A water-soluble vitamin (B1) which acts as an enzyme co-factor in the oxidation of glucose. A deficiency leads to beri-beri, a disease once common, especially in SE Asia, where polished rice, low in vitamin B1, was the staple food. Thiamine is more rapidly degraded in the cooking process when the medium is alkaline; thus, the use of soda in the boiling of vegetables reduces thiamine concentrations.
Thiamine was first discovered in 1910 by Umetaro Suzuki in Japan when researching how rice bran cured patients of Beriberi. There are three known thiamine phosphate derivatives: thiamine monophosphate (ThMP), thiamine diphosphate (ThDP) and thiamine triphosphate (ThTP).
Thiamine diphosphate (ThDP) or thiamine pyrophosphate (TPP) is a coenzyme for pyruvate dehydrogenase, α-ketoglutarate dehydrogenase, branched-chain alpha-keto acid dehydrogenase, and transketolase. TPP is synthesized by the enzyme thiamine pyrophosphokinase, which requires free thiamine, magnesium, and adenosine triphosphate.
Thiamine triphosphate (ThTP) was long considered a specific neuroactive form of thiamine.
Nutrition
Also known as vitamin B1, thiamine plays an important role in helping the body convert carbohydrates and fat into energy.
Good sources
Thiamine is found naturally in the following foods, each of which contains at least 0.1mg of the vitamin per 28-100g (1-3.5oz): - Green peas - Spinach - Liver - Beef - Navy beans - Nuts - Pinto beans - Soybeans
Deficiency
Systemic thiamine deficiency can lead to myriad problems including neurodegeneration, wasting, and death. A lack of thiamine can be caused by malnutrition, 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 assertained by measuring erythrocyte levels of transketolase.
Overdose
The only known cases of thiamine overdose occurred with thiamine injections. (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
Research
High doses
The RDA in most countries is set at about 1.4 mg.
Benefits for autism
Derrick Lonsdale lead a successful study on the treatment of autism spectrum children with thiamine.
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