Lemons and other citrus fruits contain chemicals that can help prevent against the development of kidney stones, says John Milner, a urology expert from the Loyola University Chicago Stritch School of Medicine.
"Lemons are very high in citrates, which inhibit the growth of kidney stones," Milner said. "[Real] 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 made the comments in the context of warning people to drink enough water during the hot summer months. Insufficient fluid intake is the most common cause of kidney stones, which occur when mineral crystals form in the kidneys or the ureters, which connect the kidney and the bladder. For those who are reluctant to drink enough water because they want something with more flavor, Milner suggested adding lemon slices.
People at risk of kidney stones definitely should not drink large quantities of ice tea, he said.
"People are told that in the summertime they should drink more fluids. A lot of people choose to drink more iced tea, thinking it's a tastier alternative," Milner said. "However, in terms of kidney stones, they're getting it going and coming. They're actually doing themselves a disservice."
Iced tea contains high levels of the chemical oxalate, which encourages the development of kidney stones.
"For people who have a tendency to form kidney stones, it's definitely one of the worst things you can drink," he said.
People who are concerned about kidney stone should also consume lower levels of chocolate, rhubarb, nuts and spinach, all of which are high in oxalates, Milner said, as well as meat and salty foods.
Kidney stones are four times more likely to occur in men than in women, particularly men who have reached the age of 40.