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 or vitamin D). 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:
All B vitamins are water-soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished regularly, since any excess is excreted in the urine.[4] This can result in the urine produced being a neon green-yellow colour.
B vitamins have also been hypothesized to reduce the symptoms of attention deficit hyperactivity disorder.[5]
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. |
Although most B vitamins are eliminated regularly in the urine, taking large doses of certain B vitamins may produce harmful effects.
| Vitamin |
Name |
Tolerable Upper Intake Level |
Harmful effects |
| Vitamin B1 |
thiamine |
None[6] |
No known toxicity from oral intake. There are some reports of anaphylaxis caused by high-dose thiamin injections into the vein or muscle. However, the doses were greater than the quantity humans can physically absorb from oral intake.[6] |
| Vitamin B2 |
riboflavin |
None.[7] |
No evidence of toxicity based on limited human and animal studies. The only evidence of adverse effects associated with riboflavin comes from in vitro studies showing the production of reactive oxygen species (free radicals) when riboflavin was exposed to intense visible and UV light.[7] |
| Vitamin B3 |
niacin |
35 mg/day from supplements, drugs or fortified food[8] |
Intake of 3000 mg/day of nicotinamide and 1500 mg/day of nicotinic acid are associated with nausea, vomiting, and signs and symptoms of liver toxicity. Other effects may include glucose intolerance, and (reversible) ocular effects. Additionally, the nicotinic acid form may cause vasodilatory effects, also known as flushing, including redness of the skin, often accompanied by an itching, tingling, or mild burning sensation, which is also often accompanied by pruritus, headaches, and increased intracranial blood flow, and occasionally accompanied by pain.[8] Medical practitioners prescribe recommended doses up to 2000 mg. per day of niacin, usually in time release format, to combat arterial plaque development in cases of high lipid levels.[9] |
| Vitamin B5 |
pantothenic acid |
None |
No known toxicity |
| Vitamin B6 |
pyridoxine |
100 mg/day from supplements, drugs or fortified food[10] |
Intake of more than 1000 mg/day is associated with peripheral sensory neuropathy; other effects are unconfirmed: dermatological lesions [causal association is unlikely]; B6 dependency in newborns [causal association is also unlikely].[10] |
| Vitamin B7 |
biotin |
None |
No known toxicity |
| Vitamin B9 |
folic acid |
1 mg/day [11] |
Masks B12 deficiency, which can lead to permanent neurological damage[11] |
| Vitamin B12 |
cyanocobalamin |
None established.[12] |
Acne-like rash [causality is not conclusively established].[12][13] |
B vitamins are found in whole unprocessed foods. Processed carbohydrates such as sugar and white flour tend to have lower B vitamin than their unprocessed counterparts. B vitamins are particularly concentrated in meat such as turkey and tuna, in liver and meat products.[14] Good sources for B vitamins include kombucha, whole grains, potatoes, bananas, lentils, chili peppers, tempeh, beans, nutritional yeast, brewer's yeast, and molasses. Although the yeast used to make beer results in beers being a source of B vitamins,[15] their bioavailability ranges from poor to negative as drinking ethanol inhibits absorption of thiamine (B1),[16][17] riboflavin (B2),[18] niacin (B3),[19] biotin (B7),[20] and folic acid (B9).[21][22] In addition, each of the preceding studies further emphasizes that elevated consumption of beer and other ethanol-based drinks results in a net deficit of those B vitamins and the health risks associated with such deficiencies.
