Thiamine or thiamin, also known as vitamin B1, is one of the B vitamins. It is a colorless compound with chemical formula C12H17N4OS. It is soluble in water and insoluble in alcohol. Thiamine decomposes if heated. Its chemical structure contains a pyrimidine ring and a thiazole ring.

Thiamin, also called vitamin B1, is used in many different body functions and deficiencies may have far reaching effects on the body, yet very little of this vitamin is stored in the body, and depletion of this vitamin can happen within 14 days.

History

Before the 20th century, no one had heard of vitamins. It was Christiaan Eijkman who first pointed out a substance in rice skin, which was later to be known as vitamin B1. For this, and for his new ways of investigating, as well as for the methods he used to control diseases caused by vitamin deficiency, Eijkman was awarded the 1929 Nobel Prize in Physiology or Medicine.

Thiamine was first discovered in 1910 by Umetaro Suzuki in Japan when researching how rice bran cured patients of beriberi. He named it aberic acid. He did not determine its chemical composition, nor that it was an amine.

It was first crystallized by Jansen and Donath in 1926 (they named it aneurin, for antineuritic vitamin).

Its chemical composition and synthesis was finally reported by Robert R. Williams in 1935. He also coined the name for it, thiamine.

Thiamine phosphate derivatives

There are four known natural thiamine phosphate derivatives: thiamine monophosphate (ThMP), thiamine diphosphate (ThDP), thiamine triphosphate (ThTP) and the recently discovered adenosine thiamine triphosphate (AThTP).

Thiamine pyrophosphate

Thiamine pyrophosphate (TPP), also known as thiamine diphosphate (ThDP), is a coenzyme for several enzymes that catalyze the dehydrogenation (decarboxylation and subsequent conjugation to Coenzyme A) of alpha-keto acids. Examples include:

• In mammals:
  • pyruvate dehydrogenase and α-ketoglutarate dehydrogenase (metabolism of carbohydrates)
  • branched-chain alpha-keto acid dehydrogenase
  • 2-hydroxyphytanoyl-CoA lyase
  • transketolase (functions in the pentose phosphate pathway to synthesize NADPH and the pentose sugars deoxyribose and ribose )

• In other species:
  • pyruvate decarboxylase (in yeast)
  • several additional bacterial enzymes

TPP is synthesized by the enzyme thiamine pyrophosphokinase, which requires free thiamine, magnesium, and adenosine triphosphate.

Thiamine triphosphate

Thiamine triphosphate (ThTP) was long considered a specific neuroactive form of thiamine.

However, recently it was shown that ThTP exists in bacteria, fungi, plants and animals suggesting a much more general cellular role. In particular in E. coli it seems to play a role in response to amino acid starvation.

Adenosine thiamine triphosphate

Adenosine thiamine triphosphate (AThTP) or thiaminylated adenosine triphosphate has recently been discovered in Escherichia coli where it accumulates as a result of carbon starvation. In E. coli, AThTP may account for up to 20 % of total thiamine.

It also exists in lesser amounts in yeast, roots of higher plants and animal tissues.

Nutrition

Also known as vitamin B1, thiamine plays an important role in helping the body metabolize carbohydrates and fat to produce energy. It is essential for normal growth and development and helps to maintain proper functioning of the heart and the nervous and digestive systems. Thiamine is water-soluble and cannot be stored in the body; however, once absorbed, the vitamin is concentrated in muscle tissue.

Vitamin B1 - thiamine - is required for

Thiamin may enhance circulation, helps with blood formation and the metabolism of carbohydrates. It is also required for the health of the nervous system and is used in the biosynthesis of a number of cell constituents, including the neurotransmitter acetylcholine and gamma-aminobutyric acid (GABA). It is used in the manufacture of hydrochloric acid, and therefore plays a part in digestion.

Deficiency of vitamin B1

A deficiency will result in beriberi, and minor deficiencies may be indicated with extreme fatigue, irritability, constipation, edema and an enlarged liver. Forgetfulness, gastrointestinal disturbances, heart changes, irritability, labored breathing and loss of appetite may also be experienced.

Thiamin is also a miraculous nutrient, somebody suffering from beriberi, scarcely able to lift their head from their pillow, will respond quickly from injected thiamin, and will be on their feet within a matter of hours.

With too little thiamin around a person may also experience nervousness, numbness of the hands and feet, pain and sensitivity, poor coordination, tingling sensations, weak and sore muscles, general weakness and severe weight loss.

