Vitamin B1, also known as thiamine, is essential in maintaining immune and neurological health, as well as proper functioning of the nervous system, according to MayoClinic. There are many dietary sources of thiamine, including grains, legumes, milk and nuts, says WebMD. Thiamine supplementation may be necessary for some people.
Very little thiamine is stored in the body and thiamine deficiency can lead to serious complications, claims MayoClinic. Thiamine deficiency is associated with the development of anemia, kidney dysfunction and heart failure, among other conditions. Thiamine supplements are often used in the treatment of metabolic disorders, most commonly alcoholism, since the vitamin is essential to proper digestion, carbohydrate metabolism and electrolyte flow.