What Is It?
Vitamin B1, also known as thiamin, is a water soluble vitamin. Although other biochemists had been working on extracts of rice polishings (husks) for some years it was not until 1926 that the first pure thiamin was isolated and named "aneurine". It was later renamed thiamin when the chemical structure was totally identified in 1934 by Dr Robert Williams. In common with most of the other vitamins in the B complex group any excess vitamin B is excreted from the body. The body cannot store much of it so it must be replaced daily. B1 is considered the most unstable of the B complex group since it can be fairly easily destroyed especially in the cooking process.
What Vitamin B1 Does For You
- Vitamin B1 promotes general growth.
- It plays an essential role in the metabolism of carbohydrates (i.e. converting them to energy).
- The digestive system needs it in order to function correctly.
- It has been claimed that a feeling of mental well being is aided by vitamin B1. More factually, mental instability can occur if a person is B1 deficient. Additional B1 can help cure this condition. However, if there is no B1 deficiency, extra B1 will not enhance mental well being.
Food Sources for Vitamin B1
Cereals - wholemeal/white bread (4 slices), fortified breakfast cereals (30g serving), wheat germ (10g serving)
Yeast products e.g. Marmite/Vegemite (3g serving)
Meat - liver (100g serving), pork (chop), bacon (rashers), lean beef, chicken, lamb, veal (125g serving)
Nuts (50g serving)
Pulses, cooked e.g. soya beans, lentils (100g serving)
Dairy product - full cream/skim milk, yoghurt (250ml serving)
Potatoes, sweet corn (125g serving)
Avocado pear (150g)
Fresh fruit - oranges, pineapple, apples, pears, berry and stone fruit (100g serving)
Vegetables - Brussels sprouts, cabbage, carrots,
peas, pumpkin, squash (60-100g serving)
Fish (100g serving)
Wheat bran (10g serving)
Low or Nil
Fats and oils (trace)
What Destroys B1
B1 is a rather fragile vitamin since it is susceptible to heat and the oxygen in the air.
Being water soluble, cooking B1 rich foods in water, or at a high temperature, is a risky process since the vitamin is extracted from the food and dissolved in the cooking water. The vitamin is also lost in drips from thawing frozen food.
A substantial loss of B1 occurs in the process of milling wheat used in the manufacture of most breakfast cereals. These days, however, many cereals are B1 enriched by the manufacturer after the milling process.
Some preservatives used in making processed meat kill the vitamin.
Alkaline conditions, caused by adding bicarb soda to cooking water or baking powder to cakes, destroys B1.
It is important to note that thiamin has certain natural enemies. Alcohol is the Number 1 enemy.
Other food containing enzymes that break down thiamin include raw fish, oysters, tea and coffee.
Deficiency Problems and Symptoms
Severe deficiency causes beriberi. This serious disease is quite rare in Western society but is only too common in poor third world countries where a diet of "polished" rice (i.e. where the vitamin-rich hulls have been removed from the rice) results in a low intake of vitamin B1.
That beriberi was caused through diet was first recognized in the late nineteenth century by a Japanese doctor, but it was not until almost twenty years later that the vitamin pioneer Casimir Funk identified the substance later to become known as vitamin B1.
A mild deficiency can cause fatigue and irritability, progressing to pains in the legs and feet.
The most serious vitamin deficiency disease in Australia today is Wernicke's encephalopathy - a severe mental disorder. The victims of this disease are usually alcoholics although it can occur in people who do not drink at all.
In Australia, and other Western societies, the group most at risk of vitamin B1 deficiency are heavy drinkers or alcoholics. Alcohol abuse generally results in overall poor eating habits, but alcohol itself also inhibits the digestive system's ability to fully utilize many important nutrients, particularly vitamin B1.
It has been suggested, with some degree of seriousness, that alcohol should be "enriched" with B1.
In much the same way as vitamin D is added to milk in North America and other countries. However in dealing with alcoholism (one of Australia's most serious health problems) this suggestion would seem to be putting the cart before the horse.
Recommended Daily Intake
The Australian recommended intake is 1.1 milligram, slightly less for women except if they are pregnant or breast feeding when the intake should be slightly higher.
Because vitamin B1 activates the metabolism of high energy foods (carbohydrates) this recommended figure is closely related to each individual's energy intake (kilojoules), together with age and weight factors.
Use of Supplements
(on medical advice)
B1 is essential in the treatment of beriberi.
Large doses of B1 are very effective in the treatment of Wernicke's encephalopathy, particularly in the early stages of the disease.
When vitamin B1 is taken orally toxicity is virtually non existent even at doses as high' as hundreds of milligrams.