The B12 vitamin is of note because it is not available from plant products, making B12 deficiency a concern for vegans. Manufacturers of plant-based foods will sometimes report B12 content, leading to confusion about what sources yield B12. The confusion arises because the standard US Pharmacopeia (USP) method for measuring the B12 content does not measure the B12 directly. Instead, it measures a bacterial response to the food. Chemical variants of the B12 vitamin found in plant sources are active for bacteria, but cannot be used by the human body. This same phenomenon can cause significant over-reporting of B12 content in other types of foods as well.[23]
Vitamin B may also be delivered by injection to reverse deficiencies.[24]
Another popular means of increasing one's vitamin B intake is through the use of dietary supplements. B vitamins are also commonly added to energy drinks, many of which have been marketed with large amounts of B vitamins[25] with claims that this will cause the consumer to "sail through your day without feeling jittery or tense."[25] Nutritionists, such as Case Western University Professor Hope Barkoukis, dismiss these claims: "It's brilliant marketing, but it doesn't have any basis [in fact]."[25]
While B vitamins do "help unlock the energy in foods," just about everyone in America already gets all of the B vitamins they could possibly need in their diets.[citation needed] In general, extra B vitamins are just flushed out of the system, although everyone's limit of absorption is different in regards to B complex vitamins, and no one knows how much is needed on an individual basis of these vitamins…"[25] The elderly and athletes may need to supplement their intake of B12 and other B vitamins due to problems in absorption and increased needs for energy production. Both type 1 and type 2 diabetics may also be advised to supplement thiamine based on high prevalence of low plasma thiamine concentration and increased thiamine clearance associated with diabetes.[26] Also, Vitamin B9 (folic acid) deficiency in early embryo development has been linked to neural tube defects. Thus, women planning to become pregnant are usually encouraged to increase daily dietary folic acid intake and/or take a supplement.[27] However, for "most typical consumers of energy supplements or drinks, B vitamins are nothing more than a 'gimmick'."[25]
Many of the following substances have been referred to as vitamins because they were believed to be vitamins at one time. They are not considered vitamins anymore and the numbers that were assigned to them now form the "gaps" in the true series of B-complex vitamins described above (e.g. there is no vitamin B4). Some of them, though not essential to humans, are essential in the diets of other organisms; others have no known nutritional value and may even be toxic under certain conditions.
- Vitamin B7: is also known as "vitamin I" of Centanni E. (1935)—also called "Enteral factor"—is a water and alcohol-soluble rice-bran factor that prevents digestive disturbance in pigeons. It governs the anatomical and functional integrity of the intestinal tract. Later found in yeast. Possible candidates for this substance are inositol, niacin (nicotinic acid), and biotin. Carnitine was also claimed to be a candidate but is not soluble in alcohol. Ref: Biochim, e terap. sper. 22:137 (April 30)1935 E. Centenni. Presse med. 51 No6 66-7 1943 R. Jacquot (on enteral B7 in Yeast) et al.
- Vitamin B8: adenosine monophosphate, or alternately myo-inositol, is synthesized by the human body.[citation needed]
- Vitamin B10: para-aminobenzoic acid (PABA)
- Vitamin B11: pteryl-hepta-glutamic acid—chick growth factor, which is a form of folic acid. Later found to be one of five folates necessary for humans; also known as vitamin S or factor S.
- Vitamin B13: orotic acid, now known not to be a vitamin.
- Vitamin B14: cell proliferant, anti-anemia, rat growth factor, and antitumor pterin phosphate named by Earl R. Norris. Isolated from human urine at 0.33ppm (later in blood), but later abandoned by him as further evidence did not confirm this. He also claimed this was not xanthopterin.
- Vitamin B15: pangamic acid
- Vitamin B16: dimethylglycine (DMG)
- Vitamin B17: nitrilosides, amygdalin or Laetrile. These substances are found in a number of seeds, sprouts, beans, tubers, and grains. While toxic in large quantities, proponents claim that it is effective in cancer treatment and prevention despite a lack of scientific evidence.[29]
- Vitamin B18:
- Vitamin B19:
- Vitamin B20: carnitine
- Vitamin B21:
- Vitamin B22: often claimed as an ingredient of Aloe vera extracts but also in many other foods. Claimed by one source to be vitamin B12b-δ.[citation needed]
- Vitamin Bh: biotin
- Vitamin Bm: "mouse factor": also used to designate inositol
- Vitamin Bp: choline[dubious – discuss] Choline is only required for survival of some mutants. Most commonly it is synthesized in vivo de novo.[30] May be added as supplement especially when methionine supply is limited[why?]
Note: B16, B17, B18, B19, B20, B21 & B22 do not appear to be animal factors but are claimed by some naturopaths as human therapeutic factors.[citation needed]
- ^ "Confronting Pancreatic Cancer". http://www.pancreatica.org. 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. http://cancerres.aacrjournals.org/cgi/content/abstract/67/11/5553. Retrieved 2008-02-08.
- ^ United Press International (June 1, 2007). "Pancreatic cancer risk cut by B6, B12". UPI.com. http://www.upi.com/Consumer_Health_Daily/Briefing/2007/06/01/pancreatic_cancer_risk_cut_by_b6_b12/3712/. Retrieved 2008-02-08.
- ^ Vitamins, water soluble at FAQ.org
- ^ 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. http://adisonline.com/pharmaceuticalmedicine/Fulltext/2010/24050/A_Possible_Biological_Mechanism_for_the_B_Vitamins.3.aspx.
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 4 - Thiamin". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 58–86. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/58-86_150.pdf. Retrieved 2009-06-17.
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 5 - Riboflavin". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 87–122. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/87-122_150.pdf. Retrieved 2009-06-17.
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 6 - Niacin". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 123–149. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/123-149_150.pdf. Retrieved 2009-06-17.
- ^ http://www.rxabbott.com/pdf/niaspan.pdf
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 7 - Vitamin B6". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 150–195. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/150-195_150.pdf. Retrieved 2009-06-17.
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 8 - Folate". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 196–305. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/196-305_150.pdf. Retrieved 2009-06-17.
- ^ a b National Academy of Sciences. Institute of Medicine. Food and Nutrition Board., ed. (1998). "Chapter 9 - Vitamin B12". Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline. Washington, D.C.: National Academy Press. pp. 346. ISBN 0-309-06411-2. http://www.nal.usda.gov/fnic/DRI//DRI_Thiamin/306-356_150.pdf. Retrieved 2010-09-23.
- ^ Dupré, A; Albarel, N; Bonafe, JL; Christol, B; Lassere, J (1979). "Vitamin B-12 induced acnes". Cutis; cutaneous medicine for the practitioner 24 (2): 210–1. PMID 157854.
- ^ Stipanuk, M.H. (2006). Biochemical, physiological, molecular aspects of human nutrition (2nd ed.). St Louis: Saunders Elsevier p.667
- ^ Winklera, C; B. Wirleitnera, K. Schroecksnadela, H. Schennachb and D. Fuchs (September 2005). "Beer down-regulates activated peripheral blood mononuclear cells in vitro". International Immunopharmacology 6 (3): 390–395. DOI:10.1016/j.intimp.2005.09.002. PMID 16428074. http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6W7N-4H6XNCT-1&_user=4423&_rdoc=1&_fmt=&_orig=search&_sort=d&_docanchor=&view=c&_searchStrId=1170050114&_rerunOrigin=scholar.google&_acct=C000059605&_version=1&_urlVersion=0&_userid=4423&md5=ad33efbb2638c397f63aa8c4e2b202af. Retrieved 2010-01-18.
- ^ Hoyumpa Jr, AM (1980). "Mechanisms of thiamin deficiency in chronic alcoholism". American Journal of Clinical Nutrition 33 (12): 2750–2761. PMID 6254354. http://www.ajcn.org/cgi/content/abstract/33/12/2750. Retrieved 2010-01-18.
- ^ Leevy, Carroll M. (1982). "Thiamin deficiency and alcoholism". Annals of the New York Academy of Sciences 378 (Thiamin: Twenty Years of Progress): 316–326. DOI:10.1111/j.1749-6632.1982.tb31206.x. http://www3.interscience.wiley.com/journal/119560210/abstract?CRETRY=1&SRETRY=0. Retrieved 2010-01-18.
- ^ Pinto, J; Y P Huang, and R S Rivlin (May 1987). "Mechanisms underlying the differential effects of ethanol on the bioavailability of riboflavin and flavin adenine dinucleotide". Journal of Clinical Investigation 79 (5): 1343–1348. DOI:10.1172/JCI112960. PMC 424383. PMID 3033022. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=424383.
