Pantothenic acid

Overview
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. Chemically 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.

Biological role
Only the dextrorotatory (D) isomer of pantothenic acid possesses biologic activity. The levorotatory (L) form may antagonize the effects of the dextrorotatory isomer.

Pantothenic acid is used in the synthesis of coenzyme A (abbreviated as CoA). Coenzyme A may act as an acyl group carrier to form acetyl-CoA and other related compounds; this is a way to transport carbon atoms within the cell. The transfer of carbon atoms by coenzyme A is important in cellular respiration, as well as the biosynthesis of many important compounds such as fatty acids, cholesterol, and acetylcholine.

Since pantothenic acid participates in a wide array of key biological roles, it is considered essential to all forms of life. As such, deficiencies in pantothenic acid may have numerous wide-ranging effects, as discussed below

Daily requirement
Pantothenate in the form of pantethine is considered to be the more active form of the vitamin in the body, but is unstable at high temperatures or when stored for long periods, so calcium pantothenate is the more usual form of vitamin B5 when it is sold as a dietary supplement. 10 mg of calcium pantothenate is equivalent to 9.2 mg of pantothenic acid.
 * United Kingdom RDA: 6 mg/day

Deficiency
Pantothenic acid deficiency is exceptionally rare and has not been thoroughly studied. In the few cases where deficiency has been seen (victims of starvation and limited volunteer trials), nearly all symptoms can be reversed with the return of pantothenic acid.

Symptoms of deficiency are similar to other vitamin B deficiencies. Most are minor, including fatigue, allergies, nausea, and abdominal pain. In a few rare circumstances more serious (but reversible) conditions have been seen, such as adrenal insufficiency and hepatic encephalopathy.

Notably, painful burning sensations of the feet were reported in tests conducted on volunteers. Deficiency of pantothenic acid may explain similar sensations reported in malnourished prisoners of war.

Disputed uses
Given pantothenic acid's prevalence among living things and the limited body of studies in deficiency, many "alternative" uses of pantothenic acid have been devised.

Hair care
Mouse models identified skin irritation and loss of hair color as possible results of severe pantothenic acid deficiency. As a result, the cosmetic industry began adding pantothenic acid to various cosmetic products, including shampoo. These products, however, showed no benefits in human trials. Despite this, many cosmetic products still advertise pantothenic acid additives.

Acne
Following from discoveries in mouse trials, in the late 1990s a small study was published promoting the use of pantothenic acid to treat acne vulgaris.

According to a study published in 1995 by Dr. Lit-Hung Leung, high doses of Vitamin B5 resolved acne and decreased pore size. Dr. Leung also proposes a mechanism, stating that CoA regulates both hormones and fatty-acids, and without sufficient quantities of pantothenic acid, CoA will preferentially produce androgens. This causes fatty acids to build up and be excreted through sebaceous glands, causing acne. Leung's study gave 45 Asian males and 55 Asian females varying doses of 10-20g of pantothenic acid (100,000%-200,000% of the US Daily Value), 80% orally and 20% through topical cream. Leung noted improvement of acne within one week to one month of the start of the treatment.

Critics are quick to point out the flaws in Dr. Leung's study, however. Dr. Leung's study was not a double-blind placebo controlled trial. To date, the only study looking at the effect of Vitamin B5 on acne is Dr. Leung's, and few if any dermatologists prescribe high-dose pantothenic acid. Furthermore, there is no evidence documenting acetyl-CoA regulation of androgens instead of fatty acids in times of stress or limited availability, since fatty acids are also necessary for life.

Diabetic Peripheral polyneuropathy
28 out of 33 patients (84,8%) previously treated with alpha-lipoic acid for peripheral polyneuropathy reported further improvement after combination with pantothenic acid. The theoretical basis for this is that both substances intervene at different sites in pyruvate metabolism and are thus more effective than one substance alone. Additional clinical findings indicated that diabetic neuropathy may occur in association with a latent prediabetic metabolic disturbance, and that the symptoms of neuropathy can be favourably influenced by the described combination therapy, even in poorly controlled diabetes.

Today, many companies offer Vitamin B5 supplements aimed at reducing acne. The recommended treatment course, however, can be perceived as difficult and expensive. Many sites suggest starting off the first three days with 5g and then moving up to 10g a day for three months. Since the largest pill available is 1g, this can result in as many as 10 pills a day or more if smaller pills are taken. The average cost for a bottle of 200 B5 500mg tablets is $10, so the cost can be steep. B5 sold as a powder that can be dissolved in water and drunk is generally a cheaper and for some people a more convenient alternative. Furthermore, after three months many users suggest decreasing to 3-5g a day, with some claiming 1 g/day is sufficient.

Synonyms

 * Pantothenate
 * Vitamin B5
 * Vilantae — a brand name for the supplement when used to treat acne.

Enzymes

 * Ketopantoate hydroxymethyltransferase