If you drink iced tea, listen up. Even though it’s one of the healthiest beverages you can drink, there’s a hidden danger. On the good side, tea lessens stress, helps prevent heart disease and stroke, and even helps preserve memory. However, for some people - it can raise the risk of painful kidney stones. That’s the word from Dr. Mark Mulac. He’s a urologist with the Loyola University Health system in Maywood, Illinois, and he loves iced tea so much he was drinking up to six glasses a day in the summer. He was forced to give it up when it brought on a bout of kidney stones that eventually led to surgery. Mulac says the pain was excruciating.

So why does iced tea lead to kidney stones? It contains high concentrates of oxalate, and that’s one of the key ingredients in kidney stones, which are crystals that form in the kidneys. About one in 10 people get the them, with men being four times as likely as women. Also, a man’s risk rises dramatically once he’s in his 40s. Dr. John Milner, an instructor in the department of urology at Loyola University Chicago Stitch School of Medicine, says the most common cause of kidney stones is actually dehydration. In the summer, when people are sweating more, they also drink more iced tea – thinking it’ll help keep them hydrated. They don’t realize they’re making things worse.  

So what SHOULD you drink? Milner says there’s no better choice than plain old water – period. You can flavor it with lemon if you want to add some zing, and water actually helps ward off kidney stones. Also, if you’re prone to developing them, you should cut back on chocolate, nuts, and spinach - all of which have high concentrations of oxalates.