B vitamins

# Overview
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 B vitamins 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 B5 (pantothenic acid)
- Vitamin B6 (pyridoxine)
- Vitamin B7, also called vitamin H (biotin)
- Vitamin B9, also vitamin M and vitamin B-c (folic acid)
- Vitamin B12 (cyanocobalamin)
- Vitamin B8 (myo-inositol) is no longer classified as a vitamin because it is synthesized by the human body

# 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.

# 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. While they are non-"essential" in that they may be synthesized by the body from other starting materials, they have dietary significance. 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; (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-.
- Vitamin Bh  another name for Biotin
- Vitamin Bm ("mouse factor")  also used to designate Inositol
- Vitamin Bp (Choline) 
- Vitamin Bt (L-carnitine) 
- Vitamin Bv  a type of B6 but not Pyridoxine
- Vitamin Bw  a type of Biotin but not d-Biotin
- Vitamin Bx  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 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.
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
Vitamin B comes from a number of natural sources, including potatoes, bananas, lentils, chilli peppers, tempeh, liver oil, liver, turkey, and tuna. Nutritional yeast (or brewer's yeast) and molasses are especially good sources of Vitamin B. Marmite and the iconic Australian spread Vegemite bills itself 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 good source of B vitamins--in fact, beer is sometimes referred to as "liquid bread"--although this may be less true for filtered beersand the alcohol in beer impairs the body's ability to activate vitamins.
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.

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