Vitamin C supplements linked to kidney stones

New research from Karolinska Institutet shows that men who take vitamin C supplements regularly run a higher risk of developing kidney stones. The study, which is published in the scientific periodical JAMA Internal Medicine, did not however observe an increased risk between kidney stones and multivitamins - which contain lower concentrations of vitamin C. The research is based on data from a large population-based study of men from Västmanland and Örebro counties, who were monitored for 11 years. A total of 23,355 men were identified who had no history of kidney stones and who took either no dietary supplements or supplements in the form of vitamin C only. During the study period, 436 of the participants developed kidney stones that required medical attention. The researchers then compared the risk of kidney stones in vitamin C-takers with that in men who did not take any supplements. The analysis was then repeated for men who took multivitamins. The results of the study indicate that men who take vitamin C supplements (typically 1000 mg per tablet) are twice as likely to develop kidney stones as men who do not take any dietary supplements.