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VITAMINS: Vitamin B-1 (Thiamin)

Overview of Vitamins | Vitamin A (and Beta Carotene) | Biotin (Vitamin H) | Vitamin B-1 (Thiamin) | Vitamin B-2 (Riboflavin) | Vitamin B-3 (Niacin or Nicotinic Acid) | Vitamin B-5 (Pantothenic Acid) | Vitamin B-6 (Pyridoxine) | Vitamin B-12 (Cobalamin) | Vitamin C (Ascorbic Acid) | Vitamin D | Vitamin E | Folate (Folic Acid) | Inositol | Choline


Vitamin B-1 (Thiamin)

Functions of Thiamin

  • Plays a key role in the body's metabolic cycle for generating energy.
  • Aids in the digestion of carbohydrates.
  • Is essential for the normal functioning of the nervous system, muscles & heart.
  • Stabilizes the appetite.
  • Promotes growth & good muscle tone.

Deficiency of Thiamin

  • Loss of appetite.
  • Weakness & feeling tired.
  • Paralysis & nervous irritability.
  • Insomnia; loss of weight; vague aches & pains.
  • Mental depression & constipation.
  • Heart & gastrointestinal problems.

People with an increased risk of Vitamin B1 deficiency

  • Heavy drinkers.
  • Smokers.
  • Pregnant women.
  • Women on the pill.

Recommended dietary allowance for Thiamin

See Recommended dietary allowances for vitamins.

Food sources of Thiamin

Thiamin is found in large amounts in lean pork, legumes and yeast. Whole grain products, breads and cereals are the major dietary contributors.

Clinical uses of Thiamin

  • Therapeutic in case of thiamin deficiency: therapy is urgent, should bypass the intestinal tract, and consists of parenteral administration of thiamin (intramuscular or intravenous) as 50-100 mg/day for 7-14 days, followed by oral thiamin therapy. In clinical disorders related to thiamin deficiency.
  • Prophylactic in persons susceptible to thiamin deficiency: More moderate doses may be prudent for cancer patients in need of nourishment.

Toxicity of Thiamin

  • Oral thiamin: no toxicity.
  • Intravenous thiamin: only a few reports of toxic reactions, resulting mainly in an anaphylactic reaction.