B vitamins are a group of water-soluble vitamins that play important roles in cell metabolism.

The B vitamins were once thought to be a single vitamin, referred to as vitamin B (much as people refer to vitamin C). Later research showed that they are chemically distinct vitamins that often coexist in the same foods. In general, supplements containing all eight are referred to as a vitamin B complex. Individual B vitamin supplements are referred to by the specific name of each vitamin (e.g., B1, B2, B3 etc.).

The B vitamins are necessary to:
  • Support and increase the rate of metabolism
  • Maintain healthy skin, hair and muscle tone
  • Enhance immune and nervous system function
  • Promote cell growth and division, including that of the red blood cells that help prevent anemia
  • Reduce the risk of pancreatic cancer - one of the most lethal forms of cancer

All B vitamins are water-soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished regularly to avoid sickness and death from the specific deficiency disease.

B vitamins have also been hypothesized to reduce the symptoms of attention deficit hyperactivity disorder.

B vitamin deficiency

Several named vitamin deficiency diseases may result from the lack of sufficient B-vitamins. Deficiencies of other B vitamins result in symptoms that are not part of a named deficiency disease.

Vitamin Name Deficiency effects'

Vitamin B1 thiamine Deficiency causes beriberi. Symptoms of this disease of the nervous system include weight loss, emotional disturbances, Wernicke's encephalopathy (impaired sensory perception), weakness and pain in the limbs, periods of irregular heartbeat, and edema (swelling of bodily tissues). Heart failure and death may occur in advanced cases. Chronic thiamine deficiency can also cause Korsakoff's syndrome, an irreversible psychosis characterized by amnesia and confabulation.

Vitamin B2 riboflavin Deficiency causes ariboflavinosis. Symptoms may include cheilosis (cracks in the lips), high sensitivity to sunlight, angular cheilitis, glossitis (inflammation of the tongue), seborrheic dermatitis or pseudo-syphilis (particularly affecting the scrotum or labia majora and the mouth), pharyngitis (sore throat), hyperemia, and edema of the pharyngeal and oral mucosa.

Vitamin B3 niacin Deficiency, along with a deficiency of tryptophan causes pellagra. Symptoms include aggression, dermatitis, insomnia, weakness, mental confusion, and diarrhea. In advanced cases, pellagra may lead to dementia and death (the 3(+1) Ds: dermatitis, diarrhea, dementia, and death).

Vitamin B5 pantothenic acid Deficiency can result in acne and paresthesia, although it is uncommon.

Vitamin B6 pyridoxine Deficiency may lead to microcytic anemia (because pyridoxyl phosphate is the cofactor for heme synthesis), depression, dermatitis, high blood pressure (hypertension), water retention, and elevated levels of homocysteine.

Vitamin B7 biotin Deficiency does not typically cause symptoms in adults but may lead to impaired growth and neurological disorders in infants. Multiple carboxylase deficiency, an inborn error of metabolism, can lead to biotin deficiency even when dietary biotin intake is normal.

Vitamin B9 folic acid Deficiency results in a macrocytic anemia, and elevated levels of homocysteine. Deficiency in pregnant women can lead to birth defects. Supplementation is often recommended during pregnancy. Researchers have shown that folic acid might also slow the insidious effects of age on the brain.

Vitamin B12 cobalamin Deficiency results in a macrocytic anemia, elevated homocysteine, peripheral neuropathy, memory loss and other cognitive deficits. It is most likely to occur among elderly people, as absorption through the gut declines with age; the autoimmune disease pernicious anemia is another common cause. It can also cause symptoms of mania and psychosis. In rare extreme cases, paralysis can result.

B3- Niacin is a water-soluble vitamin, which is also known as nicotinic acid or vitamin B3. Nicotinamide is the derivative of niacin and used by the body to form the coenzymes nicotinamide adenine dinucleotide (NAD) and nicotinamide adenine dinucleotide phosphate (NADP). None of the forms are related to the nicotine found in tobacco, although their names are similar. One recommended daily allowance of niacin is 2.12 mg/day for children, 14 mg/day for women, 16 mg/day for men, and 18 mg/day for pregnant or breast-feeding women.



Ref: ^ "B Vitamins". U.S. National Library of Medicine. Retrieved 11 August 2012.

. ^ "Pellagra". U.S. National Library of Medicine. Retrieved 11 August 2012.

. ^ "Beriberi". U.S. National Library of Medicine. Retrieved 11 August 2012.

. ^ Office of Dietary Supplements. "Dietary Supplement Fact Sheet:Vitamin B6". National Institutes of Health. Retrieved 11 August 2012.

. ^ "Vitamin B6". U.S. National Library of Medicine. Retrieved 11 August 2012.

. ^ "Confronting Pancreatic Cancer". Archived from the original on 3 February 2008. Retrieved 2008-02-08.

. ^ Schernhammer, E., et al. (June 1, 2007). "Plasma Folate, Vitamin B6, Vitamin B12, and Homocysteine and Pancreatic Cancer Risk in Four Large Cohorts". Cancer Research 67 (11): 5553.60. doi:10.1158/0008-5472.CAN-06-4463. PMID 17545639. Retrieved 2008-02-08.

. ^ United Press International (June 1, 2007). "Pancreatic cancer risk cut by B6, B12". Archived from the original on 10 March 2008. Retrieved 2008-02-08.

. ^ Vitamins, water soluble at

^ Shaw I, Rucklidge JJ, Hughes RN. (2010). "A Possible Biological Mechanism for the B Vitamins Altering Behaviour in Attention-Deficit/Hyperactivity Disorder". Pharm Med 24 (5): 289.294. doi:10.2165/11584440-000000000-00000.

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