B Vitamins

Thiamine or thiamin,Thiamine is pronounced "Thigh-a-min". sometimes called aneurin, is a water-soluble vitamin of the B complex (vitamin B1), whose phosphate derivatives are involved in many cellular processes. The best characterized form is thiamine diphosphate (ThDP), a coenzyme in the catabolism of sugars and amino acids. In yeast, ThDP is also required in the first step of alcoholic fermentation.

Thiamine is synthesized in bacteria, fungi and plants. Animals must cover all their needs from their food and insufficient intake results in a disease called beriberi affecting the peripheral nervous system (polyneuritis) and/or the cardiovascular system, with fatal outcome if not cured by thiamine administration.Mahan LK, Escott-Stump S, editors. Krause's food, nutrition, & diet therapy. 10th ed. Philadelphia: W.B. Saunders Company; 2000 In less severe deficiency, nonspecific signs include malaise, weight loss, irritability and confusion.Combs, G. F. Jr. The vitamins: Fundamental Aspects in Nutrition and Health''. 3rd Edition. Ithaca, NY: Elsevier Academic Press; 2008 Today, there is still a lot of work devoted to elucidating the exact mechanisms by which thiamine deficiency leads to the specific symptoms observed (see below). Finally, new thiamine phosphate derivatives have recently been discovered, emphasizing the complexity of thiamine metabolism and the need for more research in the field.

Riboflavin (E101), also known as vitamin B2, is an easily absorbed micronutrient with a key role in maintaining health in humans and animals. It is the central component of the cofactors FAD and FMN, and is therefore required by all flavoproteins. As such, vitamin B2 is required for a wide variety of cellular processes. Like the other B vitamins, it plays a key role in energy metabolism, and is required for the metabolism of fats, ketone bodies, carbohydrates, and proteins.

Milk, cheese, leafy green vegetables, liver, kidneys, legumes such as mature soybeans, yeast, mushrooms and almonds are good sources of vitamin B2, but exposure to light destroys riboflavin.

The name "riboflavin" comes from "ribose" and "flavin".

Niacin, also known as vitamin B3 or nicotinic acid, is an organic compound with the formula C5H4NCO2H. This colourless, water-soluble solid is a derivative of pyridine, with a carboxyl group (COOH) at the 3-position. Other forms of vitamin B3 include the corresponding amide, nicotinamide ("niacinamide"), where the carboxyl group has been replaced by a carboxamide group (CONH2), as well as more complex amides and a variety of esters. The terms niacin, nicotinamide, and vitamin B3 are often used interchangeably to refer to any member of this family of compounds, since they have the same biochemical activity.

Niacin is converted to nicotinamide and then to NAD and NADP in vivo. Although the two are identical in their vitamin activity, nicotinamide does not have the same pharmacological effects as niacin, which occur as side-effects of niacin's conversion. Nicotinamide does not reduce cholesterol or cause flushing. Nicotinamide may be toxic to the liver at doses exceeding 3 g/day for adults. Niacin is a precursor to NADH, NAD+, NADP+ and NADPH, which play essential metabolic roles in living cells. Niacin is involved in both DNA repair, and the production of steroid hormones in the adrenal gland.

Niacin is one of five vitamins associated with a pandemic deficiency disease: these are niacin (pellagra), vitamin C (scurvy), thiamin (beriberi), vitamin D (rickets), and vitamin A deficiency, a syndrome which has no common name but is one of the most common symptomatic deficiencies worldwide. In larger doses, niacin can reverse atherosclerosis by lowering low density lipoprotein (LDL) and favorably affecting other compounds.

Pantothenic acid, also called vitamin B5 (a B vitamin), is a water-soluble vitamin required to sustain life (essential nutrient). Pantothenic acid is needed to form coenzyme-A (CoA), and is critical in the metabolism and synthesis of carbohydrates, proteins, and fats. In chemical structure, it is the amide between D-pantoate and beta-alanine. Its name is derived from the Greek pantothen () meaning "from everywhere" and small quantities of pantothenic acid are found in nearly every food, with high amounts in whole-grain cereals, legumes, eggs, meat, and royal jelly. It is commonly found as its alcohol analog, the provitamin panthenol, and as calcium pantothenate. Pantothenic acid is an ingredient in some hair and skin care products.

