Vitamin B1 is a water-soluble vitamin that plays an essential role in many processes in the body. It is required for:

• converting food into energy
• metabolising fats and carbohydrates
• controlling blood sugar
• keeping skin healthy
• maintaining proper functioning of the nervous and digestive systems

Our bodies cannot produce Vitamin B1 and very little can be stored by the body.

We must get B1 from foods and supplements. Depletion can occur quite rapidly so regular, preferably daily, intake is required.

Processing, cooking in water, and defrosting will remove most B1 from foods

Vitamin B1 occurs in low concentrations in many natural foods, but is quite easily lost. Foods that are a good source of B1 include: unrefined grain products, meat, vegetables, dairy, legumes, fruit and eggs.

Your lifestyle may increase the risk of deficiency

Aside from a poor diet, deficiencies can occur due to:

• tea and coffee consumption
• alcohol intake
• smoking

Also, some foods (eg fish, prawns, clams, and mussels) may impair your body's absorption of B1.

Severe B1 deficiency is rare, but even a moderate deficit has health consequences. The symptoms of mild deficiency are similar for all B Group vitamins:

• energy production is reduced which can cause tiredness, irritability, fatigue, and apathy.
• nervous system symptoms appear such as muscle weakness, cramps and numbness.

There are no adverse effects associated with high doses of B1 because the body is efficient at eliminating excess amounts.

‘Safe Upper Levels for Vitamins’ by UK Government Expert Group on Vitamins and Minerals, May 2003