Thiamin (also spelled "thiamine") is a water-soluble B-complex vitamin, previously known as vitamin B1 or aneurine. Thiamin was isolated and characterized in the 1920s, and thus was one of the first organic compounds to be recognized as a vitamin.

Thiamin is involved in numerous body functions, including: nervous system and muscle functioning; flow of electrolytes in and out of nerve and muscle cells (through ion channels); multiple enzyme processes (via the coenzyme thiamin pyrophosphate); carbohydrate metabolism; and production of hydrochloric acid (which is necessary for proper digestion). Because there is very little thiamin stored in the body, depletion can occur as quickly as within 14 days.

Thiamin deficiency (beriberi): Severe chronic thiamin deficiency can result in potentially serious complications involving the nervous system/brain, muscles, heart, and gastrointestinal system. Consequences of thiamin deficiency were described as early as 2600 B.C. in Chinese texts, and have been labeled historically with the term "beriberi." Beriberi has been divided into three subtypes: dry beriberi refers to neuromuscular complications such as peripheral neuropathy and weakness; wet beriberi refers to cardiovascular complications such as heart failure (Shoshin-type beriberi); and cerebral beriberi refers to central nervous system (brain) complications such as Wernicke's encephalopathy (abnormal eye movements, stance/gait abnormalities, mental dysfunction) or Korsakoff's psychosis (apathy, confusion, severe memory deficits/amnesia). Thiamin deficiency may result from inadequate thiamin intake, an increased requirement for thiamin, excessive loss of thiamin from the body, or consumption of anti-thiamin factors in food. People at particular risk for thiamin deficiency include chronic alcoholics, patients receiving intravenous feeding (total parenteral nutrition/TPN) for more than 7 days without multivitamins or dietary thiamin, or those on kidney dialysis.

Chronic alcoholism: In alcoholic or chronically malnourished patients, thiamin should always be administered before intravenous glucose solutions in order to avoid causing Wernicke's encephalopathy. All patients treated for alcohol withdrawal should be administered intravenous thiamin.

Synonyms

Aneurine HCL, aneurine mononitrate, antiberiberi factor, antiberiberi vitamin, antineuritic factor, antineuritic vitamin, anurine, B complex vitamin, beta-hydroxy-ethylthiazolium chloride, thiamin chloride, thiamin diphosphate, thiamin HCL, thiamin hydrochloride, thiamin monophosphate (TMP), thiamin nitrate, thiamin, thiamin pyrophosphate (TPP), thiamin triphosphate (TTP), thiamine chloride, thiaminium chloride HCL, thiaminium chloride hydrochloride.

Combination products: Thiamin is frequently used in combination with other B vitamins in vitamin B complex formulations. Vitamin B complexes generally also include vitamin B2 (riboflavin), vitamin B3 (niacin/niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do not contain all of these vitamins, and may include others such as biotin, para-aminobenzoic acid (PABA), choline bitartrate, and inositol. Refer to the manufacturer's label for details.

Evidence

These uses have been tested in humans or animals. Safety and effectiveness have not always been proven. Some of these conditions are potentially serious, and should be evaluated by a qualified healthcare provider.

Uses based on scientific evidence

Thiamin deficiency (Beriberi, Wernicke's encephalopathy, Korsakoff's psychosis, Wernicke-Korsakoff syndrome)

Humans are dependent on dietary intake to fulfill their thiamin requirements. Because there is very little thiamin stored in the body, depletion can occur as quickly as within 14 days. Severe chronic thiamin deficiency can result in potentially serious complications involving the nervous system/brain, muscles, heart, and gastrointestinal system.Causes: Thiamin deficiency can result from inadequate thiamin intake (for example in chronic alcoholics, patients receiving intravenous feeding/parenteral nutrition for more than 7 days without multivitamins or dietary thiamin, or those living in countries with principally carbohydrate-based diets); increased body requirements for thiamin (such as with strenuous exercise, malaria, HIV infection, hyperthyroidism, fever, severe liver disease, pregnancy, breastfeeding, or adolescent growth); excessive loss of thiamin from the body (for example in patients with kidney failure on dialysis or those taking diuretics); or consumption of large amounts of anti-thiamin factors in foods (such as coffee, tea, betel nuts, vitamin C, raw freshwater fish, shellfish, ferns, or African silkworms).Effects: Severe chronic thiamin deficiency can result in potentially serious complications involving the nervous system/brain, muscles, heart, and gastrointestinal system.Historically, the consequences of thiamin deficiency have been classified into three subtypes: 1) dry beriberi refers to neuromuscular complications such as peripheral neuropathy and weakness (including burning feet, exaggerated reflexes, diminished sensation and weakness in the legs and arms, muscle pains, and ultimately seizures in severe cases); 2) wet beriberi refers to cardiovascular complications such as rapid heart rate, pulmonary edema (water in the lungs), and heart failure/cardiomyopathy (Shoshin-type beriberi); and 3) cerebral beriberi refers to central nervous system (brain) complications such as Wernicke's encephalopathy (abnormal eye movements, stance/gait abnormalities, mental dysfunction), Korsakoff's psychosis (apathy, confusion, severe memory deficits/amnesia), or the combination of the two (Wernicke-Korsakoff syndrome).Treatment: Patients diagnosed with Wernicke's encephalopathy, Korsakoff's psychosis, or Wernicke-Korsakoff syndrome should be treated immediately with intravenous thiamin. Therapy usually improves eye symptoms, but may not improve memory deficits or motor coordination, depending on the duration or severity of the thiamin deficiency. Lack of treatment may result in permanent neurologic damage or death. Thiamin supplementation should be considered in chronic alcoholics, and all patients treated for alcohol withdrawal should be administered intravenous thiamin. Thiamin should always be administered before intravenous glucose solutions in alcoholic or chronically malnourished patients, in order to avoid causing Wernicke's encephalopathy. It is not clear that thiamin is beneficial to reverse cardiovascular complications (wet beriberi), although thiamin supplementation may arrest the progression of heart damage. If heart failure is present, standard medical therapy for this condition should be administered.

Metabolic disorders (Subacute necrotizing encephalopathy, Maple syrup urine disease, Pyruvate carboxylase deficiency, Hyperalaninemia)

Taking thiamin orally helps to temporarily correct some complications of metabolic disorders associated with genetic diseases including subacute necrotizing encephalopathy (SNE, Leigh's disease), maple syrup urine disease (branched-chain aminoacidopathy), and lactic acidosis associated with pyruvate carboxylase deficiency and hyperalaninemia. Long-term management should be under strict medical supervision.

Acute alcohol withdrawal

Patients with chronic alcoholism or experiencing alcohol withdrawal are at risk of thiamin deficiency and its associated complications, and should be administered thiamin. Thiamin should always be administered before intravenous glucose solutions in alcoholic or chronically malnourished patients (for example, 100mg IM or IV), in order to avoid causing Wernicke's encephalopathy.

Tags: Vitamins

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