Vitamin B1

Figure 1. The chemical structure of Vitamin B1 (or Thiamine).

Vitamin B1 or Thiamine is a micronutrient and one of eight essential B vitamins. Vitamin B1 is soluble in water, methanol, and glycerol, and it can be degraded by exposure to heat. Within the body, the best-characterized form of Vitamin B1 is thiamine pyrophosphate (TPP), also called thiamine diphosphate, a coenzyme that catabolises sugars and amino acids. Vitamin B1 is involved in the breaking down of nutrients into energy, thus it is an essential vitamin for organs such as the brain and heart that require a constant supply of energy.

Apart from thiamine pyrophosphate (TPP), four other natural thiamine phosphate derivatives are known: thiamine monophosphate (ThMP), thiamine triphosphate (ThTP), adenosine thiamine triphosphate (AThTP) and adenosine thiamine diphosphate (AThDP). Thiamine phosphate derivatives are involved in many cellular processes. In the human body, only a small amount of Vitamin B1 is stored in the liver.

Food Sources

Vitamin B1 is found naturally in meats, fish, and whole grains. Common sources include:

• Fortified breakfast cereals
• Pork
• Fish
• Beans, lentils
• Green peas
• Sunflower seeds
• Yogurt
• Acorn squash
• Corn

Taken as a Dietary Supplement

As a dietary supplement, Vitamin B1 is often used to treat Vitamin B1 deficiency conditions. While rare, Vitamin B1 deficiency can occur due to a low intake of foods containing Thiamine, decreased absorption in the gut, or increased losses in urine such as with alcohol abuse or use of diuretics. Severe Vitamin B1 deficiency can lead to beriberi, which causes muscle loss and diminished feeling in the hands and feet (i.e. peripheral neuropathy), eventually leading to fluid build-up in the heart and lower limbs which can be fatal. Symptoms of mild to moderate Vitamin B1 deficiency include:

• Weight loss, loss of appetite
• Confusion, memory loss
• Muscle weakness
• Peripheral neuropathy
• Lowered immunity

The Recommended Dietary Allowance for Vitamin B1 for men ages 19 and older is 1.2mg daily, and for women in the same age range 1.1mg daily. For pregnancy and lactation, the amount increases to 1.4mg daily. Being a water soluble vitamin, Vitamin B1 is well tolerated in the human body thus unlikely to cause adverse side effects from high Vitamin B1 intake.

Background

Vitamin B1 (Thiamine) is listed in the World Health Organization's List of Essential Medicines.