A new study has linked soft drinks to an increased risk of kidney damage. Lead researcher and environmental and nutritional toxicologist, Dr. Peter Dingle, said the study showed popular drinks were particularly bad for children.

Dingle, of Western Australia's Murdoch University, said parents should limit soft drinks for their children.

"A soft drink a week isn't too bad, but aggressive marketing has turned them into replacements for healthy drinks -- water, fruit juice and milk," Dingle said. "Kids are conditioned to drink them all the time."

Dingle studied 30 brands of soft drinks and sports drinks for sugar, pH levels and flavoring.

The study found many had more than 10% sugar, up to seven added flavors and pH levels as low as 2.5 -- highly acidic. Diet soft drinks were the worst for acidity.

The body naturally had a pH level of about 7.2.

"These drinks are putting stress on your kidneys because your kidneys are the first mechanism to balance the pH levels in your body," he said.