Thiamine

Thiamine, also known as thiamin or vitamin B1, is a vitamin found in food, and manufactured as a dietary supplement and medication. It is a nutrient that is not synthesized in the human body. Food sources of thiamine include whole grains, legumes, and some meats and fish. Grain processing removes much of the thiamine content, so in many countries cereals and flours are enriched with thiamine. Thiamine is a building block required for energy production and glucose metabolism. Supplements and medications are available to treat and prevent thiamine deficiency and disorders that result from it, including beriberi and Wernicke encephalopathy. Other uses include the treatment of maple syrup urine disease and Leigh syndrome. They are typically taken by mouth, but may also be given by intravenous or intramuscular injection. Thiamine supplements are generally well tolerated. Allergic reactions, including anaphylaxis, may occur when repeated doses are given by injection. Thiamine is in the B complex family. It is an essential micronutrient, which cannot be made in the body. Thiamine is required for metabolism including that of glucose, amino acids, and lipids. Thiamine was discovered in 1897, was the first vitamin to be isolated in 1926, and was first made in 1936. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. Thiamine is available as a generic medication, and as an over-the-counter drug. The wholesale cost in the developing world (as of 2016) is about US$2.17 per one gm vial. In the United States a month's supply of a multivitamin containing thiamine is less than US$25. Thiamine is used to treat thiamine deficiency which when severe can prove fatal. In less severe cases, non-specific signs include malaise, weight loss, irritability and confusion. Well-known disorders caused by thiamine deficiency include beriberi, Wernicke-Korsakoff syndrome, optic neuropathy, Leigh's disease, African Seasonal Ataxia, and central pontine myelinolysis. In Western countries, thiamine deficiency is seen mainly in chronic alcoholism. Thiamine deficiency is often present in alcohol misuse disorder. Also at risk are older adults, persons with HIV/AIDS or diabetes, and persons who have had bariatric surgery. Varying degrees of thiamine deficiency have been associated with the long-term use of high doses of diuretics, particularly furosemide in the treatment of heart failure. Women who are pregnant or lactating require more thiamine. In pregnancy, this increased is likely due to thiamine being preferentially sent to the fetus and placenta, especially during the third trimester. Pregnant women with hyperemesis gravidarum are also at an increased risk for thiamine deficiency due to losses when vomiting. For lactating women, thiamine is delivered in breast milk even if it results in thiamine deficiency in the mother. Thiamine is an important aspect for not only mitochondrial membrane development, but also synaptosomal membrane function. It has also been suggested that thiamine deficiency plays a role in the poor development of the infant brain that can lead to sudden infant death syndrome (SIDS).