Iced tea increases risk of kidney stone formation and surgery

Loyola University Chicago Stritch School of MedicineJul 21 2010

Mark Mulac was an "avid lover" of iced tea, downing up to six glasses a day of the popular summertime thirst-quencher.

"I was a junkie on a bender. I had to have it every day," said Mulac, a resident of Brookfield, Ill. "Iced tea was very refreshing, cheap to buy and easy to make."

Unfortunately, for health reasons, Mulac has been forced to go cold turkey. All the iced tea he was downing helped to bring on an excruciating bout of kidney stones that eventually led to surgery at Loyola University Hospital in Maywood, Ill.

"The pain was so bad that once it felt like I was delivering a child made out of razor blades," said the 48-year-old Mulac. "I really had no idea that iced tea could lead to that."

Iced tea contains high concentrations of oxalate, one of the key chemicals that lead to the formation of kidney stones, a common disorder of the urinary tract that affects about 10 percent of the population in the United States. Though hot tea also contains oxalate, it isn't as easy to consume a quantity large enough amount to encourage the formation of stones.

"For many people, iced tea is potentially one of the worst things they can drink," said Dr. John Milner, assistant professor, Department of Urology, Loyola University Chicago Stritch School of Medicine, Maywood, Ill. "For people who have a tendency to form kidney stones, it's definitely one of the worst things you can drink."

Kidney stones are a common disorder of the urinary tract that affects about 10 percent of the population in the United States. Men are four times more likely to develop kidney stones than women, and the risk rises dramatically once they reach their 40s. Postmenopausal women with low estrogen levels and women who have had their ovaries removed also have an increased risk of developing stones.

Kidney stones are small crystals that form from the minerals and salt normally found in the urine in the kidneys or ureters, the small tubes that drain urine from the kidney to the bladder. Most of the time kidney stones are so small that they are harmlessly expelled from the body. But on some occasions, the stones grow to the point that they can become lodged in the ureters.

The most common cause of kidney stones is the failure to drink enough fluids. During the summer, people are generally more dehydrated due to sweating. The dehydration combined with increased iced tea consumption raises the risk of kidney stones, especially in people who are prone to develop them.

"People are told that in the summertime they should drink more fluids," said Milner, who treated Mulac's kidney stones. "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."

The popularity of iced tea has grown dramatically with more than 2 billon gallons consumed a year in the U.S., according to the Tea Association of the U.S.A. Nearly 128 Americans drink the beverage daily.

Much of iced tea's appeal is due to the belief that it is healthier than other beverages such as soda and beer.

"I stayed away from carbonated drinks for a long time because I thought it was upsetting my stomach and that it wasn't as good for me, but I guess overdid it with the iced tea," Mulac said.

To quench thirst and to properly hydrate, there is no better alternative than water, Milner said. You might try flavoring it with lemon slices. Lemonade helps to ward off kidney stones.

"Lemons are very high in citrates, which inhibit the growth of kidney stones," Milner said. "Lemonade, not the powdered variety that uses artificial flavoring, actually slows the development of kidney stones for those who are prone to the development of kidney stones."

Milner also said people concerned about developing kidney stones should cut back on eating foods that also contain high concentrations of oxalates such as spinach, chocolate, rhubarb and nuts. They should ease up on salt, eat meat sparingly, drink several glasses of water a day and eat foods that are high in calcium, which reduces the amount of oxalate the body absorbs.