Vitamin B1 

Vitamin B1, also known as thiamin, is essential for the transmission of certain types of nerve signals between the brain and the spinal cord. It is also crucial for the workings of particular types of enzymes that make energy available in the body. Body stores are relatively small and so regular intakes are vital.

Absorption helpers Vitamin C and citric acid, found in oranges and other citrus fruits, may help to prevent thiamin destruction, while B vitamins tend to work together to enhance one another's absorption.

Absorption inhibitors Long-term intakes of antacids reduce B1 levels in the body, as do high intakes of alcohol. Caffeic acids in coffee, tannic acids in tea, and sulphur dioxide used in the drying of fruit adversely affects vitamin B1 absorption and destroy thiamin. Eating sushi regularly may reduce absorption as raw fish contains thiamin-breaking enzymes.

Taking thiamin supplements

The adult RDA for thiamin (1.4mg a day) is equivalent to one bowl of fortified breakfast cereal. Large single doses of thiamin are poorly absorbed by the body, so it is best to have 100 per cent of the RDA on a regular basis. No long- or short-term effects have been established in adults taking up to 100mg supplements a day. Optimum nutritionists recommend 3.5-9.2mg per day to maintain health, and 25-100mg a day for therapeutic use.

Combining supplements Taking vitamin B1 supplements together with vitamins B2 and B6 appears to help B1 to work more effectively in the body.

Precautions Intakes greater than 50mg per kilogram of body-weight, or 3g per day have been shown to be toxic. Such levels have led to symptoms such as a rapid pulse, inability to sleep, general weakness, headaches, and irritability. Too much thiamin may lead to the loss of other B vitamins from the body.

Why take this supplement?

Full-blown thiamin deficiency, known as beriberi, is unusual in western countries. Alcoholism is a main cause of thiamin deficiency but a stressful life, physically active people, and those over 55 may benefit from taking supplements. B1 deficiency may trigger these symptoms:

Therapeutic uses

• Improved memory Thiamin is necessary for the glucose in the blood to produce a substance called acetylcholine, which transmits messages between nerves and is crucial for the memory and for concentration levels. It has been suggested that eating a breakfast that includes both carbohydrate, which increases blood glucose levels, and thiamin, which facilitates acetylcholine production, may lead to improved memory functioning in the morning ahead.

• Decreased sugar cravings A mild deficiency of thiamin may lead to sugar cravings, which could be improved through a modest intake of the supplement.

• Alzheimer's disease New studies have shown that thiamin supplements might be helpful for preventing and slowing Alzheimer's disease - essentially a disease of ageing - which is characterized by forgetfulness.

• Multiple sclerosis Doctors may prescribe thiamin supplements to treat a range of disorders of the nervous system, such as the disease multiple sclerosis, Bell's palsy, and neuritis.

Chemical names

• Thiamin

Preparations
 

• Capsules

• Tablets

RDA for adults

1.4mg

Top sources of Vitamin B1 mg/100g of food

• Yeast extract4.25mg/100g

• Peas0.89mg/100g

• Oranges0.70mg/100g

• Fortified cornflakes0.65mg/100g

• Boiled potatoes0.59mg/100g

• Wholewheat pasta0.43mg/100g

• Wholemeal bread0.37mg/100g

• Egg yolk0.30mg/100g

• White bread0.21mg/100g