Men who regularly take vitamin C supplements are at a higher risk of developing kidney stones, new data suggests.
The study, published in JAMA Internal Medicine, finds that regular consumption of vitamin C supplements – in the form of ascorbic acid – at a typical 1000 mg per tablet dose are twice as likely to develop kidney stones as men who do not take any dietary supplements.
However the 11 year follow up study, led by Led by Dr Agneta Åkesson from Karolinska Institutet in Sweden found no association or increased risk of kidney stones in those consuming multivitamins – which contain lower levels of vitamin C.
Åkesson and her team said while the findings do not prove the vitamin itself triggers stones to form. But researchers said that because there are no clear benefits tied to taking high-dose vitamin C, people who have had stones in the past might want to think before taking extra supplements.
"As with all research, the results should be corroborated by other studies for us to be really sure," said Åkesson. "Nor can we say anything about whether women run the same risk as men.”
“But given that there are no well-documented benefits of taking high doses of vitamin C in the form of dietary supplements, the wisest thing might be not to take them at all, especially if you have suffered kidney stones previously, " she said.
The research new study findings are based on data from a large population-based study of men from the Västmanland and Örebro areas of Sweden.
Åkesson and her colleagues identified 23,355 men, all of whom had no history of kidney stones and consumed either no dietary supplements or supplements in the form of vitamin C only. These men were followed for 11 years.
During this 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. This analysis was then repeated for men who took only multivitamins.
The results of the study indicate that men consume take vitamin C supplements along – typically at a dose level around 1000 mg per tablet – are twice as likely to develop kidney stones as men who do not take any dietary supplements. However, the regular use of multivitamins was not found to be associated with the risk of kidney stones.
Discussing the findings, the researchers suggested that both the dose received and the combination of nutrients with which the vitamin C is ingested could play an important role in the risk. For this reason, the observed increase in risk does not apply to a normal dietary intake of vitamin C from fruit and vegetables, they said.
Source: JAMA Internal Medicine
Published online ahead of print, doi:10.1001/jamainternmed.2013.2296
"Ascorbic Acid Supplements and Kidney Stone Incidence Among Men: A Prospective Study"
Authors: Laura D. K. Thomas, Carl-Gustaf Elinder, Hans-Göran Tiselius, Alicja Wolk, Agneta Åkesson