B vitamins/ja: Difference between revisions

! Vitamin !! Tolerable Upper Intake Level (UL) !! Harmful effects

  ! Vitamin B₁

| None || 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.

  ! Vitamin B₂  

| None || 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.

  !Vitamin B₃  

| US UL = 35 mg as a dietary supplement || 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 (physiology)|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. Medical practitioners prescribe recommended doses up to 2000 mg per day of niacin in either immediate-release or slow-release formats, to lower plasma triglycerides and low-density lipiprotein cholesterol.

  ! Vitamin B₅  

| None || No toxicity known.

  ! Vitamin B₆  

| US UL = 100 mg/day; EU UL = 25 mg/day || See [[Megavitamin-B6 syndrome|Megavitamin-B₆ syndrome]] for more information.

  ! Vitamin B₇  

| None || No toxicity known.

  ! Folate

| 1 mg/day || Masks B₁₂ deficiency, which can lead to permanent [[neurological]] damage.

  ! Vitamin B₁₂  

| None established || Skin and spinal lesions. Acne-like rash [causality is not conclusively established].

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==Discovery==

! Vitamin!! Name !! Discoverer!!Date!!Notes

! rowspan="2" |Vitamin&nbsp;B₁  

| rowspan="2" |[[Thiamine]] || [[Umetaro Suzuki]]||1910||Failed to gain publicity.

| [[Casimir Funk]] || 1912||

! Vitamin&nbsp;B₂

| [[Riboflavin]] || D.T Smith and E.G Hendrick

| 1926|| [[Max Tishler]] invented methods for [[chemical synthesis|synthesizing]] it.

! Vitamin&nbsp;B₃

| [[Niacin (substance)|Niacin]] || [[Conrad Elvehjem]]|| 1937||

! Vitamin&nbsp;B₅

| [[Pantothenic acid]] || [[Roger J. Williams]]||1933||

! Vitamin&nbsp;B₆  

| [[Pyridoxine]] etc. || [[Paul Gyorgy]]||1934||

! Vitamin&nbsp;B₇

| [[Biotin]] || colspan=3|Research by multiple independent groups in the early 1900s; credits for discovery include [[Margaret Averil Boas]] (1927), and [[Dean Burk]].

! Vitamin&nbsp;B₉  

| [[Folic acid]] || [[Lucy Wills]]||1933||

!Vitamin&nbsp;B₁₂

| [[Cobalamin]]s || colspan=3|[[Vitamin B12#History|Five people]] have been awarded [[Nobel Prize]]s for direct and indirect studies of vitamin B₁₂: [[George Whipple]], [[George Minot]] and [[William P. Murphy|William Murphy]] (1934), [[Alexander R. Todd]] (1957), and [[Dorothy Hodgkin]] (1964).

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==Related compounds==

Many of the following substances have been referred to as vitamins as they were once believed to be vitamins. They are no longer considered as such, and the numbers that were assigned to them now form the "gaps" in the true series of B-complex vitamins described above (for example, 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 B₄''': can refer to the distinct chemicals [[choline]], [[adenine]], or [[carnitine]].

** Choline is [[biosynthesis|synthesized]] by the human body, but not sufficiently to maintain good health, and is now considered an essential dietary nutrient.

** Adenine is a [[nucleobase]] synthesized by the human body.

** Carnitine is an essential dietary nutrient for certain worms, but not for humans.

* '''Vitamin B₈''': [[adenosine monophosphate]] (AMP), also known as adenylic acid. Vitamin B₈ may also refer to [[inositol]].

* '''Vitamin B₁₀''': [[4-Aminobenzoic acid|''para''-aminobenzoic acid]] (pABA or PABA), a chemical component of the folate molecule produced by plants and bacteria, and found in many foods. It is best known as a [[ultraviolet light|UV]]-blocking [[sunscreen]] applied to the skin, and is sometimes taken orally for certain medical conditions.

* '''Vitamin B₁₁''': pteroylheptaglutamic acid (PHGA; chick growth factor). Vitamin Bc-conjugate was also found to be identical to PHGA. Derivative of [[folate]] ("pteroylmonoglutamic acid" in this nomenclature).

* '''Vitamin B₁₃''': [[orotic acid]].

* '''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]], also known as pangamate. Promoted in various forms as a dietary supplement and drug; considered unsafe and subject to seizure by the US [[Food and Drug Administration]].

* '''Vitamin B₁₆''': [[dimethylglycine]] (DMG) is synthesized by the human body from choline.

* '''Vitamin B₁₇''': pseudoscientific name for the poisonous compound [[amygdalin]], also known as the equally pseudoscientific name "nitrilosides" despite the fact that it is a single compound. Amygdalin can be found in various plants, but is most commonly extracted from apricot pits and other similar fruit kernels. Amygdalin is hydrolyzed by various intestinal enzymes to form, among other things, hydrogen cyanide, which is toxic to human beings when exposed to a high enough dosage. Some proponents claim that amygdalin is effective in cancer treatment and prevention, despite its toxicity and a lack of scientific evidence.

* '''Vitamin B₂₀''': <small>L</small>-carnitine.

* '''Vitamin B_f''': carnitine.

* '''Vitamin B_m''': [[inositol|''myo''-inositol]], also called "mouse antialopaecia factor".

* '''Vitamin B_p''': "antiperosis factor", which prevents [[perosis]], a leg disorder, in [[chicken|chicks]]; can be replaced by choline and manganese salts.

* '''Vitamin B_T''': carnitine.

* '''Vitamin B_v''': a type of B₆ other than pyridoxine.

* '''Vitamin B_W''': a type of biotin other than d-biotin.

* '''Vitamin B_x''': an alternative name for both pABA (see vitamin B₁₀) and [[pantothenic acid]].

{{Vitamins}}

{{Nutritional pathology}}