Could smells affect your lifespan? Female fruit flies rid of the ability to smell food outlive their peers.The sense of smell may be linked to the cellular ageing process in many other organisms--even people.A link has recently been found between sensory experiences and lifespan in both worms and flies.For example, Scott Pletcher, a biologist at the University of Michigan, found that eliminating   fruit flies' ability to smell enabled them to live nearly 20 percent longer than flies with an intact sense of smell. Pletcher's team reasoned that food smells were the ones most likely to affect ageing, as nutrition and longevity are known to be linked in many organisms.To test the idea that food odors affect lifespan, Pletcher's team eliminated flies' ability to smell carbon dioxide, which is produced by some fly foods.They left the rest of the smelling system intact. This intervention had no effect on male flies, but the females lived 30 percent longer than normal.Pletcher thinks eliminating the ability to smell CO2may deprive flies of information about food availability.This could signal to cells that food is scarce, causing processes that promote survival.Indeed, his team found that the CO2-insensitive female flies stored extra fat and that both males and females immune to CO2were more resistant to stress than normal flies.Pletcher isn't sure why the change in his fruit flies only affected the lifespan of the females, but he suggests that females may simply be more sensitive to the odor of CO2. A smell or taste that stretches lifespan in humans could be a potential preventative for age-related disease, he adds.Although in fruit flies it appears to be the smell of CO2that affects ageing, he says that an analogue in humans might be a smell or taste linked to human food--or a lack of it.Matt Kaeberlein studies ageing at the University of Washington in Seattle. He cautions that we don't know whether ageing and smell are linked in mammals.But " we definitely undergo physiological changes in response to smelling food--I'm getting hungry just thinking about it--so I think it's possible." The purpose of the study by Scott Pletcher is to   _  .
show there is the best way to make lifespan longer tell us we should eliminate our smell ability to live long show the sense of smell can affect the cellular ageing process explain female fruit flies without ability to smell odor can live longer