Thiamin was the first B-vitamin discovered. Thiamin is important in a number of energy producing metabolic pathways within the body. As a part of TPP (thiamin pyrophosphate), thiamin plays a role in the breakdown of glucose for energy. When thiamin is inadequate, the body’s ability to metabolize carbohydrate is diminished. Another primary role for TPP is to act as a coenzyme in the metabolism of the branched chain amino acids. The highest concentrations of branched chain amino acids are found in the muscle, so these amino acids provide fuel for working the muscle especially during intense exercise. TPP also assists in the production of DNA and RNA which is important for cell regeneration and protein synthesis.
The RDA for thiamin for adults aged 19 years or older is 1.2 mg/day for men and 1.1 mg/day for women. It appears that the average adult in the US gets adequate amounts of thiamin in the diet. Those who are at risk for a thiamin deficiency are the elderly, who typically have reduced total energy intakes, and anyone with malabsorption syndrome or on renal dialysis because thiamin is cleared by the kidney. Also, people who eat a diet high in unenriched processed grains may be at risk for poor thiamin. Physically active individuals may also be at risk for thiamin deficiency. Depletion of B-vitamins, such as thiamin can reduce ability to perform physical activity.
Thiamin is found abundantly in ham and other pork products. Sunflower seeds, brans, oat bran, mixed dishes containing whole or enriched grains and meat, tuna fish, soy milk, and soy based meat substitutes are also good sources. Enriched and whole grain foods, including fortified ready-to-eat cereals, are rich in several B vitamins including thiamin.
As B-vitamins are involved in most energy generating processes, the deficiency symptoms include a combination of fatigue, apathy, muscle weakness, and reduced cognitive function. Thiamin deficiency is called beriberi. In this disease, the body’s inability to metabolize energy leads to muscle wasting and nerve damage and in later stages, the patient may be unable to move at all. The heart muscle may also be affected, and the patient may die of heart failure. Beriberi is seen in countries where unenriched, processed grains are a primary food source. Thiamin deficiency is also seen in industrialized countries in people with chronic heavy alcohol consumption and limited food intake. The alcohol related thiamin deficiency is called Wernicke-Korsakoff syndrome. High alcohol intake contributes to thiamin deficiency because it increases the need for thiamin to metabolize the alcohol and reduces the thiamin absorption.
Source: Thompson, Janice, Melinda Manore, and Linda A. Vaughan. The Science of Nutrition. San Francisco, CA: Pearson Benjamin Cummings, 2011. Print.