Function

Thiamin (vitamin B1) helps the body's cells convert carbohydrates into energy. It is also essential for the functioning of the heart, muscles, and nervous system.

The main role of carbohydrates is to provide energy for the body, especially the brain and nervous system.

Food Sources

Thiamin is found in:

• Dried milk
• Egg
• Enriched bread and flour
• Lean meats
• Legumes
• Nuts and seeds
• Organ meats
• Peas
• Whole grains

Dairy products, fruits, and vegetables are not very high in thiamin, but when eaten in large amounts, they become a significant source.

Side Effects

A lack or deficiency of thiamin can cause weakness, fatigue, psychosis, and nerve damage.

Thiamin deficiency in the United States is most often seen in people who abuse alcohol (alcoholism). A lot of alcohol makes it hard for the body to absorb thiamin from foods. Unless those with alcoholism receive higher-than-normal amounts of thiamin to make up for the difference, the body will not get enough of the substance. This can lead to a disease called beriberi.

In severe thiamin deficiency, brain damage can occur. One type is called Korsakoff syndrome. The other is Wernicke's disease. Either or both of these conditions can occur in the same person.

There is no known poisoning linked to thiamin.

Recommendations

The Recommended Dietary Allowance (RDA) for vitamins reflect how much of each vitamin most people should get each day. The RDA for vitamins may be used as goals for each person.

How much of each vitamin you need depends on your age and gender. Other factors, such as pregnancy and illnesses, are also important. Adults and pregnant or breast-feeding women need higher levels of thiamin than young children.

Dietary Reference Intakes for Thiamin:

Infants

• 0 - 6 months: 0.2* milligrams per day (mg/day)
• 7 - 12 months: 0.3* mg/day

*Adequate Intake (AI)

Children

• 1 - 3 years: 0.5 mg/day
• 4 - 8 years: 0.6 mg/day
• 9 - 13 years: 0.9 mg/day

Adolescents and Adults

• Males age 14 and older: 1.2 mg/day
• Females age 14 to 18 years: 1.0 mg/day
• Females age 19 and older: 1.1 mg/day

The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods.

Alternative Names

Vitamin B1; Thiamine

References

Escott-Stump S, ed. Nutrition and Diagnosis-Related Care. 6th ed. Philadelphia, Pa: Lippincott Williams & Wilkins; 2008.

Sarubin Fragaakis A, Thomson C. The Health Professional's Guide to Popular Dietary Supplements. 3rd ed. Chicago, Il: American Dietetic Association;2007.

Institute of Medicine. Food and Nutrition Board. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, PantothenicAcid, Biotin, and Choline. National Academy Press, Washington, DC, 1998.

Rakel D, ed. Integrative Medicine. 2nd ed. Philadelphia, Pa: Saunders Elsevier; 2007.

Mason JB. Vitamins, trace minerals, and other micronutrients. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 237.

Update Date: 2/15/2012

Reviewed by: Alison Evert, MS, RD, CDE, Nutritionist, University of Washington Medical Center Diabetes Care Center, Seattle, Washington. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.