Vitamin B1 (Thiamine or thiamin) supports the nervous system and mental attitude. Its odor and flavor are similar to yeast. Thiamine can be destroyed by the cooking process, especially by boiling or moist heat, but less by dry heat, such as baking.

Thiamine is essential for carbohydrate metabolism through its coenzyme functions. Coenzymes are "helper molecules" which activate enzymes, the proteins that control the thousands of biochemical processes occurring in the body. The thiamine-coenzyme, thiamine pyrophosphate or TPP, is the key for several reactions in the breakdown of glucose to energy. TPP acts as coenzyme in oxidative decarboxylation and transketolase reactions. Thiamine also plays a role in the conduction of nerve impulses and in aerobic metabolism. Older people absorb thiamine less efficiently.

Thiamine is lost in cooking and is depleted by use of sugar, coffee, tannin from black teas, nicotine, and alcohol, so it is necessary to insure that intake of thiamine is an optimal level.

Like other B vitamins, thiamine is needed in regularly. Excess thiamine is eliminated in the urine and sweat.

Thiamin is also a miraculous nutrient. Somebody suffering from beriberi, scarcely able to lift his/her head from the pillow, will respond quickly from injected thiamin. The person will be on his/her feet within a matter of hours.

Thiamin may enhance circulation, helps with blood formation and the metabolism of carbohydrates. It is also required for the health of the nervous system and is used in the biosynthesis of a number of cell constituents, including the neurotransmitter acetylcholine and gamma-aminobutyric acid (GABA). It is used in the manufacture of hydrochloric acid, and therefore plays a part in digestion.

It is also great for the brain and may help with depression and assist with memory and learning. In children it is required for growth and has shown some indication to assist in arthritis, cataracts, as well as infertility.

A deficiency will result in beriberi, and minor deficiencies may be indicated with extreme fatigue, irritability, constipation, edema and an enlarged liver. Forgetfulness, gastrointestinal disturbances, heart changes, irritability, labored breathing and loss of appetite may also be experienced. With too little thiamin around a person may also experience nervousness, numbness of the hands and feet, pain and sensitivity, poor coordination, tingling sensations, weak and sore muscles, general weakness and severe weight loss.

When taking alcohol, antacids and birth control pills or if you have hormone replacement therapy, you need to look at your thiamin intake. People suffering from depression or anxiety and those passing large volumes of urine, or suffering from an infection may all require more thiamine.

Sunflower seeds, peanuts, wheat bran, beef liver, pork, seafood, eggyolk and beans all contain good amounts of thiamin.

It is thought that thiamin can be useful for motion sickness in air and sea travel, and that this vitamin also repels insects when excreted through the skin.