The first B vitamin to be discovered, vitamin B1 (thiamin) is part of an enzyme system essensational for nearly every cellular reaction in the body due to its involvement in energy production and carbohydrate and fatty acid metabolism.

Foods rich in thiamin include organ meats, dried beans, peas, soybeans, peanuts, poultry, egg yolks and fish.  Sources of moderate amounts include plums, raisins, asparagus, broccoli and oatmeal.  However, foods lose their thiamin content if exposed to ultraviolet light, sulfites, nitrites or live yeast.  Cooking also destroys a portion of the nutrients.

It has been suggested that adequate thiamin levels may help prevent the accumulation of fatty deposits in the arteries and thereby reduce the progression of atherosclerosis.  Thiamin also is important in the health of the nervous system, possibly because of its role in the synthesis ofacetylcholine, a neurotransmitter.

Thiamin deficiency is rare in developed countries because refined flours and cereals are often fortified with the nutrient.  But there are some risks for young children and teenagers, stressed adults, heavy exercises, alcoholics and pregnant women.  The classic deficiency disease is beriberi, which affects the gastrointestinal, cardiovascular and peripheral nervous systems.  One of the earthiest signs of thiamin deficiency is reduced stamina.  Depression, irritability and reduced ability to concentrate are later followed by fatigue, muscle cramps and various pains.  Advanced symptoms include indigestion, constipation, insomnia, and a heaviness in the legs.

The Reference Daily Intake (RDI) for thiamin is 1.5 mg for man and women, and 1.7 mg for pregnant and lactating women.  The Real Vitamin and Mineral Book by Shari Liberman, Ph.D., and Nancy Bruning, however recommendes 25 to 300 mg for men and women with optimal general health.

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