Vitamin B-1, also called thiamine, is a nutrient with a critical role in maintaining a healthy central nervous system and controlling addictions. Adequate thiamine levels can dramatically affect mental functions by helping  maintain a sense of well being and by enhancing  learning abilities. Conversely, inadequate levels of B1 can lead to eye weakness, mental confusion, and loss of physical coordination.

Vitamin B1 is required for the production of hydrochloric acid, for forming blood cells, and for maintaining healthy circulation. It also plays a key role in converting carbohydrates into energy, and in maintaining good muscle tone of the digestive system and the heart.

Like all the B-vitamins, B-1 is a water soluble nutrient that cannot be stored in the body, but must be replenished on a daily basis. B-1 is also synergistic, meaning that it is most effective when taken in a balanced complex of the other B vitamins.

A chronic deficiency of thiamin will lead to a beriberi, a devastating and potentially deadly disease of the central nervous system. Due to improved diets and widespread use of inexpensive supplements, beriberi is extremely rare in the developed nations, with one important exception. Beriberi symptoms are frequently found in chronic alcoholics due to the destructive effect alcohol has on B1. Thiamine levels can also be affected by ingestion of antibiotics, sulfa drugs, caffeine, antacids, and oral contraceptives. A diet high in carbohydrates can also increase ones need for B1.

Food sources high in thiamine include dried beans, eggs, brewers yeast, whole grains, brown rice, and seafood. In supplemental form, B-1 is generally found in a combination with vitamins B-2, B-3, B-6, pantothenic acid, and folic acid. There are no known toxic effects from vitamin B-1, and any excess is simply excreted from the body. The Recommended Daily Amount for B-1 is 1.5 milligrams, though more typical daily intake ranges from 50 to 500 milligrams per day.