"Dear Martina: I am a dad and coach football at my son's school. The boys are active and get very thirsty. Should they avoid sugary drinks? " - Peter Arnold, Patcham

Dear Peter: This is a common dilemma faced by parents and teachers. Ideally, children should be encouraged to drink what the body is designed to drink - pure, still water.

However, surveys show that half of all children don't drink any fluids at school and suffer from impaired concentration, headaches, constipation and infections.

Only 12 per cent of children in the UK choose to drink water, while 21 per cent of seven to ten-year-olds drink nearly ten cans of fizzy drinks per week, most of them bought for them by their parents.

Most "energy drinks" are loaded with sugar, about a teaspoon per fluid ounce.

The huge rise in overall sugar intake is a major contributing factor to obesity, diabetes, lowered immunity and tooth decay.

Some pure fruit juices don't have added sugar and contain nutrients such as vitamin C and A and potassium. But they are still high in fruit sugars and don't contain the fibre of the whole fruit which helps slow down sugar absorption.

Generally, children drink too much fruit juice, replacing other basic nutritional requirements such as protein and essential fatty acids.

Many drinks rely on dubious artificial sweeteners and, according to the Food Commission, nearly 40 per cent of children's foods and drinks contain additives that cause temper tantrums.

In a recent government-sponsored study, food additives were tested on 277 three-year-olds from the Isle of Wight.

The additives used were the artificial food colourings Tartrazine (E102), Sunset Yellow (E110), Carmoisine (E122), Ponceau 4R (E124) and the preservative Sodium Benzoate (E211).

An analysis of the results showed that these chemicals can cause mood changes and disruptive behaviour in every child, not just those who are already hyperactive.

The test doses administered were well below or equal to levels permitted in children's foods and drinks.

Kids are invariably subject to much higher doses because food colourings are added to 78 per cent of children's desserts, 93 per cent of children's sweets, 42 per cent of children's milkshakes, 24 per cent of children's cheeses, 23 per cent of children's cereals and 15 per cent of children's frozen burgers.

Children who play football are common targets for those who are in the business of investing in ill health.

The Food Commission has criticised Manchester United and Blackburn Rovers for linking up with Pepsi, Tottenham Hotspur for working with McDonald's, and Sunderland City for accepting sponsorship from Coca Cola and McDonald's.

Respected football players promote Walkers Crisps and the Football Association itself circulates nutritional advice to schools and football academies that have been written and sponsored by Mars confectionery.

The only Premier League football team to provide sensible health advice to children is West Ham.

Parents who want to see additives removed from children's food and drinks are invited to join the Food Commission's Parents Jury.

Contact The Food Commission on 0207 837 2250 or visit www.parentsjury.org