Researchers at the Karolinska Institute in Stockholm, Sweden have found that men who take high doses of Vitamin C may have a higher risk of developing kidney stones than those who do not.
“This is because some of the vitamin C absorbed by the body is excreted in urine as oxalate, one of the key components of kidney stones,” explained study leader Laura Thomas, who stressed that men with a history of kidney stones should consult their doctors before taking high doses of the supplement.
Thomas’s study tracked more than 22,000 middle-aged and elderly for 11 years. The current analysis included 907 men who said they took regular vitamin C tablets and more than 22,000 who didn't use any supplements, according to the Daily Mail.
Swedish supplements, like those the study participants would have taken, typically contain about 1,000 milligrams (mg) of vitamin C per tablet. This is far more than the FDA recommended daily allowance of 75-90 mg
Of the vitamin C users, nearly 3-1/2% developed kidney stones for the first time during the study, compared to approximately 2% of non-supplement users.
It should be noted, however that the study does not apply to Vitamin C obtained through eating fruits and vegetables, important for maintaining bone and muscle health, as well as preventing severe deficiency which can cause scurvy.
For more information, readers can check out Thomas’s study, which was published online in the journal JAMA Internal Medicine.