Grown ups are again agonising over what our children eat and drink.

SO Ribena's Tooth Kind is not as kind to teeth as its makers would have us believe - at least according to the Advertising Standards Authority.

The ASA received several complaints about a poster advert which depicted bottles of the blackcurrant drink as bristles on a toothbrush.

It upheld the complaints, saying the poster "wrongly implied Ribena Tooth Kind actively benefited oral health".

Makers SmithKline Beecham has vigorously defended the drink saying it has no added sugar; that it was lower in fruit acids than competitors; that it had added calcium and is the only drink to be accredited by the British Dental Association.

It has already won High Court permission to seek a judicial review of the ASA's decision.

However, the verdict throws into further confusion what is good and bad for children.

Dentist Stuart Robson, of the Robson, Nicholson and Alpin practice in Blossom Street, York, says he often comes across tooth decay in children caused partly by soft drinks.

"One of the things that drives us to distraction is you walk down Coney Street, or any other street, and you see lots of children clutching cans of fizzy drink," he said.

"And you know as soon as they throw it away they'll buy another one.

"It's the concentration that's so damaging - so many kids have one can after another."

Fizzy drinks are particularly bad for your teeth, explained Mr Robson, a former president of the British Dental Association.

"They can be just as bad as sugary drinks. If you get fizzy, sugary drinks that's a double whammy."

The fizz is carbon dioxide, which reacts with the water in the drinks to produce carbonic acids.

"It's the acid which attacks enamel in the teeth, particularly in children's teeth which haven't fully matured and are therefore a bit softer. Sugar aggravates the attacking process."

Sparkling water is not so harmful because it contains no sugar and the fizz is less concentrated, Mr Robson added. The best drinks for children are milk, which contains calcium, and still water.

But Mr Robson said that if children found that boring, squashes were a reasonable alternative - particularly those with no sugar added - as well as natural fruit juices.

Meanwhile, the Government has just launched the first set of minimum school meal standards for 20 years.

Government guidelines due to start in 2002 have set down national nutritional standards for school dinners aimed at encouraging a healthy diet.

Ministers want to see fresh fruit at least twice a week and fruit in a dessert at least once a day.

Milk and dairy produce must be a prominent part of the school menu, along with rice and pasta.

School dinners can affect more than just the health of the child. Teachers have claimed that bad behaviour and an inability to concentrate are direct consequences of a poor diet.

PICTURE: Some of the drinks on the market which are enjoyed by children