Vitamin B1 (Thiamin):
· They are considered extremely important for the breakdown of carbohydrates into energy.
· Thiamin is involved in the transmission of high frequency impulses across nerve synapses, the junctions between neighboring nerve cells, across which signals are carried by chemical neurotransmitters.
· Thiamine is also known to be involved in the conversion of amino acid tryptophan to the vitamin niacin and the metabolism of the branched chain amino acids leucine, isoleucine, and valine.
SOURCES: Diet based on whole wheat, any of the millets, raw hand pounded rice or parboiled rice usually supplies adequate amounts of thiamin. Organ meat, pork, liver, and egg also supply thiamine.
Vitamin B2 (Riboflavin):
Like thiamine, riboflavin serves as a coenzyme in several enzyme systems of the body that is involved in the metabolism of energy nutrients.
SOURCES: Good sources of riboflavin are milk and milk products including skimmed milk, buttermilk, curd, cheese, whey, egg, liver, and green vegetables. Polished rice and other refined cereals contain very little riboflavin.
· Niacin is required by all cells. Like thiamine and riboflavin, it plays a vital role in the release of energy from all the energy-yielding nutrients – carbohydrate, fat, protein, and alcohol.
· It is also required for the synthesis of protein, fat, and five-carbon sugars (pentoses) needed for the formation of DNA and RNA.
SOURCES: Whole cereals, pulses, nuts, and meat are good sources of niacin. Groundnut is particularly rich in nicotinic acid.
Vitamin B6 functions as part of coenzyme systems in the body that aid in the metabolism of amino acid, fatty acids, and the release of energy. It occurs in tissues predominantly as pyridoxal or pyridoxamine phosphate. Pyridoxal phosphate functions in a number of reactions that are essential in the metabolism of amino acids: decarboxylation (removal of CO2 group), transamination (transfer of NH2 group), and desulfuration (removal of H2S group). The conversion of niacin, depends on the action of this coenzyme.
SOURCES: Meat, pulses and wheat are known to be rich sources while other cereals are fair sources of the vitamin. Fruits and vegetables are poor sources.
Vitamin B12 functions as a coenzyme in the metabolism of body cells, particularly for cells of the bone marrow, the nervous system, and gastrointestinal tract.
SOURCES: Animal proteins are the chief source of vitamin B12 in the food intake milk, fish, poultry are considered good sources whereas grains vegetables and legumes are poor carriers of the vitamin.
Folate is now known to be required for normal growth and division of all cells.
The specific biochemical the function of folate is to act as a coenzyme in reactions involving the transfer of one carbon unit such as the methyl group from one metabolite to another. Examples of processes requiring the presence of folate are the following:
· Along with vitamin B12 folic acid helps in the transmethylation of homocysteine to methionine, ethanolamine to choline and uracil to thymine.
· The conversion of amino acid phenylalanine into the amino acid tyrosine.
· The formation of the heme group of hemoglobin.
· The synthesis of the purine and pyrimidine bases needed for the synthesis of deoxyribonucleic acid (DNA) and ribonucleic acid (RNA).
· The formation of the vitamin-like compound choline from ethanolamine.
· The conversion of the vitamin niacin to N-methyl nicotinamide, the form in which it is excreted.
· Folic acid required for the normal metabolic pathway of histidine, particularly in the conversion of formimino glumatic acid to glumatic acid.
SOURCES: Folic acid is present in both animal and plant foods. Fresh green vegetables, liver, pulses are good sources of this vitamin.
Panthothenic acid functions in the body as a part of the coenzyme called coenzyme A. This coenzyme mediates acetylation, the transfer or acceptance of the acetyl group. Coenzyme A is one of the enzymes involved in the series of chemical reactions that are necessary to break down carbohydrates and fats for the production of energy.
SOURCES: The best sources of pantothenic acid are liver, kidney, egg yolk, yeast, fresh vegetables. Milk and meat are fairly good sources.