Like many newspapers across the country, the Juneau Empire ran a front page article on Thursday, June 14 suggesting that vitamin C may damage DNA. This report was probably a source of consternation for anybody taking vitamin C, and they may be wondering if they should stop. However, before you throw out your vitamin C, here are a few things you should know.
The study was performed in a test-tube. Even the author emphasized that it is inconclusive in relation to humans. There are protective mechanisms in human cells as well as other antioxidants present in the body which neutralize the effect of lipid peroxidation, the damaging effect observed.
There are several clinical studies which show vitamin C actually prevents cellular damage, and those studies were conducted in humans and animals, not test tubes. These studies demonstrate that vitamin C protects cells from cancer-causing chemicals such as nitrosamines, cigarette smoke and pollutants.
The notion that vitamin C damages DNA is contradicted by actual clinical research. A study of 200 men published in February 2001 in Fertility and Sterility showed that vitamin C in conjunction with folate actually protects sperm DNA. Since sperm are unprotected and more vulnerable to DNA mutation, this study offers proof for vitamin C's protective benefits against DNA damage.
A large body of research supports the value of vitamin C. The Empire article suggested that there was no such proof. This just isn't true. According to Phil Harvey, Ph.D. and director of science and quality assurance for the National Nutritional Food Association: "The vast majority of all published studies on vitamin C supplementation show an overwhelmingly positive effect on health." A large clinical study which was published in the March 2001 issue of the Lancet is typical. This study of 19,496 men and women demonstrated that mortality rates for all diseases including cancer decreased significantly with ascorbic acid (vitamin C) intake.
It is puzzling that a test tube study with inconclusive results is front page news while a clinical study of nearly 20,000 people published in a major medical journal which shows clear benefits is virtually ignored by the mainstream press. Whatever the reason for that, I agree with Phil Harvey who says: "The real danger here is not from vitamin C, but from sensationalized reports that will cause consumers to stop using a supplement that is clearly beneficial to their health."