Microscopic worms exposed to the diabetes medication metformin live longer because the drug makes them produce more free radicals according to a new study that has implications for human health and advocates of “anti-aging” antioxidants.
The study by researcher Wouter De Haes and colleagues showed that the active pharmaceutical ingredient (API) extends the lifespan of Caenorhabditis elegans by increasing the amount of oxygen radicals the roundworms produce in their cells.
He told us that: “Metformin seems to increase the production of reactive oxygen species by interacting with the so called electron transport chain in the mitochondria, the organelles responsible for energy production in each cell.”
“This,” he continued “combined with an increase in mitochondrial respiration caused by metformin, will increase the production of reactive oxygen species.”
The finding that reactive oxygen atoms increase longevity runs contrary to the popular free radical theory of ageing , which characterises them as harmful chemicals that damage DNA and cause cells to degrade over time.
De Haes said that, while radicals do cause such damage, the results of the study indicate they also have beneficial long-term effects thanks to a process known as mitohormesis in which proteins known as peroxiredoxins trigger a protective mechanism.
“These proteins [peroxiredoxins] are highly sensitive to oxidation by reactive oxygen species. After oxidation, peroxiredoxins are activated and can in turn activate other proteins, eventually leading to the induction of several mechanisms that increase stress defence and longevity.”
One study is not likely to overturn the free radical theory or indeed the billion dollar antioxidants sector that has grown up around it, but the results do fit with other recent research that has called into question the role that reactive oxygen atoms play in aging.
While De Haes was cautious about extrapolating his findings and making claims about the active pharmaceutical ingredient’s potential impact on human lifespan, he did say he is “hopeful” that metformin might work similarly in humans.
“Metformin has been associated with reduced cancer risk in humans and can increase lifespan in mice indicating that it seems to have a positive effect on longevity in mammals as well.”