Like most other B vitamins, thiamine is needed in regular supply, though after its absorption from the upper and lower small intestine, some B1 is stored in the liver, heart, and kidneys. Most excess thiamine is eliminated in the urine; some seems to be excreted in the sweat as well.

Sources: Since thiamine is lost in cooking and is depleted by use of sugar, coffee, tannin from black teas, nicotine, and alcohol, it is necessary to insure that intake of thiamine is optimal. There are a number of food sources for thiamine; however, they may not be the everyday fare for many people. Good sources of vitamin B1 include the germ and bran of wheat, rice husks (outer covering), and the outer portion of other grains. With the milling of grains and use of refined flours and white or "polished" rice, many of us are no longer getting the nourishment of thiamine that is available when we eat wholesome, unprocessed foods.

Other good sources of thiamine besides wheat germ and bran, whole wheat or enriched wheat flour, and brown rice are brewer's yeast and blackstrap molasses. Oats and millet have modest amounts, as do many vegetables, such as spinach and cauliflower, most nuts, sunflower seeds, and legumes, such as peanuts, peas, and beans. Of the fruits, avocado is the highest in vitamin B1. Pork has a high amount of this B vitamin. Many dried fruits contain some thiamine, though the sulfur dioxide often added as a preservative seems to destroy this vitamin.

Functions: Thiamine helps a great many bodily functions, acting as the coenzyme thiamine pyrophosphate (TPP). It has a key metabolic role in the cellular production of energy, mainly in glucose metabolism. Thiamine is also needed to metabolize ethanol, converting it to carbon dioxide and water. B1 helps in the initial steps of fatty acid and sterol production. In this way, thiamine also helps convert carbohydrate to fat for storage of potential energy.

Thiamine is important to the health of the nerves and nervous system, possibly because of its role in the synthesis of acetylcholine (via the production of acetyl CoA), an important neurotransmitter. With a lack of vitamin B1, the nerves are more sensitive to inflammation. Thiamine is linked to individual learning capacity and to growth in children. It is also important to the muscle tone of the stomach, intestines, and heart because of the function of acetylcholine at nerve synaptic junction. It is conceivable that adequate thiamine levels may help prevent the accumulation of fatty deposits in the arteries and thereby reduce the progression of atherosclerosis.

Uses: Vitamin B1 is, of course, used to treat any of the symptoms of its deficiency or its deficiency disease beriberi (discussed below). It is used in the treatment of fatigue, irritability, low morale, and depression and to prevent air- or seasickness. It seems to help the nerves, heart, and muscular system function well. By aiding hydrochloric acid production, thiamine may help digestion or reduce nausea, and it can remedy constipation by increasing intestinal muscle tone. Thiamine is used commonly to improve healing after dental (or, often, any) surgery.