Vitamins, Minerals and Dietary Supplements
Vitamin B1 (thiamin)
What is vitamin B1?
Also known as thiamin, vitamin B1 is a water-soluble vitamin. Since it
is not stored in body fat, after the body uses what it needs, any excess
vitamin B1 is excreted in the urine.
Why do we need it?
Like most of the B vitamins, thiamin plays a variety of roles in the
human body. Its most important function is to help the body's cells convert
carbohydrates into ATP the fuel the body runs on. It is also involved
in metabolic activities relating to the heart, brain and muscles, and
it helps ensure proper nerve cell function.
How much vitamin B1 should I take?
According to the National Academy of Science, the recommended daily allowance
(RDA) for thiamin is as follows:
- Adult men: 1.5 milligrams/day
- Adult women: 1.1 milligrams/day
- Children aged 7-10: 1 milligram/day
- Infants: 0.4 milligrams/day
- Pregnant/lactating women: 1.6 milligrams/day
What are some good sources of vitamin B1?
Thiamin is found in almost all foods, but the best sources are pork and
other lean meats. Other good sources include enriched and fortified cereals,
oatmeal, corn, nuts, beans, cauliflower and sunflower seeds.
What can happen if I don't get enough vitamin
Vitamin B1 deficiency can result in edema and abnormal heart rhythm.
Severe B1 deficiency (also known as beriberi) is rare in the U.S. but
can occur in severely malnourished people, alcoholics, or people on long-term
dialysis. Symptoms may include paralysis, loss of balance, loss of feeling
in the legs and feet, visual problems and congestive heart failure.
What can happen if I take too much?
To date, no toxic effects have been reported for vitamin B1. Because
it is water-soluble and is not stored in the body, the chances of enough
B1 building up to toxic levels are highly unlikely. Most people taking
multivitamins with high levels of B1 or eating foods rich in amounts of
B1 need not worry about toxicity.
- B vitamins may cut heart disease risk. Harvard
Health News April 1998.
- B vitamins and the heart: what men can learn from
women. Harvard Men's Health Watch June 1998.
- Cheraskin E, Ringsdorf WM, Medford FH, Hicks BS. The
"ideal" daily vitamin B1 intake. J Oral Med 1978; 33:77-79.
- Recommended Dietary Allowances, 10th ed. Washington,
D.C.: National Academy Press, 1989.
- Insel PM. Thiamin: essential for health. Health
Line November 1995.