Thiamine or vitamin B1

Thiamine or thiamin or vitamin B1 named as the “thio-vitamine”(sulfur-containing vitamin”) is a water-soluble vitamin of the B complex. The best-characterized form is thiamine pyrophosphate (TPP), a coenzyme in the catabolism of sugars and amino acids.

There are some Function of thiamin

·  Thiamine is mainly the transport form of the vitamin, while the active forms are phosphorylated thiamine

      derivatives.

·         Thiamine monophosphate

There is no known physiological role of ThMP

·      Thiamine diphosphate

·         ThDP is a coenzyme for several enzymes that catalyze the transfer of two carbon units and in the 

       particular the dehydrogenation of 2-oxoacid.

·         Thiamine triphosphate was long consider a specific neuroactive form of thiamine.

·         Adenosine thiamine triphosphate, it  accumulates  as a result of carbon starvation.

·         Adenosine thiamine diphosphate exsists in small amounts in vertebrate liver, but its role remains unknown.

Source of Thiamine

Complex thiamine biosynthetic pathways occur in bacteria, some protozoan, plants and fungi.

The thiazole and pyrimidine moieties are synthesized separately and then assembled to form ThMP by thiamine phosphate synthase.The biosynthetic pathways are regulated by riboswitches in all organism that synthesise thiamine.

Thiamine is found in a wide variety of foods at low concentration.

·            Yeast extract and pork are the most highly concentrated sources of thiamine.

·            In general, cereal grains are the most important dietary sources of thiamine, by virtue of their ubiquity.

·            Some other foods rich in thiamine are oatmeal, flax, and sunflower seeds, brown rice, whole grain rye,

        asparagus, kale, cauliflower, potatoes, oranges, liver (beef, pork, and chicken), and eggs.

Reference Daily Intake and High Doses

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

  

Deficiency

·        Thiamine derivates and thiamine-dependent enzymes are present in all cells of the body, thus a thiamine deficiency would seem to adversely affect all of the organ system.

·       However, the nervous system and the heart are particularly sensitive to thiamine deficiency, because of  their high oxidative metabolism.

       Thiamine deficiency can lead to severe fatigue of eyes and 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 high in anti-thiamine factors ( tea, coffee, betel nuts)

·       grossly impaired nutritional status associated with chronic diseases, such as alcoholism, gastrointestinal diseases, HIV-AIDS and  persistent vomiting.

Beriberi

·            Beriberi is a neurological and cardiovascular disease.

·            Dry beriberi

·            Wet beriberi

·            Infantile beriberi

Alcoholic Brain Disease

·       Wernicke’s encephalopathy is the most frequently encountered manifestation of thiamine deficiency in Western society

·   Korsakoff Psychosis is  an amnestic-confabulatory syndrome characterized by retrograde and anterograde amnesia, impairment of conceptual functions, and decreased spontaneity and initiative.

Too Much of Thiamine

·            Doses higher than 100 mg may cause drowsiness or muscle relaxation.

·            Large doses (5,000 to 10,000mg) can cause headaches, irritability, rapid pulse, and weakness.

·            Stomach upset