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Vitamin B1 (Thiamine)

Vitamin B1 is also called thiamine. You need vitamin B1 in your daily diet to help break down carbohydrates (starches). The energy produced by this process helps your body perform functions as basic as breathing and moving. Not getting enough vitamin B1 in your daily diet leads to a disease called beri beri, which can affect your nervous system and heart. Alcoholics are at a high risk of developing beri beri because prolonged intake of large amounts of alcohol depletes your body's supply of vitamin B1.


The most important use of vitamin B1 is to improve symptoms of beri beri. These symptoms include nervous system symptoms such as pain, swelling, and redness of the hands and feet, and a tickling or burning sensation in the hands and feet. Confusion and loss of memory are also potential symptoms.

Other symptoms of beri beri include difficulty in breathing, swelling of the legs, and rapid heart beat. Certain diuretics may cause you to lose Vitamin B1 through urination, causing a deficiency.

Recent research suggests that vitamin B1 may help manage congestive heart failure.

Vitamin B1 may also play a negative role in cancer chemotherapy. Researchers have found that taking too much vitamin B1 while undergoing chemotherapy may make tumors grow more quickly.

Dietary Sources

Cereals and pork are excellent sources of vitamin B1. Other good sources of vitamin B1 are white enriched rice, sunflower seeds, peanuts, wheat germ, brewer's yeast, soy milk, beans, and pasta.

Milk, fruits, and vegetables are also good sources of vitamin B1 if consumed in adequate amounts.

Other Forms

Vitamin B1 is labeled as thiamine hydrochloride and thiamine mononitrate. It is available as tablets or capsules in multivitamin form, including children's chewable and liquid forms, B-complex form, or by itself.

How to Take It

To avoid diseases of vitamin B1 deficiency, adults should take between 1.1 mg and 1.5 mg of vitamin B1 daily with water, preferably after eating. Pregnant women should take 1.5 mg daily, and women who are breast-feeding should take 1.6 mg of vitamin B1 daily. As with all medications and supplements, check with a health care provider before giving vitamin B1 supplements to a child. If you are pregnant, discuss taking vitamin B1 with your health care provider before you begin taking it.


Vitamin B1 is generally nontoxic. Stomach upset can occur at very high doses (much higher than the recommended daily doses).

Possible Interactions

Diuretics, particularly furosemide, may reduce the levels of thiamine.

In addition, furosemide and digoxin, particularly when taken together for long periods of time, may interfere with the ability of thiamine to benefit the heart.

Supporting Research

Boros LG, Brandes JL, Lee W-N P, et al. Thiamine supplementation to cancer patients: a double-edged sword. Anticancer Res. 1998;18:595602.

Ekhard ZE, Filer LJ, eds. Present Knowledge in Nutrition. 7th ed. Washington, DC: ILIS Press; 1996:160166.

Hardman JG, Limbird LE, eds. Goodman and Gilman's The Pharmacological Basis of Therapeutics. 9th ed. New York, NY: McGraw-Hill; 1996:15551558.

Leslie D, Gheorghiade M. Is there a role for thiamine supplementation in the management of heart failure? Am Heart J. 1996;131:12481250.

Lindberg MC, Oyler RA. Wernick's encephalopathy. Am Fam Physician. 1990;41:12051209.

Lubetsky A, Winaver J, Seligmann H, et al. Urinary thiamine excretion in the rat: effects of furosemide, other diuretics, and volume load [see comments]. J Lab Clin Med. 1999;134(3):232-237.

Mahan LK, Arlin MT, eds. Krause's Food, Nutrition and Diet Therapy. 8th ed. Philadelphia, Pa: WB Saunders;1992:8587.

Mason P. Nutrition and Dietary Advice in the Pharmacy. Oxford, UK: Blackwell Scientific; 1994:269271.

National Academy of Science. Recommended Daily Allowances. Accessed at on January 4, 1999.

Rieck J, Halkin H, Almog S, et al. Urinary loss of thiamine is increased by low doses of furosemide in healthy volunteers. J Lab Clin Med. 1999;134(3):238-243.

Zangen A, Botzer D, Zanger R, Shainberg A. Furosemide and digoxin inhibit thiamine uptake in cardiac cells. Eur J Pharmacol. 1998;361(1):151-155.

Copyright 2000 Integrative Medicine Communications

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