamine and pyridoxal are the three forms of vitamin B6.
Vitamin B12 is also water soluble having different forms such as Methylcobalamin and 5-deoxyadenosylcobalamin. These two forms take part in human metabolism. Vitamin B12 requires the cofactor cobalt and hence generally called as ‘cobalamines’.
Vitamin B6 is an essential factor in RBC metabolism and efficient functioning of immune and nervous systems. The vitamin is easily available in fortified cereals, meat, fish, poultry, fruits and vegetables. Tryptophan is converted to niacin by Vitamin B6.
Vitamin B6 has some of the major functions such as maintaining your blood glucose and to produce haemoglobin. In fasting, when the caloric levels go down, the body synthesizes glucose from other carbohydrates using Vitamin B6. It is also essential for efficient immune response and antibody production.
Vitamin B6 deficiency may cause dermatitis, glossitis, confusion, depression and convulsions. Sometimes it can cause anemic conditions also. These symptoms are more general and hence cannot be attributed to the deficiency of vitamn B6 alone. Also the symptoms appear at a later stage after chronic lack of nutrients.
The upper tolerable level for adults have been found as 100 mg per day and once the dosage crosses this limit, the body typically shows adverse effects. Too much of the vitamin can also cause neuropathy.
Vitamin B12 is a water soluble vitamin found in animal products in bound form and is freed on action of hydrochloric acid and gastric protease. The vitamin is required for the formation of red blood corpuscles, DNA synthesis and function of nervous tissue. The deficiency results in a serious type of anaemia called pernicious anaemia which occurs in elder people. The use of vitamin B12 in other conditions such as aging, immune system functioning, memory loss etc requires further evidence to prove the effects. Contraindications have been noted with intake of other vitamins, especially vitamin C.
Pernicious anaemia if left untreated results in an irreversible megaloblastic anaemia and disorders of the nervous system. The vitamin is involved in the formation of methyl malonyl CoA, and hence the molecule is an effective indicator for the level of vitamin B12.
The ability of absorption of vitamin B12 from diet varies according to the individual’s make up. Oral and sublingual supplements are available. A vegetarian food does not provide adequate amounts of vitamin B12 and thus may need supplements. It is also important for myelin synthesis and repair.
1. Both vitamin B6 and vitamin B12 are involved in conversion of homocysteine to methionine.
2. Vitamin B12 requires a transcobalamin molecule to transport the vitamin to the tissues whereas vitamin B6 does not require any specific transporter.
3. The absorption of Vitamin B12 is mediated by an intrinsic factor.
4. The food bound vitamin B12 is bound to haptocorrin (R-protein) which requires action of pancreatic enzymes to be cleaved and released.
5. The effects of deficiency are more pronounced in vitamin B12 compared to vitamin B6. The primary causes of deficiency of vitamin B12 includes vegan diet, impaired absorption and inadequate utilization etc
6. The usual source of vitamin B6 is fruits and vegetables and a vegan diet does not hamper the adequacy of the vitamin in the diet. Vitamin B12 levels reduce significantly over a vegan diet.
7. Dietary deficiency is rare with vitamin B6 although serious and chronic shortage can cause disease Pellagra.
8. Both vitamins are effective in decreasing the level of homo-cysteine in blood.
9. The deficiency of both vitamins can affect the neurological functions.
The vitamins B6 and B12 are required for the nucleic acid metabolism, lipid metabolism etc. Both reduce the homo cysteine levels in blood and are supplemented through diet. Vitamin B12 requires a metal ion of cobalt to act as cofactor for nomal functioning.
The effects of deficiency are more pronounced in vitamin B12 compared to vitamin B6. Primary deficiency is almost a rarity in case of vitamin B6. Over dosage can occur rarely. Vitamin B12 is stored in human body whereas Vitamin B6 is excreted on a regular basis. The ideal diet should contain a balanced intake of both vitamins. Usually doctors prescribe a multivitamin supplement, including folate in addition to vitamins B6 and B12 and it is found to be effective for most of the problems related to the vitamin deficiency.