Coke, coffee and iced tea are the southern holy trinity of non-alcoholic beverages. We use the word “coke” generically to include any brand of soft drink, whether actual Coca-Cola or regional favorites such as Barq’s Root Beer and Dr. Nut, may it rest in peace. Likewise, tea in the South is generic for iced tea, though the trend is to specify sweetened or unsweetened.

While favorite coffee blends and soft drink brands vary by state and region, iced tea is iced tea. Various tea-brewing processes yield more or less the same end product served across the South. John Egerton had it pegged: “Iced tea is too pure and natural a creation not to have been invented as soon as tea, ice and hot weather crossed paths.”

We consume iced tea all year long with a surge in warm months. Whether sweetened or unsweetened, our tea equals ice cubes in a large glass preferably topped with a sprig of mint from right outside the kitchen door. A summer day without iced tea is as unnatural as a day without a daily newspaper.

More and more drinkers prefer unsweetened iced tea, a sometimes difficult to acquire taste for Southerners raised on the sweetened variety. For years I assumed unsweetened iced tea was akin to oxygen. Sweetened tea has caloric concerns, but the consumer can control sugar content in a glass of tea, unlike soda beverages.

How much iced tea is too much? Unsweetened iced tea has always been below the radar for the food police focused on regular and diet soda drinks, salt and anything fried. But science has no sacred cows, and earlier this year a case report in the prestigious New England Journal Of Medicine put iced tea lovers on notice. Too much of anything, including iced tea, isn’t a good idea.

Three kidney specialists working at a VA Hospital in Little Rock wrote about “A Case of Iced Tea Nephropathy.” Their patient was a 56-year-old man with fatigue, weakness and body aches. Laboratory testing showed the man had new onset kidney failure with some different findings from the typical renal failure caused by diabetes or hypertension.

One of the eagle-eyed physicians did what medical students are taught but what rarely gets done these days: A look at his urine specimen under a microscope showed abundant crystals easily identifiable as calcium oxalate crystals. Such a finding is classic for persons poisoned by drinking ethylene glycol, the main ingredient in antifreeze that sometimes shows up in bootleg whiskey. Too much Vitamin C or a binge on tropical star fruit can also cause dangerous oxalate levels in the urine.

One by one their patient denied exposure to all the known culprits associated with high urinary oxalate levels. In the end it all boiled down to iced tea – too much iced tea. He had been drinking a gallon or so of iced tea daily made from off-the-shelf common black tea. His kidney biopsy confirmed the diagnosis. The tissue sections were chock full of oxalate crystals.

The authors suspect “oxalate nephropathy may be an under recognized cause of renal failure.” They recommend asking patients with renal failure about their diet, especially if the urine contains oxalate crystals but no protein.

“We often see patients with oxalate kidney stones,” says local nephrologist Dr. Frank Cruz. “We tell them to cut back on high oxalate content foods like nuts, rhubarb and star fruit. We give them a food list. Excess Vitamin C turns to oxalate in the body and can aggravate kidney stones. But I have never seen a situation where iced tea caused kidney failure. Black tea is high in oxalate, but all the water that goes along with the tea usually flushes out all the excess oxalate unless there is some underlying kidney problem.”

As though to underscore that all things should be consumed in moderation – just remember that even applies to iced tea. 

Case reports in medicine

Written communications or letters involving what happened to a single patient are low on the totum pole of academic prestige in medicine. Even so, case reports are a time-honored way of reporting individual observations and even disease outbreaks.

The New England Journal of Medicine has become one of the most prestigious medical journals published today. Dozens of dispatches in the 1800s describe cases of yellow fever, cholera, influenza and other maladies from New Orleans. A brief mention in 1850: “A patient was admitted to the Charity Hospital, in New Orleans, who had, the night previous, melted lead poured into one of his ears while he was asleep.”

In recent years case reports from New Orleans have become as rare as hens’ teeth. A parasitologist at the Tulane School of Public Health and Tropical Medicine authored the last in 1995. It was a letter describing an 11-year-old boy with meningitis caused by a parasite traced to a snail. On a dare the boy ate a live snail plucked from a New Orleans street harboring a parasite that was his ticket to the hospital. He survived.

The last case report from LSU in the journal was in 1978. The ageless Dr. Charles Sanders and colleagues reported on a young man who developed muscle breakdown and kidney failure after extreme exercise. This was one of the early reports on what was then termed exercise-induced myoglobinuria. Sometimes a single case report will lead to identification of other similar cases. Some conditions thought to be rare turn out to be not all that uncommon after all. Hopefully this isn’t the case with iced tea and kidney failure.