Vitamin B1, also called thiamin, was the first B vitamin discovered. Every cell in your body needs thiamin to make adenosine triphosphate, or ATP, the body's main energy-carrying molecule. The heart, in particular, has considerable need for thiamin in order to keep up its constant work. Severe deficiency of thiamin results in beriberi, a disease common in the 19th century, but rare today. Many of the principal symptoms of beriberi involve impaired heart function.



Your need for vitamin B 1 varies with age. The official US and Canadian recommendations for daily intake are as follows:

  • Infants
    • 0-6 months: 0.2 mg
    • 7-12 months: 0.3 mg
  • Children
    • 1-3 years: 0.5 mg
    • 4-8 years: 0.6 mg
    • 9-13 years: 0.9 mg
  • Males
    • 14 years and older: 1.2 mg
  • Females
    • 14-18 years: 1.0 mg
    • 19 years and older: 1.1 mg 
  • Pregnant or Nursing Women : 1.4 mg

Although vitamin B 1 deficiency is rare in the developed world, it may occur in certain medical conditions, such as alcoholism]]> , ]]>anorexia]]> , ]]>Crohn's disease]]> , and ]]>folate]]> deficiency. People undergoing kidney dialysis or taking ]]>loop diuretics]]> may also become deficient in vitamin B 1 . Certain foods may impair your body's absorption of B 1 as well, including fish, shrimp, clams, mussels, and the herb ]]>horsetail]]> .

Brewer's and nutritional yeast are the richest sources of B 1 . Peas, beans, nuts, seeds, and whole grains also provide fairly good amounts.


Therapeutic Dosages

A typical dose of vitamin B1 for therapeutic purposes is 200 mg daily, although much higher dosages have also been tried.

Some nutritional experts recommend taking B 1 with other B vitamins in the form of a B-complex]]> supplement. However, there is no meaningful evidence that this offers any advantage.


Therapeutic Uses

Congestive heart failure]]> (CHF) is a condition in which the pumping ability of the heart declines, and fluid begins to accumulate in the lungs and legs. Standard treatment for CHF includes strong "water pills" called ]]>loop diuretics]]> . These drugs, however, deplete the body of B 1 . ]]>1]]> Since the heart depends on vitamin B 1 for its proper function, this is potentially quite worrisome. Preliminary evidence, including a small ]]>double-blind placebo-controlled trial]]> , hints that supplementation with B 1 can improve symptoms. ]]>2,3]]>

One double-blind study suggests that thiamin taken at a dose of 50 mg daily might ]]>enhance mental function]]> . ]]>14]]>

Other potential uses of thiamin have even less scientific support. ]]>Observational studies]]> of people with ]]>HIV]]> infection suggest (but definitely do not prove) that increased intake of vitamin B 1 might slow progression to AIDS and enhance overall survival rate. ]]>4,5]]> Weak and contradictory evidence hints that vitamin B 1 may be helpful for ]]>Alzheimer's disease]]> . ]]>6-10]]> Vitamin B 1 has also been proposed as a treatment for ]]>epilepsy]]> , ]]>canker sores]]> , and ]]>fibromyalgia]]> , but the evidence for these uses is too preliminary to cite.


Safety Issues

Vitamin B 1 appears to be quite safe even when taken in very high doses.

Interactions You Should Know About

If you are taking: