Vitamin C May Cause Kidney Stones, Other Problems
Vitamin C has a reputation as a healthful vitamin, associated with sunshine and oranges, but a downside may be kidney stones. It seems that too much of a good thing can turn sour, and high doses of vitamin C may not only cause kidney stones, but other problems as well.
Men have a risk of kidney stones
Before looking at the various health issues associated with high doses of vitamin C, let’s look at the new research from Karolinska Institutet in Stockholm, Sweden. The eleven-year follow-up study evaluated data from 48,850 men ages 45 to 79, and specifically the 436 who developed kidney stones.
Under the leadership of Laura D.K. Thomas, MSc, an investigative team considered data only from men who had taken vitamin C supplements and no others. For comparison, the researchers also repeated their evaluation using data from men who had taken multivitamins only.
The authors found that men who took high doses (about 1,000 milligrams [mg]) of ascorbic acid (vitamin C) daily had a significant twofold increased risk of developing the painful stones. These findings “may not be generalizable to women,” who tend to be at less risk of developing kidney stones, according to the researchers.
The authors also noted that men who used multivitamins did not show the same increased risk of kidney stones. Another important bit of information they shared is that since the risk of kidney stones associated with ascorbic acid may depend on other nutrients consumed at the same time plus the dose, their findings “should not be translated to dietary vitamin C.”
Vitamin C and risks of high intake
Vitamin C is a water soluble vitamin, which means it dissolves easily, is not stored in the body, and is quickly eliminated from the body in the urine. Thus vitamin C should be replaced regularly. The recommended daily allowance for vitamin C is at least 75 mg for women who don’t smoke and 90 mg for nonsmoking men. Both men and women should add an extra 35 mg per day if they smoke.
The tolerable upper intake level of vitamin C for adults is 2,000 mg daily, and most people don’t suffer any significant side effects if they stay below that level. However, there are risks for others.