Overview
Vitamin B1, also called thiamine, is one of eight B vitamins. All B vitamins help the body convert carbohydrates into fuel (glucose), which is used to produce energy. These B vitamins, often referred to as B complex vitamins, also help the body metabolize fats and protein. B complex vitamins are needed for healthy skin, hair, eyes, and liver. They also help the nervous system function properly, and are needed for good brain function. All B vitamins are water-soluble, meaning that the body does not store them and must be replenished daily.
Like other B complex vitamins, thiamine is sometimes called an “anti-stress” vitamin because it strengthens the immune system and improves the body’s ability to withstand stressful conditions. It is named B1 because it was the first B vitamin discovered.
Thiamine is found in both plants and animals and plays a crucial role in certain metabolic reactions. Your body needs it to form adenosine triphosphate (ATP), which every cell of the body uses for energy.
It’s rare to be severely deficient in thiamine, although alcoholics, people with Crohn’s disease, anorexia, and those undergoing kidney dialysis may be deficient. Thiamine deficiency may result from dependence on unfortified, polished rice as the staple food
and from the consumption of a diet that is limiting in other respects. Symptoms of thiamine deficiency are fatigue, irritability, depression and abdominal discomfort. People with thiamine deficiency also have trouble digesting carbohydrates. That allows a substance called pyruvic acid to build up in their bloodstream, causing a loss of mental alertness, difficulty breathing, and heart damage, a disease known as beriberi.
Beriberi
The most important use of thiamine is to treat beriberi, which is caused by not getting enough thiamine in your diet. Symptoms include swelling, tingling, or burning sensation in the hands and feet, confusion, trouble breathing because of fluid in the lungs, and uncontrolled eye movements called nystagmus. People in the developed world usually don’t get beriberi.
Dietary Sources
Large amounts can be found in pork and organ meats. Other good dietary sources of thiamine include whole-grain or enriched cereals and rice, legumes, wheat germ, bran, brewer’s yeast, and blackstrap molasses.
Safety and limits
The Council for Responsible Nutrition considers 100 mg of supplemental Thiamine to be the safe upper limit, although studies suggest that much higher doses (6,000 mg daily) are safe.
Sources
University of Maryland Medical Center