It is also great for the brain and may help with depression and assist with memory and learning. In children it is required for growth and has shown some indication to assist in arthritis, cataracts as well as infertility.

Deficiency

Systemic thiamine deficiency can lead to myriad problems including neurodegeneration, wasting, and death. A lack of thiamine can be caused by malnutrition, alcoholism, a diet high in thiaminase-rich foods (raw freshwater fish, raw shellfish, ferns) and/or foods high in anti-thiamine factors (tea, coffee, betel nuts).

Well-known syndromes caused by thiamine deficiency include Wernicke-Korsakoff syndrome and beriberi, diseases also common with chronic alcoholism.

Diagnostic testing for B1 deficiency

A positive diagnosis test for Thiamine deficiency can be ascertained by measuring the activity of transketolase in erythrocyte . Thiamine can also be skeeted directly in whole blood following the conversion of thiamine to a fluorescent thiochrome derivative.

Genetic diseases

It has been suggested that this section be split into a new article entitled Thiamine-responsive megaloblastic anemia with diabetes mellitus and sensorineural deafness. (Discuss)

Genetic diseases of thiamine transport are rare but serious. Thiamine Responsive Megaloblastic Anemia with diabetes mellitus and sensorineural deafness (TRMA) is an autosomal recessive disorder caused by mutations in the gene SLC19A2,[ a high affinity thiamine transporter. TRMA patients do not show signs of systemic thiamine deficiency, suggesting redundancy in the thiamine transport system. This has led to the discovery of a second high affinity thiamine transporter, SLC19A3.

Mendelian Inheritance in Man (OMIM) 249270

Dosage

The dosage underneath is the Recommended Dietary Allowance (RDA), but be aware that this dosage is the minimum that you require per day, to ward off serious deficiency of this particular nutrient. In the therapeutic use of this nutrient, the dosage is usually increased considerably, but the toxicity level must be kept in mind.

Male 1.4 mg per day and female 1.0 mg per day, although 50 mg is usually used in supplementation.

High doses

The RDA in most countries is set at about 1.4 mg. However, tests on volunteers at daily doses of about 50 mg have shown an increase in mental acuity.

Toxicity and symptoms of high intake

Thiamin toxicity is uncommon; as excesses are readily excreted, although long-term supplementation of amounts larger than 3 gram have been known to cause toxicity.

Best used with

Thiamin should be taken with the B group vitamins and manganese.

When more may be required

When taking alcohol, antacids and birth control pills or if you have hormone replacement therapy, you need to look at your thiamin intake. People suffering from depression or anxiety and those passing large volumes of urine, or suffering from an infection may all require more thiamin.

Enemy of vitamin B1

Thiamin is destroyed in cooking, and intake may be low if the diet is high in refined foods. Do not add soda if you are boiling green vegetables since soda is alkaline and will destroy thiamin.

Other interesting points

It is thought that thiamin can be useful for motion sickness in air and sea travel, and that this vitamin also repels insects when excreted through the skin.

Thiamine as an insect repellent

Some studies suggest that taking thiamine (vitamin B1) 25 mg to 50 mg three times per day is effective in reducing mosquito bites. A large intake of Thiamine produces a skin odor that is not detectable by humans, but is disagreeable to female mosquitoes. Thiamine takes more than 2 weeks before the odor fully saturates the skin. With the advances in topical preparations there is an increasing number of Thiamine based repellent products. Whilst there is considerable anecdotal evidence of Thiamine products being effective in the field (Australia, US and Canada), there has yet to be any clinical trials run to demonstrate the efficacy of these products.

Benefits for autism

Derrick Lonsdale lead a successful study on the treatment of autism spectrum children with thiamine. This work is controversial linking diet with autism.

Food sources of vitamin B1

Sunflower seeds, peanuts, wheat bran, beef liver, pork, seafood, egg-yolk, beans all contain good amounts of thiamin.

Thiamine is found naturally in the following foods, each of which contains at least 0.1 mg of the vitamin per 28-100 g (1-3.5 oz): Green peas, Spinach, Liver Beef, Pork, Navy beans, Nuts, Pinto beans, Bananas, Soybeans, Whole-grain and Enriched Cereals, Breads, Yeast,the aleurone layer of unpolished rice, and Legumes.

Sources: Zest of Life, Nobleprize.org and Wikipedia, the free encyclopedia