If you've suffered from kidney stones this summer it may be because you had too much iced tea.
The popular summertime beverage has high concentrations of oxalate -- a key chemical in the formation of kidney stones. Though hot tea also has oxalates, it's not as easily consumed in large quantities like its cold counterpart.
Kidney stones, a disorder of the urinary tract, affect about 10 percent of the United States population. Men are four times more likely to develop these painful crystals than women, and the risk increases for those aged 40 and older, as well as for postmenopausal women with low estrogen or those with their ovaries removed.
The crystals form from minerals and salt and can often be passed painlessly through the urine. But sometimes the stones can grow too large and lodge in the ureters, or the small tubes that drain urine from the kidney to the bladder.
A common cause of kidney stones is dehydration and combining this lack of fluids with an over-consumption of iced tea can raise the risk of developing the disorder.
"For many people, iced tea is potentially one of the worst things they can drink," Dr. John Milner, assistant professor in the Department of Urology at Loyola University Chicago Stritch School of Medicine, said in a statement. "For people who have a tendency to form kidney stones, it's definitely one of the worst things you can drink."
Americans consume more than 2 billion gallons of iced tea each year, according to the Tea Association of the U.S.A. And its appeal might come from the belief that it's healthier than soda and beer.
But the best way to hydrate, Milner said, is to drink water or real lemonade (not the artificially-flavored kind). Lemons have large amounts of citrates, which help deflect the growth of kidney stones.
"People are told that in the summertime they should drink more fluids," Milner said. "A lot of people choose to drink more iced tea, thinking it's a tastier alternative. However, in terms of kidney stones, they're actually doing themselves a disservice."
Milner suggests that those prone to kidney stones stay away from other foods high in oxalates like spinach, chocolate, rhubarb and nuts, and instead consume foods and drinks high in calcium which can reduce the amount of oxalates the body absorbs.
