Vitamin B1

Vitamin B1 - also known as thiamin or thiamine - is a water-soluble vitamin that plays an important role in metabolism and the way nerves and muscle cells conduct messages.

Why you need vitamin B1

Vitamin B1 is essential for the production of energy from blood sugar (glucose), for healthy nerves and muscle cells - including those in the heart - and for the production of red blood cells. It is also needed for the synthesis of some important amino acids.

Research

Vitamin B1 has a beneficial effect on mood, helping you feel more calm, agreeable, clear-headed, elated and energetic. People with low levels of thiamine are less likely to feel composed or self-confident and more likely to suffer from depression than those with higher levels. Many people over the age of 55 have low intakes of thiamin - supplements may help to increase feelings of general well-being, improve fatigue and boost appetite.

How much you need:

The EC RDA for thiamin is 1.4mg. It is non-toxic as excess is readily lost in the urine.

In general, the more carbohydrate you eat, the more thiamin you need. As vitamin B1 is water soluble, it is easily lost from the body through the kidneys and most people only have stores sufficient to last one month. A regular dietary supply is therefore essential, otherwise deficiency quickly occurs.

People drinking large amounts of coffee or tea - which destroy the vitamin - may become thiamin deficient. Other common causes of thiamin deficiency include stress - which quickly uses up available thiamin stores - and drinking too much alcohol, which interferes with thiamin metabolism.

Lack of vitamin B1 leads to a form of anaemia in which red blood cells become larger than normal. In underdeveloped countries, thiamin deficiency is common especially where the main dietary staple is polished rather than brown rice. This causes a disease known as beri-beri which means 'extreme weakness'. Dry beri-beri produces heaviness, weakness, numbness and pins and needles in the legs, while wet beri-beri causes severe fluid retention. In those with a high alcohol intake, lack of thiamin is associated with Wernicke-Korsakoff syndrome which, if left untreated, leads to irreversible dementia.

Symptoms that may be due to vitamin B1 deficiency include:

tiredness
headache
loss of appetite
nausea
constipation
depression
irritability
loss of concentration
poor memory
muscle weakness and stiffness
nerve tingling, burning and numbness
progressive paralysis

Foods containing vitamin B1 include

brewer's yeast and yeast extracts
wholegrain bread and cereals
brown rice, wheat germ, wheat bran
oatmeal and oatflakes
soya flour
pasta
meat - especially pork and duck
seafood
pulses
nuts

Thiamin is easily lost by food processing e.g. chopping, mincing, liquidizing, canning and preserving. Boiling reduces the thiamin content of foods by half as it is so water soluble. It is also destroyed by high temperatures and adding baking powder. Toasting bread can lose almost a third of its thiamin content.

Vitamin B1

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