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Why drinking too much iced tea caused this man’s kidneys to fail

A tall glass of iced tea. (Larry Crowe/AP)

Iced tea is delicious; no one here is denying that. But like with most great things, too much of it can bring about dire consequences.

Such is the story of an Arkansas man who drank so much iced tea that it led him to develop kidney failure. Three Arkansas doctors described the case in a letter published by the New England Journal of Medicine this week.

The 56-year-old man showed up at the hospital in May 2014 with weakness, fatigue and body aches, along with high levels of creatinine, which is used as an indicator for kidney function.

Doctors asked: Do you have a history of kidney stones in your family? No.

What about kidney disease? No.

The questions continued, the doctors write, until eventually "the patient admitted to drinking sixteen 8-oz glasses of iced tea daily."

Yeah, that's a lot of iced tea.  A gallon of it, actually.

Black tea is rich in the food compound oxalate, which had likely clogged the man's kidneys and inflamed them, leading to renal failure and the need for dialysis.

[Half of adults will get chronic kidney disease, model predicts]

"In this case there were oxalate crystals inside the kidney, and that generates an inflammatory reaction," Umbar Ghaffar of the University of Arkansas for Medical Sciences told Reuters. "If that's not resolved it will cause scarring and loss of the kidney tissue. So that's what probably was happening in this patient."

Other foods such as strawberries and spinach are also rich in oxalate. The doctors note that "acute oxalate nephropath" involving over-consumption of star fruit, rhubarb and peanuts has been documented previously documented.

The average American ingests about 150 to 500 milligrams of oxalate daily, the doctors write, which is higher than the 4o to 50 milligrams recommended by the Academy of Nutrition and Dietics.

But at 16 cups of black iced tea a day, the Arkansas patient took in more than 1,500 milligrams of oxalate every day.

Ghaffar told the Associated Press that the man's diabetes wasn't the reason for the kidney failure; the doctor didn't know if he was drinking sweetened iced tea, she said.

"The case presented here was almost certainly due to excessive consumption of iced tea," the doctors write, dubbing it a case of "iced-tea nephropathy."

But other doctors not involved with the case told both Reuters and the AP that the Arkansas case was unusual, and that most people don't approach that much oxalate consumption.

"In this case, the person was drinking huge amounts of oxalate," Harvard Medical School professor Gary Curhan told Reuters. "I would caution people against drinking that much, but drinking a glass or two would not concern me."

So, bottoms up -- to a limit.