Akesson said there are no well-documented reasons for anyone to take such high doses of vitamin C. The study doesn't apply to vitamin C that people get from food, and the researchers did find that multivitamin supplements, which don't contain mega doses of vitamin C, didn't seem to boost the risk of kidney stones.
It's not clear if the same possible risk from mega doses would apply to women. The study didn't include women, and they typically face a much lower overall risk of kidney stones than men, Akesson said.
Akesson said more research is needed to confirm the findings, and another expert added that there are not many reasons to take such high doses of the vitamin.
For now, "there are no clear reasons to take supplemental vitamin C if adequate vitamin C is consumed in the diet," said Dr. Gary Curhan, a professor of medicine at Harvard Medical School who has studied kidney problems. "Of note, we have found that higher vitamin C intake is associated with a reduced risk of gout, but this is not sufficient justification to take a supplement."
For more about kidney stones, try the U.S. National Library of Medicine.
SOURCES: Agneta Akesson, Ph.D., associate professor, Karolinska Institute, Stockholm, Sweden; Gary Curhan, M.D., Sc.D., professor, medicine, Harvard Medical School, Boston; Feb. 4, 2013, JAMA Internal Medicine, online
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