General Description
Thiamin (also spelled thiamine) is a water-soluble vitamin required
by every tissue in the body. First isolated in 1926, thiamin was
the first B-vitamin to be discovered, which is why it is also known
as vitamin B-1. It is involved in numerous enzymatic processes relating
to energy production, carbohydrate metabolism, and nerve cell function.
Most of the thiamin in the body is bonded to phosphate molecules
(phosphorylated) to form energy-storing compounds such as thiamin
monophosphate, thiamin diphosphate, and thiamin triphosphate. The
energy potential of these compounds depends on the number of phosphate
molecules they contain; thiamin triphosphate has high energy potential,
while thiamin diphosphate has less, and thiamin monophosphate has
the least. Each of these forms serves different functions in the
body. Unphosphylated (a.k.a. "free") thiamin does not appear to
be biologically active. Supplemental thiamin (as found in multi-vitamin
and B-complex formulas) is usually in the form of thiamin salts
such as thiamin hydrochloride or thiamine mononitrate.
Food sources
Thiamin is found in a wide variety of foods. Among the best sources
are organ meats (especially liver), brewer's yeast, whole grains,
nuts, peanuts, and sunflower seeds. Other sources of thiamin include
meat, egg yolks, poultry, fish, plums, prunes, raisins, broccoli,
Brussels sprouts, and fortified flour. Foods may lose much of
their thiamin content through cooking or exposure to ultraviolet
light, nitrites, sulfites, or live yeast. Thiamin is also destroyed
by alcohol, enzymes found in raw seafood, and tannins found in
coffee and tea.
Health applications
- Energy metabolism
- Mental function
- Alcoholism
- Diabetes
- Crohn's disease
- Multiple sclerosis
Functions and uses
The phosphorylated forms of thiamin serve as cofactors in numerous
enzymatic processes in the body, most notably those involved in
energy metabolism and in brain and nerve cell function. Because
thiamin is essential for the conversion of carbohydrates into energy,
high carbohydrate intake increases the body's thiamin requirements.
Thiamin requirements also increase during times of elevated metabolism
such as fever, pregnancy, lactation, and physical or emotional stress.
Severe thiamin deficiency results in beriberi (Singhalese for "I
can not," reflecting the debilitating nature of the disease), a
condition marked by psychological illness, heart failure, nerve
paralysis, and muscular deterioration. Chronic thiamin deficiency
results in Wernicke-Korsakoff syndrome, a serious brain disorder
marked by memory loss, disorientation, a staggering gait, and eventually,
psychosis and death. In economically developed nations where malnutrition
is rare, thiamin deficiency is most often seen in alcoholics and
people with malabsorption disorders such as Crohn's disease.1-3
Other disorders in which thiamin supplementation may be beneficial
include multiple sclerosis,4,5 Alzheimer's disease,6-8
and diabetes.9 Dosage/toxicity
The reference daily intake (RDI) for thaimin is 1.5 mg per day.
Because thiamin is found in a wide variety of foods, most people
receive this amount through dietary intake. As a water-soluble
vitamin, thiamin is not stored in the body, and must be consumed
daily. Thiamin has no known toxicity, even at very high doses.
Excess thiamin is excreted in the urine.
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