B vitamins

B vitamin supplement tablets

The B vitamins are eight water-soluble vitamins that play important roles in cell metabolism. Historically, the B vitamins were once thought to be a single vitamin, referred to as vitamin B (much like how people refer to vitamin C or vitamin D). Later research showed that they are chemically distinct vitamins that often coexist in the same foods. Supplements containing all eight are generally 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).

List of B vitamins

• Vitamin B₁ (thiamine)
• Vitamin B₂ (riboflavin)
• Vitamin B₃ (niacin, includes nicotinic acid and nicotinamide), vitamin PP
• Vitamin B₅ (pantothenic acid)
• Vitamin B₆ (pyridoxine)
• Vitamin B₇ (biotin), vitamin H
• Vitamin B₉ (folic acid), vitamin M, vitamin B-c
• Vitamin B₁₂ (various cobalamins; commonly cyanocobalamin in vitamin supplements)

note:

• Vitamin B₄ (adenine, DNA metabolite) is no longer classified as a vitamin because it is synthesized by the human body
• Vitamin B₈ (myo-inositol, adenylic acid, DNA metabolite) is no longer classified as a vitamin because it is synthesized by the human body
• Vitamin B₁₅ (pangamic acid) is not widely accepted as a vitamin because it has not been shown to be essential in the human diet
• Vitamin B₁₇ (amygdalin, laetrille) is not yet classified

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, 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.
Vitamin B5	pantothenic acid	Deficiency can result in acne and paresthesia, although it is uncommon.
Vitamin B6	pyridoxine	Deficiency may lead to anemia, 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.
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 causes 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. In rare extreme cases, paralysis can result.

Related nutrients

Many of the following substances have been referred to as vitamins because they were believed to be vitamins at one time, and they are relevant to vitamin nomenclature in that the numbers that were assigned to them form "gaps" in the series of B-vitamin names. Some of them, though not essential to humans, are essential in the diets of other organisms; others have no known nutritional value. See also Orthomolecular medicine.

• Vitamin B₄: Adenine, a nucleobase.
• Vitamin B₇: "Vitamin I" of Centanni E. (1935) — also called 'Enteral factor' — is a water and alcohol soluble rice-bran factor which 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.
• Vitamin B₈: adenosine monophosphate, or alternately inositol has also been called vitamin B₈
• Vitamin B₁₀: para-aminobenzoic acid, or 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. (L-carnitine) is called Vitamin B₁₁ in France.
• Vitamin B₁₃: Orotic acid.
• Vitamin B₁₄: cell proliferant, anti-anemia, rat growth, and antitumor pterin phosphate named by Earl R. Norris (biochemist of folic acid fame). 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 6-O-(dimethylaminoacetyl)-D-gluconic acid (Pangamic acid)
• Vitamin B₁₆ (dimethylglycine) – also known as DMG. (However Lipoic acid was discovered and named a B-Vitamin after B15 and before B17)
• Vitamin B₁₇ (Amygdalin, Nitrilosides, or laetrile) – A substance 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.
• 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 – another name for Biotin
• Vitamin B_m ("mouse factor") – also used to designate Inositol
• Vitamin B_p (Choline) –
• 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 – another name for PABA (para-Aminobenzoic acid)
• Lipoic acid –

Note: B₁₆, B₁₇, B₁₈, B₁₉, B₂₀, B₂₁ & B₂₂ do not appear to be animal factors but are claimed by some naturopaths as human therapedic factors.

Health benefits

The B vitamins often work together to deliver a number of health benefits to the body. B vitamins have been shown to:

• Support and increase the rate of metabolism
• Maintain healthy skin 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.

Together, they also help combat the symptoms and causes of stress, depression, and cardiovascular disease.

All B vitamins are water soluble, and are dispersed throughout the body. Most of the B vitamins must be replenished daily, since any excess is excreted in the urine. A six year cobalamin store can be found in the liver, despite its water soluble nature.

Vitamin B sources

Different B vitamins come from different natural sources, such as potatoes, bananas, lentils, chilli peppers, tempeh, liver oil, liver, turkey, tuna, Nutritional yeast (or brewer's yeast) and molasses. Marmite and Vegemite bill themselves as "one of the world's richest known sources of vitamin B". As might be expected, due to its high content of brewer's yeast, beer is a source of B vitamins, although this may be less true for filtered beersand the alcohol in beer impairs the body's ability to activate vitamins.

The B-12 vitamin is of note because it is not available from plant products, making B-12 deficiency a concern for vegans. Manufacturers of plant-based foods will sometimes report B-12 content, leading to confusion about what sources yield B-12. The confusion arises because the standard US Pharmacopeia (USP) method for measuring the B-12 content does not measure the B-12 directly. Instead, it measures a bacterial response to the food. Chemical variants of the B-12 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 B-12 content in other types of foods as well.

Another popular means of increasing one's vitamin B intake is through the use of dietary supplements purchased at supermarkets, health centers, or natural food stores. B vitamins are also commonly added to energy drinks.

There are also vitamin B injections that can be taken to reverse deficiencies (Can someone else expand on this, have they been shown to be good or bad?)

Mnemonic

One mnemonic to remember the most commonly referenced B vitamins is "The (B1, Thiamine) Rhythm (B2, Riboflavin) Nearly (B3, Niacin) Proved (B6, Pyridoxine) Contagious (B12, Cobalamin)".

External links

• How B Vitamins Work at HowStuffWorks