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Vitamins and Calcium Supplements (cont.)

Medical Editor:

Thiamin (vitamin B1)

What is thiamin, and what does it do?

Thiamin is another one of the water-soluble B vitamins. It was previously known as vitamin B1 or aneurine and can also be spelled thiamine. Thiamin is involved in numerous functions:

  • metabolism of carbohydrates,
  • nervous system functioning,
  • producing hydrochloric acid,
  • muscle functioning,
  • flow of electrolytes in and out cells, and
  • multiple enzyme processes.

How much thiamin do I need to consume?

The Recommended Dietary Allowance for thiamin is:

Age Males Females Pregnancy Lactation
1 to 3 yrs 0.5 mg 0.5 mg
4 to 8 yrs 0.6 mg 0.6 mg
9 to 13 yrs 0.9 mg 0.9 mg
14 to 18 yrs 1.2 mg 1.0 mg
19+ years 1.2 mg 1.1 mg
All Ages 1.4 mg 1.4 mg

There is insufficient information to establish an RDA for thiamin for infants. In this case, an Adequate Intake (AI) has been established:

Age Males and Females
0 to 6 months 0.2 mg
7 to 12 months 0.3 mg

What are sources of thiamin?

Food Amount Thiamin Content
Beans, black, cooked 1 cup 0.42 mg
Bread, white, enriched 1 slice 0.11 mg
Bread, whole wheat 1 slice 0.10 mg
Cantaloupe ½ fresh 0.11 mg
Carrot juice, canned 1 cup 0.217 mg
Cereal, fortified 1 cup 0.5 mg-4.0 mg
Cereal, wheat germ 1 cup 4.47 mg
Egg, whole 1 large 0.03 mg
Lentils, cooked ½ cup 0.17 mg
Long grain brown rice, cooked 1 cup 0.19 mg
Long grain white rice, enriched, cooked 1 cup 1.06 mg
Long grain, white rice, not enriched, cooked 1 cup 0.25 mg
Milk 1 cup 0.10 mg
Nuts, Brazil 1 oz (6-8) 0.18 mg
Nuts, pecans 1 oz (20 halves) 0.19 mg
Orange 1 medium 0.10 mg
Peas, cooked ½ cup 0.21 mg
Pecans 1 oz 0.19 mg
Pork, cooked 3 oz 0.72 mg
Spinach, cooked ½ cup 0.09 mg

Do I need to take a thiamin supplement?

Your body can run out of the small amount of thiamin that it can store in only 14 days, so you need to consume it on a consistent basis. Thiamin deficiency has been seen in people taking strong diuretics and in alcoholics. Thiamin can also be lost during cooking. One study determined the amount lost based on the source of thiamin and cooking method and found

  • 20%-35% lost in water that is discarded after cooking vegetables,
  • 43% loss in pork loin that is roasted (three times as much as lost during braising),
  • 15% loss in bread that is baked, and
  • no loss in double broiler cooking of whole grain cereals.

Thiamin can be in the form of thiamin hydrochloride and thiamin mononitrate in multivitamins, B complex vitamins, or individual supplements.

What happens if I don't have enough thiamin?

Thiamin was one of the first vitamins to be discovered. A deficiency in thiamin can cause weakness, fatigue, nerve damage, and psychosis. Beriberi is the disease that is caused by a severe thiamin deficiency. Beriberi is categorized as wet, dry, or cerebral, depending on the systems that it affects. Wernicke-Korsakoff syndrome can also be caused by a severe thiamin deficiency. Brain damage can occur as a result of this.

Is there such a thing as too much thiamin?

Thiamin is safe enough that no tolerable upper limit (UL) has been established for it. There are no health benefits from extremely high supplementation, so there is no need to take excessive quantities.

Next: Niacin


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