A gram a day went with more kidney stones in men, not women
Across 40,536 men and 156,735 women followed 11 years, 1000 mg a day or more went with a 43% higher rate of first stones in men. Vitamin C from food tracked with nothing.
What the study found
1000 mg of vitamin C a day tracks with stone risk in men, not women
This is a supplement finding, not a food finding. Across 40,536 men and 156,735 women followed for eleven years, 1000 milligrams a day or more went with a 43% higher rate of first kidney stones in men and no raised rate in women. Vitamin C from food tracked with nothing in anyone.
The caveat · Supplement takers may differ anyway
People who take a gram of vitamin C a day may differ from those who do not in ways a diet questionnaire misses, so this is a pattern rather than a cause. Hardly anyone ate more than 700 milligrams from food, which leaves the food comparison untested at the doses where the supplement finding appears.
What we don't know
People who take a gram of vitamin C a day may differ from those who do not in ways a diet questionnaire misses, so this is a pattern rather than a cause. Hardly anyone ate more than 700 milligrams from food, which leaves the food comparison untested at the doses where the supplement finding appears.