Large quantity intake of fruit juice encouraged as part of children's `five a day` is probably damaging their teeth, aver dentists.
The dentists are concerned that health-conscious parents who regularly give their children juices and smoothies bursting with fruit could be doing long-term damage.
Kathy Harley, dean of the dental faculty at the Royal College of Surgeons, warned that half of five-year-olds had signs of wear to their tooth enamel.
She has called on schools to offer milk or water to pupils during breaks instead of fruit juice, which has a high acid content.
Dental erosion, which is irreversible, is caused by acid attacking the surface of teeth - and citrus fruit juices in particular are very acidic.
While fruit juices contain a range of vitamins that are good for your health, they are also often high in natural sugars, which cause tooth decay.
Harley suggested that parents should give their children fruit juice as a treat once a week, for example on Saturdays. The NHS recommends only one 150ml glass of fruit juice per day, which counts as one of the recommended five daily portions of fruit and vegetables.
It suggests that people drink the juice with a meal as this can help to reduce damage to the teeth.
Drinking more than one glass of juice a day does not count as more than one portion of fruit, as it does not contain the fibre found in the whole fruit.
Juicing or blending fruit releases the sugars inside and is worse for the teeth if drunk frequently.
Some researchers also say drinking juice slowly can cause more damage to teeth.
Dentists had previously warned that, while tooth decay is less common as more children and adults brush their teeth regularly than in the past, dental erosion is a growing problem due to acidic drinks.
The Department of Health said it had no plans to remove fruit juice from the five-a-day.
"It contains nutrients, including vitamins which are important as part of a healthy, balanced diet," the Daily Mail quoted a spokesman as saying.