Iced Tea Danger: How Much Is Too Much?

Recently, a man went into kidney failure after drinking too much iced tea. Could you be at risk? How much iced tea is it safe to drink? Nutrition Diva explains.

Monica Reinagel, MS, LD/N, CNS
4-minute read
Episode #329

I know that many of you saw the headlines last week about a man who went into kidney failure after drinking too much iced tea.  How do I know? Because I suddenly started getting emails from worried listeners, asking how much iced tea one can safely drink. 

The case, which was reported in a letter to the editors of the New England Journal of Medicine, involved a middle aged man who went to the hospital in pretty bad shape and eventually ended up on dialysis. The doctors were initially perplexed about the cause of the kidney failure but eventually concluded that it was "almost certainly due to excessive consumption of iced tea."

Iced Tea: How Much Is Too Much?

The guy reported drinking about a gallon of iced tea every day - which is a considerable amount but by no means unheard of. Those of you who live in the southern United States, for example, know what I'm talking about. If everyone who drinks a gallon of iced tea a day were to end up in kidney failure, there wouldn't be enough dialysis machines in the Northern Hemisphere to handle the demand. 

In fact, that's precisely why this case ended up in the New England Journal of Medicine: it was a surprising and unusual event. Nonetheless, the doctors speculate that tea consumption could be an under-recognized factor in kidney disease. They encouraged other doctors to ask patients with unexplained kidney problems about their tea consumption. 

Why Would Tea Hurt Your Kidneys? 

Black tea is rich in natural compounds called oxalates, which are found in lots of otherwise healthy foods, such as spinach, rhubarb, bran cereals, and chocolate. Oxalates bind with calcium, which reduces the amount of calcium your body can absorb from high-oxalate foods. As long as these foods aren't the only source of calcium in your diet, this isn't likely to be an issue in terms of your bone health. But if those calcium/oxalate crystals accumulate in your kidneys, it can cause kidney stones, inflammation, and even kidney failure.

See also: Can Drinking Tea Cause Kidney Stones?


How much is too much? The average person takes in between 150 and 500 mg of oxalates per day - and people whose diets are high in vegetables, whole grains, soy, and other legumes probably fall toward the top of the range.

The patient in this unusual case was getting around 1500 mg per day, just from his tea - and that was clearly too much for his kidneys.  That doesn't mean it would be too much for your kidneys. Some people are simply more prone to forming kidney stones than others. In fact, general population studies have found no relationship between the amount of oxalates in the diet and the risk of kidney stones. 

See also: Can Drinking Tea Cause Iron Deficiency?


About the Author

Monica Reinagel, MS, LD/N, CNS

Monica Reinagel is a board-certified licensed nutritionist, author, and the creator of one of iTunes' most highly ranked health and fitness podcasts. Her advice is regularly featured on the TODAY show, Dr. Oz, NPR, and in the nation's leading newspapers, magazines, and websites. Do you have a nutrition question? Call the Nutrition Diva listener line at 443-961-6206. Your question could be featured on the show.