Vitamin B6 is a water-soluble vitamin and is part of the vitamin B complex group. Pyridoxal phosphate (PLP) is the active form and is a cofactor in many reactions of amino acid metabolism, including transamination, deamination, and decarboxylation. PLP also is necessary for the enzymatic reaction governing the release of glucose from glycogen.

Biotin is a water-soluble B-complex vitamin which is composed of an ureido (tetrahydroimidizalone) ring fused with a tetrahydrothiophene ring. A valeric acid substituent is attached to one of the carbon atoms of the tetrahydrothiophene ring. Biotin is a coenzyme in the metabolism of fatty acids and leucine, and it plays a role in gluconeogenesis.

Vitamin B12, also called cobalamin, is a water soluble vitamin with a key role in the normal functioning of the brain and nervous system, and for the formation of blood. It is one of the eight B vitamins. It is normally involved in the metabolism of every cell of the body, especially affecting DNA synthesis and regulation, but also fatty acid synthesis and energy production.

Vitamin B12 is a class of chemically-related compounds, all of which have vitamin activity. It is structurally the most complicated vitamin and it contains the biochemically rare element cobalt. Biosynthesis of the basic structure of the vitamin can only be accomplished by bacteria, but conversion between different forms of the vitamin can be accomplished in the human body. A common synthetic form of the vitamin, cyanocobalamin, does not occur in nature, but is used in many pharmaceuticals and supplements, and as a food additive, due to its stability and lower cost. In the body it is converted to the physiological forms, methylcobalamin and adenosylcobalamin, leaving behind the cyanide, albeit in minimal concentration. More recently, hydroxocobalamin, methylcobalamin, and adenosylcobalamin can also be found in more expensive pharmacological products and food supplements. The utility of these is presently debated.

Historically, vitamin B12 was discovered from its relationship to the disease pernicious anemia, which is an autoimmune disease that destroys parietal cells in the stomach that secrete intrinsic factor. Intrinsic factor is crucial for the normal absorption of B12, so a lack of intrinsic factor, as seen in pernicious anemia, causes a vitamin B12 deficiency. Many other subtler kinds of vitamin B12 deficiency, and their biochemical effects, have since been elucidated.

Adenine is a nucleobase (a purine derivative) with a variety of roles in biochemistry including cellular respiration, in the form of both the energy-rich adenosine triphosphate (ATP) and the cofactors nicotinamide adenine dinucleotide (NAD) and flavin adenine dinucleotide (FAD), and protein synthesis, as a chemical component of DNA and RNA.Definition of Adenine from the Genetics Home Reference - National Institutes of Health The shape of adenine is complementary to either thymine in DNA or uracil in RNA.

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 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. 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 etc.).

4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA) is an organic compound with the formula H2NC6H4CO2H. PABA is a white crystalline substance that is only slightly soluble in water. It consists of a benzene ring substituted with an amino group and a carboxyl group.

Orotic acid is a heterocyclic compound and an acid; it is also known as pyrimidinecarboxylic acid. It was once believed to be part of the vitamin B complex and was called vitamin B13, but it is now known that it is not a vitamin but is instead manufactured in the body by intestinal flora.

Its salts, known as orotates, are sometimes used as mineral carriers in some dietary supplements, to increase their bioavailability. Lithium orotate is the most frequently used in this manner.

Pangamic acid is an ester derived from gluconic acid and dimethylglycine.Recent data on the structure of pangamic acid (vitamin B15). Telegdy Kovats, Laszlo; Berndorfer-Kraszner, Eva; Juhasz, Agnes; Gabor, Tamas. Acta Alimentaria Academiae Scientiarum Hungaricae (1976), 5(3), 281-8. It was first isolated by Ernst T. Krebs from apricot kernels,KREBS E T Sr; KREBS E T Jr; BEARD H H; MALIN R; HARRIS A T; BARTLETT C L Pangamic acid sodium: a newly isolated crystalline water-soluble factor; a preliminary report. International record of medicine and general practice clinics (1951), 164(1), 18-23. and has since been identified in some foods such as pulsesSingh, Jagdev; Handa, Mrs. Geeta; Nandi, L. N.; Manavalan, R.; Atal, C. K. D-Gluconodimethylaminoacetic acid from natural sources. Indian Drugs (1983), 20(5), 185-9. and rice bran.

