B vitamins

B vitamin supplement tablets

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.).

List of B vitamins

• Vitamin B₁ (thiamine)
• Vitamin B₂ (riboflavin)
• Vitamin B₃ (niacin or niacinamide)
• Vitamin B₅ RYZE (pantothenic acid)
• Vitamin B₆ (pyridoxine, pyridoxal, or pyridoxamine, or pyridoxine hydrochloride)
• Vitamin B₇ (biotin)
• Vitamin B₉GAREN RUNS OUT OF THE BUSH AND KILL YOU (folic acid)
• Vitamin B₁₂ (various cobalamins; commonly cyanocobalamin in vitamin supplements)

Health benefits

The B vitamins may be 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 - when consumed in food, but not when ingested in vitamin tablet form.

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.

B vitamins have also been hypothesized to improve 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.

B vitamin toxicity

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	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	riboflavin	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	niacin	35 mg/day from supplements, drugs or fortified food	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. 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.
Vitamin B5	pantothenic acid	None	No known toxicity
Vitamin B6	pyridoxine	100 mg/day from supplements, drugs or fortified food	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].
Vitamin B7	biotin	None	No known toxicity
Vitamin B9	folic acid	1 mg/day	Masks B12 deficiency, which can lead to permanent neurological damage
Vitamin B12	cobalamin	None established.	Acne-like rash [causality is not conclusively established].

B vitamin sources

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. 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, their bioavailability ranges from poor to negative as drinking ethanol inhibits absorption of thiamine (B₁), riboflavin (B₂), niacin (B₃), biotin (B₇), and folic acid (B₉). 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.

Vitamin B may also be delivered by injection to reverse deficiencies.

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 with claims that this will cause the consumer to "sail through your day without feeling jittery or tense." 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]."

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. 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…" 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. 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. However, for "most typical consumers of energy supplements or drinks, B vitamins are nothing more than a 'gimmick'."

Related nutrients

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 B₄: adenine, a nucleobase, is synthesized by the human body.

• 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.
• 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 accepted scientific evidence.
• 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.
• Vitamin B_h: biotin
• Vitamin B_m: "mouse factor": also used to designate inositol
• Vitamin B_p: choline Choline is only required for survival of some mutants. Most commonly it is synthesized in vivo de novo. May be added as supplement especially when methionine supply is limited

• Vitamin B_t: L-carnitine
• Vitamin B_v: a type of B₆ but not pyridoxine
• Vitamin B_w: a type of biotin but not d-biotin
• Vitamin B_x: para-aminobenzoic acid

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.