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.

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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.

Vitamin B1, or thiamin, helps prevent complications in the nervous system, brain, muscles, heart, stomach, and intestines. It is also involved in the flow of electrolytes into and out of muscle and nerve cells.

It helps prevent diseases such as beriberi, which involves disorders of the heart, nerves, and digestive system.

Uses in medicine

Patients who may receive thiamin to treat low levels of vitamin B1 include those with peripheral neuritis, which is an inflammation of the nerves outside the brain, or pellagra.

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Some athletes take thiamin supplements to boost their performance.

People with ulcerative colitis, persistent diarrhea, and poor appetite may also receive thiamin. Those who are in a coma may be given thiamin injections.

Some athletes use thiamin to help improve their performance. It is not a prohibited substances for athletes in the U.S.

Other conditions in which thiamin supplements may help include:

Not all of these uses have been definitively confirmed by research.

A deficiency of vitamin B1 commonly leads to beriberi, a condition that features problems with the peripheral nerves and wasting.

Weight loss and anorexia can develop.

There may be mental problems, including confusion and short-term memory loss.

Muscles may become weak, and cardiovascular symptoms can occur, for example, an enlarged heart.

How much vitamin B1 do we need?

In the U.S., the recommended daily allowance (RDA) of thiamin taken by mouth is 1.2 mg for males and 1.1 mg for females over the age of 18 years. Pregnant or breastfeeding women of any age should consume 1.4 mg each day.

Who is at risk of B1 deficiency?

People with poor diet, cancer, "morning sickness" during pregnancy, bariatric surgery, and hemodialysis are at risk of thiamin deficiency.

People who regularly drink alcohol to excess may have a deficiency, as they may not absorb thiamin from their food.

Wernicke-Korsakoff syndrome is a disorder that affects people with chronic alcoholism. It is linked to a lack of thiamin, and it can be fatal if not treated.

People with Wernicke-Korsakoff syndrome and those who are withdrawing from alcohol may receive thiamin injections to help them recover.

Other diseases, such as HIV, can reduce the absorption of nutrients, and this can lead to a deficiency of vitamin B1.

All B vitamins are water-soluble. They help to convert carbohydrates, fats, and protein into energy, or glucose.

B vitamins are necessary for keeping the liver, skin, hair, and eyes healthy. They also play a role in the nervous system, and they are needed for good brain function.

The B vitamins are sometimes called anti-stress vitamins, because they boost the body's immune system in times of stress.

Evidence does not confirm any harm from too much vitamin B1, but the U.S. Food and Drug Administration (FDA) warns on the use of supplements.

They urge people to check with their health care provider before using supplements with or as a substitute for foods, and they call on the public to seek a physician's advice on how to improve their health, rather than self-diagnosing.

Interactions

Tea and coffee contain tannins, chemicals that may interact with thiamin, making it harder to absorb.

Some of the chemicals in raw shellfish and fish can destroy thiamin, potentially leading to a deficiency if eaten in large quantities. Cooking destroys these chemicals, but it destroys thiamin too.