Vitamin B1, thiamin, or thiamine, enables the body to use carbohydrates as energy. It is essential for glucose metabolism, and it plays a key role in nerve, muscle, and heart function.

Vitamin B1 is a water-soluble vitamin, as are all vitamins of the B complex.

Vitamins are classified according to the materials they dissolve in. Some dissolve in water, and others dissolve in fat. Water-soluble vitamins are carried through the bloodstream. Whatever the body does not use is eliminated in urine.

Foods

Meat, fish, and grains are a good source of Vitamin B1

There are high concentrations of Vitamin B1 in the outer layers and germ of cereals, as well as in yeast, beef, pork, nuts, whole grains, and pulses.

Fruit and vegetables that contain it include cauliflower, liver, oranges, eggs, potatoes, asparagus, and kale.

Other sources include brewer’s yeast and blackstrap molasses.

Breakfast cereals and products made with white flour or white rice may be enriched with vitamin B.

In the United States, people consume around half of their vitamin B1 intake in foods that naturally contain thiamin, while the rest comes from foods that are fortified with the vitamin.

Heating, cooking, and processing foods, and boiling them in water, destroy thiamin. As vitamin B1 is water-soluble, it dissolves into cooking water. White rice that is not enriched will contain only one tenth of the thiamin available in brown rice.

The National Institutes of Health (NIH) Office of Dietary Supplements (ODS) note that one serving of fortified breakfast cereal provides 1.5 milligrams (mg) of thiamin, which is more than 100 percent of the daily recommended amount.

One slice of whole wheat bread contains 0.1 mg, or 7 percent of the daily requirement. Cheese, chicken, and apples contain no thiamin.

Humans need a continuous supply of vitamin B1, because it is not stored in the body. It should be part of the daily diet.