B1, most commonly taken within a B-complex, is necessary for energy production, nerve health, and mental function, including focus and memory, in addition to having antioxidant capabilities, protecting cells from free radicals. B1 may also have mild diuretic effects.
Vitamin B1 can be found in whole grains, oatmeal, and nuts; Brewer’s yeast and black strap molasses; and in meat, poultry, and fish.
Note : Vitamin B1 is destroyed when foods are cooked. In addition, Vitamin B1 levels in the body are depleted with the use of sugar, tannins (found in tea and coffee), nicotine, high-carb diets, and alcohol.
Popup: Foods highest in Thiamin
The Daily Value for Thiamin is 1.5 mg.
When taken with the other B vitamins, B1 may increase energy levels, relieving post-exercise fatigue while improving reaction time, mental focus, and attitude. Also necessary for optimal health of muscle tissue, cardiovascular function, and the nervous system, the B vitamins are important for overall health. B1 by itself may also cause slight diuretic effects.
Deficiency of Thiamin has been linked to:
Research indicates that Thiamin may also be useful in the treatment of:
The first B vitamin discovered (explaining the name B1), thiamin is found in our muscles, heart, liver, kidneys, and brains and is important for virtually every cellular reaction. It’s necessary for energy production because of its role in helping break down carbohydrates and fats, so their “energy” is released for our cells to use, as well as helping form ATP. But it’s perhaps most important for the health and functioning of our nerves because it’s needed for the body to make the chemical messenger acetylcholine, which is vital for memory as well as the muscle tone of specific organs.
Like many of the other B vitamins, thiamin has a reputation for increasing energy levels. Specifically for athletes, thiamin has been shown to help reduce fatigue that’s been caused by intense exercise. One study performed in Japan showed that 100 mg of thiamin helped reduce changes in blood sugar and reduce fatigue after exercise.
Another study showed that thiamin may also help improve mental functioning even in people who aren’t deficient. This study, performed in Wales, showed that women who supplemented with 50 mg of thiamin felt more energetic and clearheaded. What’s more, their reaction times improved.
Thiamin is also an antioxidant and is believed by some experts to help protect the body from aging, alcohol, and cigarette smoke. Plus, it’s important for circulation and blood formation. It’s also needed to help produce hydrochloric acid, which is necessary for digestion.
While found in many foods, thiamin is easily destroyed by cooking and processing, so the foods Americans typically eat often have lost this nutrient. Many of us compound that loss with high intakes of sugar and/or coffee — two compounds that further deplete the body. Thus, to help protect us from deficiencies that could lead to a condition called “beriberi,” thiamin has been added (fortified) to white flour, bread, and cereal, which most of us consume on a daily basis. So a severe deficiency of this vitamin is now rare in developed countries.
Nonetheless, there are groups of people that are still at risk for at least marginal deficiencies, including people who exercise intensely, folks who are dealing with high amounts of stress, teenagers who eat lots of empty calories, people on high-carbohydrate diets, and the elderly. Alcoholics are by far at the greatest risk for deficiencies.
Along with marginal deficiencies come lack of stamina (one of the first symptoms), potentially followed by irritability and inability to concentrate, pain, fatigue, and muscle cramps. Other symptoms include stiffness, nausea, and weight loss. Permanent damage to the nervous system can occur as the deficiencies get more severe.
Because of thiamin’s key role in nervous-system functioning, energy production, and its effects on attitude and mental status, thiamin is often called the “morale vitamin.” Regardless of what it’s called, these functions are essential for optimal performance, in all aspects of life, once again revealing the potential benefits of supplementing with a B-complex.
Many experts recommend 50 to 100 mg of thiamin per day. The minimum amount recommended is typically between 2 and 8 mg per day.
Some experts suggest that Vitamin B1 needs depend more on the amount of food eaten on a daily basis and thus recommend 0.5 mg per 1,000 calories consumed.
Like other B vitamins, thiamin is typically recommended divided throughout the day as part of a B-complex supplement.
Antibiotics, sulfa drugs, and oral contraceptives decrease the levels of B1 in the body. Digoxin, indomethacin, anticonvulsants, antacids, and diuretics may also reduce the absorption of thiamin, which may lead to deficiencies.
No known toxicity.