What is vitamin B1? What are its therapeutic uses?

Overview

Vitamin B1, also called thiamin, was the first B vitamin discovered. Every cell in the 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 to keep up its constant work. Severe deficiency of thiamin results in beriberi, a disease common in the nineteenth century but rare today. Many of the principal symptoms of beriberi involve impaired heart function.

Requirements and Sources

The need for vitamin B1 varies with age and gender. The official U.S. and Canadian recommendations for daily intake are as follows:

Infants aged 0 to 6 months (0.2 mg) and 7 to 12 months (0.3 mg); children aged 1 to 3 years (0.5 mg), 4 to 8 years (0.6 mg), and 9 to 13 years (0.9 mg); males aged 14 years and older (1.2 mg); females aged 14 to 18 years (1.0 mg); women (1.1 mg); and pregnant or nursing women (1.4 mg).

Although vitamin B1 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 B1. Certain foods may impair the body’s absorption of B1, including fish, shrimp, clams, mussels, and the herb horsetail.

Brewer’s and nutritional yeast are the richest sources of B1. 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 milligrams (mg) daily, although much higher dosages have also been tried. Some nutritional experts recommend taking B1 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 B1. Since the heart depends on vitamin B1 for its proper function, this is potentially quite worrisome. Preliminary evidence, including a small double-blind, placebo-controlled trial, hints that supplementation with B1 can improve symptoms.

One double-blind study suggests that thiamin taken at a dose of 50 mg daily might enhance mental function. Other potential uses of thiamin have even less scientific support. Observational studies of people with human immunodeficiency virus (HIV) infection suggest–but definitely do not prove–that increased intake of vitamin B1 might slow progression to acquired immunodeficiency syndrome (AIDS) and enhance overall survival rate. Weak and contradictory evidence hints that vitamin B1 may be helpful for Alzheimer’s disease. Vitamin B1 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 B1 appears to be quite safe, even when taken in very high doses. People who are taking loop diuretics, such as furosemide or Lasix, may need extra vitamin B1.

Bibliography

Benton, D., et al. “Thiamine Supplementation, Mood and Cognitive Functioning.” Psychopharmacology (Berl) 129 (1997): 66-71.

Bettendorff, L., et al. “Low Thiamine Diphosphate Levels in Brains of Patients with Frontal Lobe Degeneration of the Non-Alzheimer’s Type.” Journal of Neurochemistry 69 (1997): 2005-2010.

Brady, J. A., C. L. Rock, and M. R. Horneffer. “Thiamin Status, Diuretic Medications, and the Management of Congestive Heart Failure.” Journal of the American Dietetic Association 95 (1995): 541-544.

Gold, M., R. A. Hauser, and M. F. Chen. “Plasma Thiamine Deficiency Associated with Alzheimer’s Disease but Not Parkinson’s Disease.” Metabolic Brain Disease 13 (1998): 43-53.

Mimori Y., H. Katsuoka, and S. Nakamura. “Thiamine Therapy in Alzheimer’s Disease.” Metabolic Brain Disease 11 (1996): 89-94.

Shimon, I., et al. “Improved Left Ventricular Function After Thiamine Supplementation in Patients with Congestive Heart Failure Receiving Long-Term Furosemide Therapy.” American Journal of Medicine 98 (1995): 485-490.