Energy drinks, many of which contain too much caffeine, may be harmful to children, according to a new study published on Monday.

The finding was based on a review of the literature on energy drinks, researchers at the University of Miami said in the study appearing in the journal Pediatrics.

Many of the energy drinks reviewed contain three times the caffeine of a cola and some of which have five times more, said the study.

The study showed that caffeine in the drinks can exacerbate cardiac conditions, especially in children with eating disorders, and interfere with calcium absorption and bone mineralization in young adolescents.

Energy drinks produce extra calories which can contribute to diabetes, high body mass index and dental problems, according to the study.

Also, energy drinks contain additional ingredients which may boost caffeine levels, said the study.

The study also found that many children and young adults in the United States have tried energy drinks, and some consume them heavily.

A survey of college students reported that 51 percent regularly consumed one or more of the drinks per month, and a majority of those students drank them several times a week.

Insufficient sleep and a desire for more energy were cited as reasons for such consumption, said the study.

The drinks are unregulated in the United States, and the number of overdoses of caffeine from drinking them remains unknown, the study said.

But in Germany, Ireland and New Zealand, officials have reported cases of liver damage, kidney failure, seizures, confusion and arrhythmias associated with energy drink use, according to the study.