- ^ Spivak, JL; DL Jackson (June 1977). "Pellagra: an analysis of 18 patients and a review of the literature". The Johns Hopkins Medical Journal 140 (6): 295–309. PMID 864902.
- ^ Said, HM; A Sharifian, A Bagherzadeh and D Mock (1990). "Chronic ethanol feeding and acute ethanol exposure in vitro: effect on intestinal transport of biotin". American Journal of Clinical Nutrition 52 (6): 1083–1086. PMID 2239786. http://www.ajcn.org/cgi/content/abstract/52/6/1083. Retrieved 2010-01-18.
- ^ Halsted, Charles; Picciano, M.F., Stokstad, E.L.R. and Gregory, J.F. (eds) (1990). Intestinal absorption of dietary folates (in Folic acid metabolism in health and disease). New York, New York: Wiley-Liss. pp. 23–45. ISBN 0-471-56744-2. http://agris.fao.org/agris-search/search/display.do?f=1992/v1803/US9141384.xml;US9141384.
- ^ Watson, Ronald; Watzl, Bernhard, eds. (September 1992). Nutrition and alcohol. CRC Press. pp. 16–18. ISBN 978-0-8493-7933-8.
- ^ Herbert, Victor (1 September 1998). "Vitamin B-12: Plant sources, requirements, and assay". Am. J. Clin. Nutr. 48 (3): 852–8. PMID 3046314. http://www.ajcn.org/cgi/reprint/48/3/852. Retrieved 2008-02-26.
- ^ Vitamin B injections mentioned
- ^ a b c d e Chris Woolston (July 14, 2008). "B vitamins don't boost energy drinks' power". Los Angeles Times. http://www.latimes.com/features/health/la-he-skeptic14-2008jul14,0,3939169.story. Retrieved 2008-10-08.
- ^ . DOI:10.1007/s00125-007-0771-410.1007/s00125-007-0771-4. PMC 1998885. PMID 17676306. //www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=1998885.
- ^ . DOI:10.1097/00001648-199505000-00005. PMID 7619926.
- ^ Vera Reader (1930). "The assay of vitamin B4". Biochem J. 24 (6): 1827–31.. PMC 1254803. PMID 16744538. http://www.biochemj.org/bj/024/1827/0241827.pdf.
- ^ Lerner IJ (February 1984). "The whys of cancer quackery". Cancer 53 (3 Suppl): 815–9. DOI:10.1002/1097-0142(19840201)53:3+<815::AID-CNCR2820531334>3.0.CO;2-U. PMID 6362828.
- ^ Stecol JA (1958). "Biosynthesis of Choline and Betaine". Am J Clin Nutr. 6 (3): 200–15.. PMID 13533306. http://www.ajcn.org/cgi/reprint/6/3/200.pdf.
|
|
|
| Fat soluble |
|
|
|
|
|
|
D2 ( Ergosterol, Ergocalciferol#) · D3 ( 7-Dehydrocholesterol, Previtamin D3, Cholecalciferol, 25-hydroxycholecalciferol, Calcitriol (1,25-dihydroxycholecalciferol), Calcitroic acid) · D4 ( Dihydroergocalciferol) · D5 · D analogues ( Alfacalcidol, Dihydrotachysterol, Calcipotriol, Tacalcitol, Paricalcitol)
|
|
|
|
|
|
|
|
|
|
|
| Water soluble |
|
B
|
B1 ( Thiamine#) · B2 ( Riboflavin#) · B3 ( Niacin, Nicotinamide#) · B5 ( Pantothenic acid, Dexpanthenol, Pantethine) · B6 ( Pyridoxine#, Pyridoxal phosphate, Pyridoxamine) · B7 ( Biotin) · B9 ( Folic acid, Dihydrofolic acid, Folinic acid) · B12 ( Cyanocobalamin, Hydroxocobalamin, Methylcobalamin, Cobamamide) · Choline
|
|
|
|
|
|
|
| Combinations |
|
|
|
|
|
|
|
|