Pangamic acid was also promoted by Krebs as vitamin B15, but it is not accepted as a vitamin because it has not been shown to be essential in the human diet, and a deficiency in consumption of pangamic acid is not known to be associated with any disease."Vitamin B15 - Pangamic Acid", Elson M. Haas M.D.

The calcium salt of pangamic acid, calcium pangamate, is used as a mineral supplement. Like thiamine, pangamic acid causes a temporary drop in blood pressure lasting for about 20 minutes.

Dimethylglycine (DMG) is a derivative of the amino acid glycine found in beans and liver. It can be formed from trimethylglycine upon the loss of one of its methyl groups. It is also a byproduct of the metabolism of choline.

When DMG was first discovered, it was referred to as vitamin B16, but unlike true B vitamins, deficiency of DMG in the diet does not lead to any ill effects. In legal terms, it has been deemed not to be a vitamin but a food product and, as such, is available without a practitioner or prescription.

Amygdalin (from Greek: '' ?almond?), C20H27NO11, is a glycoside initially isolated from the seeds of the tree Prunus dulcis, also known as bitter almonds, by Pierre-Jean Robiquet

and A. F. Boutron-Charlard in 1803, and subsequently investigated by Liebig and Wöhler in 1830, and others. Several other related species in the genus of Prunus, including apricot (Prunus armeniaca) and black cherry (Prunus serotina''), also contain amygdalin. It was promoted as a cancer cure by Ernst T. Krebs under the name "Vitamin B17", but studies have found it to be ineffective.

Carnitine is a quaternary ammonium compound biosynthesized from the amino acids lysine and methionine. In living cells, it is required for the transport of fatty acids from the cytosol into the mitochondria during the breakdown of lipids (or fats) for the generation of metabolic energy. It is often sold as a nutritional supplement. Carnitine was originally found as a growth factor for mealworms and labeled vitamin Bt. Carnitine exists in two stereoisomers: its biologically active form is L-carnitine, while its enantiomer, D-carnitine, is biologically inactive.

Inositol or cyclohexane-1,2,3,4,5,6-hexol is a chemical compound with formula 6126 or (-CHOH-)6, a sixfold alcohol (polyol) of cyclohexane. It exists in nine possible stereoisomers, of which the most prominent form, widely occurring in nature, is '''cis-1,2,3,5-trans-4,6-cyclohexanehexol, or myo-inositol'.

Myo-inositol plays an important role as the structural basis for a number of secondary messengers in eukaryotic cells, including inositol phosphates, phosphatidylinositol (PI) and phosphatidylinositol phosphate (PIP) lipids. It is found in many foods, in particular, in cereals with high bran content, nuts, beans, and fruit, especially cantaloupe melons and oranges. Inositol is not considered a vitamin itself because it can be synthesised by the body.

Myo''-Inositol was classified as a member of the vitamin B complex (often referred to as vitamin B8)]}). However, because it is produced by the human body it is not an essential nutrient. It should be noted, however, that substances such as niacin and choline can also be synthesized in the body, but are not made in amounts considered adequate for good health, and are classified as essential nutrients.

Category: File - :Choline-skeletal.png|thumb|right|The N,N,N-trimethylethanolammonium cation, with an undefined counteranion, X−

Choline is a water-soluble essential nutrient.

"Choline, PDRHealth"Choline" (An interview with Steven Zeisel, Editor-in-Chief of the Journal of Nutritional Biochemistry), Radio National Health Report with Norman Swan, Monday 17 April 2000"[http://www.nap.edu/openbook.php?record_id=6015&page=390]" Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline (1998), Institute of Medicine. It is usually grouped within the Vitamin B complex. Choline generally refers to the various quaternary ammonium salts containing the N,N,N-trimethylethanolammonium cation.

These naturally-occuring ammonium salts are found in the lipids that make up cell membranes and in the neurotransmitter acetylcholine. Adequate intakes (AI) for this micronutrient of between 425 to 550 milligrams daily, for adults, have been established by the Food and Nutrition Board of the Institute of Medicine of the National Academy of Sciences.

4-Aminobenzoic acid (also known as para-aminobenzoic acid or PABA) is an organic compound with the formula H2NC6H4CO2H. PABA is a white crystalline substance that is only slightly soluble in water. It consists of a benzene ring substituted with an amino group and a carboxyl group.