How much caffeine is there in a cup of coffee

A.� The average cup of instant coffee contains around 75 mg of caffeine, while an average cup of brewed coffee contains 100mg.

An average cup of tea contains 50mg, regular cola contains 40mg,a regular energy drink can contain up to 80mg, and a small sized bar of chocolate will contain 40mg of caffeine.

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Q.� How does caffeine work

A.� Caffeine occurs naturally in the leaves, seeds and fruits of more than 60 species of plant, including coffee beans, tea leaves, the cola nut and cocoa beans.Iit works on the human body by attaching itself to receptors in the brain which are designed to take another chemical called adenosine. Adenosine is a sedative which slows down brain cell activity, but caffeine overrides this and acts as a mild stimulant.

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Q.� How much coffee is too much coffee

A.� Experts agree that for most people, in moderation coffee can be an enjoyable and valuable part of a healthy balanced diet. But there are certain groups of people who could benefit from avoiding or cutting down on caffeine. The Food Standards Agency recommends that pregnant women limit their intake of caffeine to less than four cups a day.

Experts agree that up to two cups of coffee a day can be enjoyed.

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A review of diet and cancer published by the World Cancer Research Fund in 1997 concluded that there was no evidence linking cofee with increased cancer at any site in the body. In fact, there is evidence to suggest it may help protect against colon cancer.

An analysis of 17 studies from 1960 to 1990 on coffee consumption and colorectal cancer, published in the American Journal of Epidemiology in 1998, found the risk to be 24 per cent lower in people who drink four cups a day compared with those who rarely or never drink coffee.

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Q.� Does it really keep you awake

A>� It's a proven fact that cafeeine can improve concentration and attention. One in five road accidents in the UK is caused by drivers falling asleep at the wheel. The AA says regular coffee breaks can help drivers stay awake and alert.

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By Katharine MacColl