Vitamin B1, also known as thiamine, is a water-soluble vitamin that plays an important role in energy metabolism. It helps your body convert carbohydrates into energy that your cells can use, and is essential for the healthy functioning of your nervous system and muscles. Thiamine also helps synthesize neurotransmitters important for brain function, including acetylcholine and gamma-aminobutyric acid (GABA).
Thiamine is found in a variety of foods, including whole grains, meat, fish, beans, and nuts. Deficiency in vitamin B1 can lead to a condition called beriberi, which can cause symptoms such as fatigue, weakness, nerve damage, and even heart failure. In severe cases, untreated deficiency can be life-threatening. However, vitamin B1 deficiency is rare in developed countries, as many foods are fortified with this essential vitamin.