Thiamin
(Vitamin B1)

Description

Thiamin is also known as vitamin B1 and was first isolated from rice polishings in 1926.

STABILITY

Thiamin is one of the vitamins most easily attacked by environmental conditions. It is water-soluble and is lost by leaching into cooking water or dripping from thawed frozen foods. It is also destroyed rapidly by alkalis (e.g. bicarbonate of soda) and ultra violet light. Additionally, the preservative Sulphur dioxide destroys thiamin.

Functions

Thiamin functions in the body as part of the coenzyme thiamin pyrophosphate. This coenzyme is vital for the release of energy from carbohydrates, fats and alcohol.

Deficiency

A severe deficiency of thiamin is now rarely seen in the West, but extremely low intakes lead to a condition known as beri-beri, which is fatal if not quickly treated with thiamin. Symptoms of beri-beri are muscle weakness, nausea, a loss of appetite and Water Retention leading to heart and lung damage.

Minor thiamin deficiencies are known to cause mental conditions such as Depression, irritability, lack of concentration and memory loss. Loss of weight and gastrointestinal upsets are also noted.

Requirements

Upper safe level for daily supplementation = 100mg

Recommended Daily Allowance = 1.4mg

Supplemental Uses

Thiamin may be taken in supplement form to guard against any possibility of a deficiency.

Factors that increase the need for thiamin are:

High carbohydrate intake
High alcohol intake (1)
Physical or mental Stress (2)
Insect Repellant:
Some individuals appear to find thiamin effective as an insect repellant. Controlled trials are required to confirm this (1).

Mood Enhancer:
Thiamin supplementation has been shown to improve mood, making people feel more composed, energetic and clear-headed compared to those not taking the supplements (3).

Safety

Long term oral intakes of up to 3000 mg/day have not caused undesirable side effects in adults.

Interactions and Contra-Indications

There are no contra-indications recorded for thiamin.

Food Sources

Food (mg/100g)
Yeast extract 3.1
Fortified breakfast cereal 1.8
Soya beans, dry 1.1
Pork chop 0.57
Rice 0.41
Bread, wholemeal 0.34
Peas, frozen 0.32
Peanuts, roasted 0.23
Bread, white 0.21
Potatoes 0.2
Chicken 0.11
Beef, stewing steak 0.06
Milk 0.05

The main sources of thiamin in the diet are bread and cereal products, potatoes, milk and meat.

References

1. "Handbook of Dietary Supplements", Pamela Mason, Blackwell Science, 1995.
2. Romero IA, et al. Early metabolic changes during m-Dinitrobenzene neurotoxicity and the possible role of oxidative stress. Free Radical Biol Med,18;2:311-319, 1995.
3. Benton D, Griffiths R, Haller J. Thiamine supplementation mood and cognitive functioning. Psychopharmacology, 129:66-71, 1997.