By Stephenie Overman
Sweet iced tea is a summer staple. So are warnings about tea and kidney stones.
Drinking “an excess amount” of tea can cause stones, Dr. Pooja Singh, a clinical assistant professor in nephrology at Jefferson University Hospital in Philadelphia, told the PhillyVoice.
People who have a genetic predisposition or a family history of kidney stones are more likely to develop stones, Singh said in the interview. “And more so if they drink too much black tea, and that’s because of the fact kidney stones are made up most commonly of calcium oxalate and the oxalate is quite high in black tea.”
It’s recommended that an individual limit intake to less than 100 milligrams of oxalate per day. “With black tea if you drink about three ounces, that could have about 50 milligrams of oxalate. If you’re going to drink two or three glasses, I think it’s OK. Even four or five, it might be fine… If you’re going to drink 10 glasses, it’s too much I’d say.”
But the bigger worry in summery sweet tea is the sweetener. In an analysis of three studies, researchers found that participants who consumed sugary beverages such as soda at least once a day had a 23 percent higher risk of developing kidney stones, compared to participants who consumed them less than once a day. Coffee, orange juice and tea were associated with a lower risk of kidney stones.
The 2013 analysis, which involved 194,095 participants, was published in the Clinical Journal of the American Society of Nephrology.
This study “confirms that some beverages are associated with a lower risk of kidney stone formation, whereas others are associated with a higher risk,” Pietro Manuel Ferraro, an author of the study, told Bel Marra Health.
“Although higher total fluid intake reduces the risk of stone formation, this information about individual beverages may be useful for general practitioners seeking to implement strategies to reduce stone formation in their patients,” Ferraro said.