http://www.nytimes.com/2008/01/22/health/nutrition/22real.html?_r=1&em&ex=1201323600&en=0b011f7ae8332dcb&ei=5087

The Claim: Too Much Cola Can Cause Kidney Problems

It is well known that too much soda can increase the risk of diabetes and obesity. But when it comes to kidney problems, is there a difference between colas and other kinds of soda?

Colas contain high levels of phosphoric acid, which has been linked to kidney stones and other renal problems.

Much of this conclusion stems from anecdotal and circumstantial evidence. So last year, a team of scientists at the National Institutes of Health took a closer look.

In a study published in the journal Epidemiology, the team compared the dietary habits of 465 people with chronic kidney disease and 467 healthy people. After controlling for various factors, the team found that drinking two or more colas a day — whether artificially sweetened or regular — was linked to a twofold risk of chronic kidney disease.

But drinking two or more noncola carbonated drinks a day, they found, did not increase the risk.

The authors of the study say more research is needed, but their findings support the long-held notion that something about cola — the phosphoric acid, for example, or the ability of cola to pull calcium from bones — seems to increase the risk of kidney stones, renal failure and other conditions affecting the kidneys.

THE BOTTOM LINE

There is good evidence that cola beverages can increase the risk of kidney problems, more so than noncola sodas.