This release is available in French.
For more than 40 years, the prevailing explanation of why we get old has been tied to what is called oxidative stress. This theory postulates that when molecules like free radicals, oxygen ions and peroxides build up in cells, they overwhelm the cells' ability to repair the damage they cause, and the cells age.
An industry of "alternative" antioxidant therapies -- such as Vitamin E or CoQ10 supplements in megadose format --has sprung up as the result of this theory. However, clinical trials have not shown that these treatments have statistically significant effects.
And now researchers at McGill University, in a study published in the February issue of the journal PLoS Genetics, are calling the entire oxidative stress theory into question. Their results show that some organisms actually live longer when their ability to clean themselves of this toxic molecule buildup is partially disabled. Collectively, these molecules are known as reactive oxygen species, or ROS for short.
Dr. Siegfried Hekimi of McGill's Department of Biology, said most of the evidence for the oxidative stress theory is circumstantial, meaning oxidative stress could just as easily be a result of aging as its cause.
"The problem with the theory is that it's been based purely on correlative data, on the weight of evidence," explained Hekimi, McGill's Strathcona Chair of Zoology and Robert Archibald & Catherine Louise Campbell Chair in Developmental Biology. "It is true that the more an organism appears aged, whether in terms of disease, or appearance or anything you care to measure, the more it seems to be suffering from oxidative stress".
"This has really entrenched the theory," he continued, "because people think correlation is causation. But now this theory really is in the way of progress."<
|Contact: Mark Shainblum|