What are the symptoms of thiamine (vitamin B1) deficiency?

Elizabeth Casparro, MPH,RD
Nutrition & Dietetics
In the average person, thiamine (vitamin B1) deficiency can lead to a disease called beriberi. This can occur within 7 cans of a thiamin deficient diet. There are 2 main forms of beriberi: wet and dry. Both types cause peripheral neuropathy (numbness and tingling of the hands and feet). Dry beriberi also has the symptoms of weakness, nerve degeneration, irritability, poor arm/leg coordination, and loss of nerve transmission. Wet beriberi has the signs of edema, enlarged heart and heart failure, and occurs in more wet, humid climates.

Thiamin deficiency in alcoholics leads to a disease called Wernicke-Korsakoff syndrome/encephalopathy, which leads to many symptoms and signs which mimick drunkenness. These include double vision, staggering, poor muscle coordination, and mental confusion.

Thiamin deficiency can be prevented by eating good food sources. These include pork, cold cereal, legumes, enriched and whole grains, and luncheon meats.
Symptoms of thiamine deficiency, or a lack of vitamin B1, include fatigue, irritability, depression and stomach problems.

Thiamine deficiency is not common. However, people with Crohn's disease or anorexia, those undergoing kidney dialysis and people with alcoholism are at risk of having low thiamine levels.

A severe deficiency, which is rare in the United States, makes digesting carbohydrates difficult and causes a buildup of pyruvic acid in your blood. That situation can lead to problems with the nervous system, like confusion, loss of feeling in hands and feet and even paralysis of the lower legs. It can also cause breathing difficulties and heart damage. 
Michael T. Murray, ND
Naturopathic Medicine
A deficiency of thiamine (vitamin B1) usually results in fatigue, depression, pins and needles sensations or numbness in the legs, and constipation. Severe thiamine deficiency results in a deficiency syndrome known as beriberi. Symptoms include mental confusion, muscle wasting (dry beriberi), fluid retention (wet beriberi), high blood pressure, difficulty walking, and heart disturbances.

Although severe thiamine deficiency is relatively uncommon, except in alcoholics, many Americans do not consume the RDA of 1.5 milligrams, and subclinical thiamine deficiency is very common. In addition, diuretics, such as furosemide (Lasix), are known to induce thiamine deficiency, and digoxin (Lanoxin) interferes with thiamine in the heart muscle. Individuals taking these drugs require thiamine supplementation (200 to 240 milligrams daily).
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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.