Sirtuins are part of a survival mechanism that helps us cope with difficult times. Researchers have known for a while that cutting back on calories, so long as all the basic nutritional requirements are met, seems to extend the lives of many animals. There’s some evidence that it also works in humans, although this is not proven.
Researchers believe that the stress of a restricted diet affects the genes that regulate sirtuins. The cells then produce more of these repair proteins to protect themselves. In the process, the life of the animal is extended.
But under normal conditions, when there is no threat, the activity of the sirtuin genes declines after the reproductive years, said Leonard Guarente, a professor of biology at the Massachusetts Institute of Technology. The cells lose their ability to repair themselves and we start to age.
And that is one the reasons we become susceptible to a host of diseases, he said. Theoretically, if we can find a way to boost these proteins, we should be able to combat the major causes of death and disability among older people, like diabetes, heart disease, cancer, and Alzheimer’s.
Some researchers even think it might be possible to turn the clock back by preventing the reduction of activity in sirtuin genes in the first place. That way the body could keep repairing itself as well as it does when we’re young.
“There is a chance that aging is reversible,” said Sinclair, but there are many barriers to doing so.
You may have seen ads for a supplement called resveratrol that claim to already be delivering such results. Resveratrol, a substance found in red wine that boosts the activity of sirtuins, has been shown to increase the lifespan of yeast, flies and obese mice. But there’s not yet any evidence that it benefits humans or that it’s safe.
But scientists are using resveratrol to study the potential of targeting sirtuins, though many are also working on more powerful drugs.
No one knows what kind of side effects sirtuin-targeting drugs might cause. If you extend the lives of cells, some researchers fear that you may increase the risk of cancer. Cancer is caused by mistakes in our DNA that build up over time and eventually cause a cell to grow uncontrollably. It’s also possible that the extra sirtuins will be able to keep up with the repair work on our DNA. They could prevent those DNA mistakes from developing into cancer, reducing the risk. No one knows yet which way it will go.
“One way of fighting the war on cancer is to fight the war on aging,” said Kenyon.