Thiamine - Learn About Vitamins & Minerals
also known as Vitamin B1, is a water-soluble vitamin. It was the
first vitamin to be discovered. Thiamine is one of eight members
of the vitamin B complex. The complex also includes:
- vitamin B2
- vitamin B6
- vitamin B12
- pantothenic acid
Because thiamine is water-soluble, any extra is passed out of the
body in the urine. Thiamine is needed each day to maintain health.
What food source is the nutrient found in?
Thiamine is found in foods such as:
- meats (pork and liver)
- brewer's yeast
- dried beans
- whole or enriched breads, grains, and cereals
Enriched products add back the vitamins that are lost when grains
are processed. Thiamine is lost in cooking due to heat. The thiamine
contents of some foods are:
- beef liver, braised (3 ounces) = 9.2 milligrams (mg)
- sunflower seeds (3.5 ounces) = 1.96 mg
- pinto beans (3.5 ounces) = 0.84 mg
- enriched rice, cooked (1/2 cup) = 0.2 mg
How does the nutrient affect the body?
Thiamine works with the other B vitamins to change protein, carbohydrate,
and fat to energy. It is especially vital for changing carbohydrates
to energy. It is a key factor in the healthy functioning of all
the body's cells, especially the nerves.
Daily needs for thiamine are based on the amount of calories taken
in each day. The recommended daily allowances, called RDAs, for
thiamine are based on 0.5 milligram (mg) for every 1,000 calories
consumed. Based on the recommended calorie intake for men and women
at certain age levels, the RDAs for thiamine are:
- men from 15 to 50 years = 1.5 mg
- men over 50 years = 1.2 mg
- women from 11 to 50 years = 1.1 mg
- women over 50 years = 1.0 mg
- pregnant women = 1.5 mg
- breastfeeding women = 1.6 mg
Thiamine is common in foods. A balanced diet based on the Food
Guide Pyramid should provide enough thiamine daily.
A disease called beriberi, which affects the nerves and heart,
is caused by a lack of thiamine in the diet. This is extremely rare
in the United States, because enriched grain products are so common.
Before grains were enriched, it was much more common.
Mild thiamine deficiencies are more common. Exceptions may be found
with chronic alcoholism, fasting, the elderly, and chronic dieting.
Symptoms usually show up in the nerves, stomach, and heart. Early
warning signs include:
- fatigue and weakness
- loss of appetite and weight loss
- stomach upset and nausea
- confusion and irritability
- poor memory
- sleep disturbances
- chest pain
- abdominal discomfort
If deficiency continues, symptoms can get worse, and some damage
can be permanent. This can include damage to the heart, and changes
to the nervous system.
There is little chance of getting too much thiamine, even when
it is taken at high doses. Because it is water soluble and not stored
in the body, it is not likely to build up to toxic levels. In older
people with low levels of thiamine, taking vitamin B1 pills has
improved their lives by decreasing both blood pressure and weight.
In isolated cases, however, thiamine toxicity has occurred from
injections or concentrated formulas used with hospital patients.
Toxicity symptoms include nervous irritability, headaches, insomnia,
and a rapid pulse.
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