Parents beware - allowing your young child to consume soft drinks may increase their risk of developing behavioural problems, including aggression.

The consumption of soft drinks has previously been linked to aggression and depression in teenagers, however until now, their effect on younger children has not been assessed.

US scientists decided to investigate this issue. They looked at around 3,000 five-year-old children who were taking part in an ongoing study of mothers and their children.

The amount of soft drinks the children consumed was reported by their mothers, who were also responsible for completing a behaviour checklist based on the previous two months.

The study found that 43% of the children consumed at least one serving of soft drinks per day, while 4% consumed four or more servings per day.

The study also found that aggression, attention problems and withdrawal were all linked to the consumption of the drinks. These results stood even after other factors were taken into account, such as socioeconomic factors, whether a mother had depression and violence in the home.

"We found that the child's aggressive behavior score increased with every increase in soft drinks servings per day," the scientists said.

Behavior problems were particularly bad among the children who consumed four or more servings per day. They were more than twice as likely to get into fights, physically attack other people and destroy things belonging to others.

They also tended to withdraw more and display more attention problems than children who did not consume soft drinks.

While the reason for these findings is unclear, the scientists believe that limiting or stopping a child from consuming these drinks could reduce behavioural problems.

Details of these findings are published in The Journal of Pediatrics.