Vitamin B1, also known as thiamine, is a water-soluble vitamin that plays a key role in the metabolism of carbohydrates, helping to convert them into energy that the body can use. Thiamine also helps to maintain proper nervous system function and promotes healthy skin, hair, and eyes. Thiamine is an essential nutrient that cannot be produced by the body and must be obtained through the diet. Good dietary sources of thiamine include whole grains, legumes, pork, nuts, and seeds. Severe thiamine deficiency can lead to a condition known as beriberi, which can cause nerve damage, muscle weakness, and even heart failure. Supplementation with thiamine is often used to treat or prevent thiamine deficiency, particularly in people who have difficulty absorbing nutrients from their food or who consume large amounts of alcohol.