Patient drank 16 glasses a day, which probably contributed to health issues, researchers suggest
THURSDAY, April 2, 2015 (HealthDay News) — After conducting a kidney biopsy on a 56-year-old man with unexplained kidney failure, doctors discovered numerous oxalate crystals in his kidney tissue. Black tea is a significant source of oxalate, and the man acknowledged drinking 16 glasses of iced tea every day. The researchers reported the man’s case in the April 2 issue of the New England Journal of Medicine.
“There are reports about kidney stones related to high oxalate intake attributed to tea, but to our knowledge there are no reports of biopsy-proven nephropathy associated with excessive consumption of iced tea,” report coauthor, Alejandra Mena-Gutierrez, M.D., of the University of Arkansas for Medical Sciences in Little Rock, told HealthDay.
The researchers said that kidney problems caused by high oxalate levels may be an under-recognized reason for kidney failure. In the United States, the average intake of oxalate per day ranges from about 150 to 500 milligrams, the researchers wrote. That’s higher than the recommended intake, which is under 40 or 50 mg per day, they noted.
Black tea has about 50 to 100 mg for every 100 milliliters (about 3.4 ounces), the researchers said. The man with the failing kidneys was drinking more than 1,500 mg of oxalates a day, they estimated.
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