Friday, August 10, 2012

Iced Tea May Contribute to Painful Kidney Stones

IcedTeaPeople who have a tendency to form kidney stones, or are concerned about developing the painful disorder, should skip that extra glass of iced tea this summer. According to John Milner, MD, a urologist at Loyola University Medical Center, Maywood, IL, iced tea contains high concentrations of oxalate, one of the key chemicals that lead to the formation of kidney stones — a fairly common disorder that affects about 1 in every 10 persons in the United States.

“For people who have a tendency to form the most common type of kidney stones, iced tea is one of the worst things to drink,” Dr. Milner said in a news release on August 2, 2012 [here]. He further notes that a frequent cause of kidney stones is not drinking enough fluids and, during the summer, people can become dehydrated from sweating. Dehydration, combined with increased iced tea consumption, raises the risk of kidney stones in some persons, especially in those already at risk.

Many people prefer iced tea in the summertime because it is relatively inexpensive, low in calories, and tastes better than plain water. Also, they believe the tea is healthier than other beverages, such as soda or beer on a hot day. However, when it comes to kidney stones, they are not doing themselves a favor with iced tea.

What about drinking hot tea? Certainly, that also contains oxalate, Milner notes, “but it’s hard to drink enough to cause kidney stones.” And, according to the Tea Association, about 85% of tea consumed in the United States is iced.

In a prior news release [here], Milner had noted that more than 2 billion gallons of iced tea is consumed each year in the United State alone. Nearly 128 Americans drink the beverage daily.

It seems that the most kidney-friendly part of a glass of iced tea might be the lemon slice. “Lemons are very high in citrates, which inhibit the growth of kidney stones,” Milner said. However, to quench thirst and to properly hydrate, there is no better alternative than water, Milner advises. Several glasses each day — and flavoring it with lemon slices could be a tasty and wise idea.

Milner also suggests that 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, and eat foods that are high in calcium, which reduces the amount of oxalate the body absorbs.

Who is most at risk of kidney stones? Men are 4 times more likely than women to develop kidney stones, according to Milner, and the risk rises dramatically after age 40. But, postmenopausal women with low estrogen levels and women who have had their ovaries removed also are at increased risk.

Patients with kidney stones, who enjoy iced tea, should mention this to their healthcare provider. It is relatively easy to check if they are producing too many oxalates, Milner recommends. Iced tea is one of those simple pleasures that must be taken in moderation.

Editor’s Note: We were recently notified of an interesting and extensive website,, with the mission of informing patients about kidney stones and treatment options, and to help them take steps to prevent future stones from developing. This non-commercial website was founded by Mike M. Nguyen, MD, MPH, Assistant Professor of Urology at the University of Arizona in Tucson, Arizona. Other contributing urologists include Roger K Low, MD, Manoj Monga, MD, and Marshall Stoller, MD. Our only concern is that, while they state, “The information contained in this website is based on available medical research,” they do not always cite reference sources for facts and information.

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