With sports days looming and temperatures soaring, it’s the time of year when parents worry about whether their children are getting enough to drink. Long school days with little access to liquid can leave kids dehydrated.

We know that, despite their protestations, we shouldn’t allow children to indulge their love of fizzy cola-style drinks as they are high in sugar, caffeine and artificial additives. So we send them off with cartons of fruit drinks, which not only keep them hydrated but also give them part of their recommended daily intake of vitamins B and C. Packaged in groovy sports- cap bottles or cartoon-covered cartons, and aimed specifically at children, drinks such as Ribena, Robinsons Fruit Shoots and Five Alive are seen as a healthy option.

But the reality can be different. In fact, many have little nutritional value beyond the added vitamins. Often the fruit juice content is shockingly low — as little as 6 per cent — and this is made up from fruit concentrate, which has lost most of its natural flavour and vitamins. Large amounts of sugar or sweeteners are used to give the drink flavour, often more than 10g per 100ml. “This is considered a lot of sugar,” says the Food Standards Agency.

But does this matter? Surely a “juice” drink, regardless of the artificial additives it contains, is better than no drink? Apparently not. Our bodies are made from 50-70 per cent water and our brains 85 per cent, and without sufficient replenishment a child will become tired, lack concentration and be prone to headaches.

Alex Richardson, a senior research fellow at Oxford University and an expert in how nutrition affects children’s behaviour, says: “Sweet drinks are not acceptable substitutes for water: most have undesirable ingredients and some of the ‘healthy’ energy drinks on the market contain caffeine, which acts as a diuretic and can actually cause you to lose water.”

Jennette Higgs, a nutritionist for the Health Education Trust, agrees that water is the best drink. “The trouble is that if children are always being given sweetened drinks it’s harder to encourage them to drink water and enjoy it.” She has other concerns, not least the rise in childhood obesity: “All these drinks add unnecessary sweetness, either sugar or artificial sweeteners, which encourage a sweet tooth.”

The long list of additives in many juice drinks is another worry. Dr Richardson says: “My basic rule is if a drink contains artificial sweeteners and unfamiliar ingredients. it’s better not to choose it.”

Jane Clarke, the Times nutritionist, had to establish some rules when it came to her daughter, Maya, drinking cordial and squashes. “I’ve had to stop my mum offering Maya sweet drinks; it might be only a little fruit squash mixed into water, but she has enough natural sugar in her diet and she likes water, so why add something she doesn’t need? Frequently these squashes and high juices contain so much sugar, preservatives and acids that they’re no better than a can of pop.”

Unfortunately, you can’t assume that it’s OK for your kids to knock back gallons of unsweetened pure fruit juice instead. They’re fine in moderation and if drunk with a meal, as this will reduce the risk of dental erosion from the acid. But Dr Richardson cautions: “Fruit juice can be a way of packing a lot of sugar into the diet, which can make blood sugar levels rise rapidly and then plummet, which can badly affect concentration and behaviour.” Drinking a glass of fruit juice can count as one of a child’s five fruit and veg a day, but there’s no nutritional benefit to drinking more; they won’t count as further portions. She thinks that smoothies are a better option, so long as they contain no extra sugar or additives. They contain whole fruit rather than concentrate, so the vitamins and other nutrients are occurring naturally and cause fewer extreme fluctuations in blood sugar levels. Another bonus is that in the long term children get used to a range of real fruit tastes. Drinking super-sweet fruit-flavoured drinks can make it difficult to get children to eat real fruit, which isn’t as sweet. If children are used to super-sweet processed drinks, real fruit is a shock to the system,” says Dr Richardson.

Higgs recognises that parents need all the help they can get; her own children drink fruit juice by the pint if it’s on offer. The Government’s new standards on drinks in schools will help. From September the sale of juice drinks will be banned and easy access to drinking water will be a requirement.

And there are other signs of positive change on supermarket shelves. Innocent smoothies, which have no additives, are the sixth most popular fruit drink for children; new juice drinks such as Tropicana Go! contain much higher quantities of concentrate juice

(70 per cent) and no sugar or sweeteners. But opinions are divided on the new flavoured water drinks for children, such as Robinson’s H20, which comes in a sports-cap bottle and contains sweeteners and flavouring.

Dr Richardson recognises that it’s unrealistic to expect children to drink plain water all the time, and sees it as a step in the right direction. Higgs is more cautious. “In some respects it is better,” she says. “But why flavour water? How are we ever going to encourage kids to drink plain water? If we’re not careful we’ll end up with a generation of kids who only drink water when they clean their teeth.”

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