Human lifespans are longer than ever, but longevity alone doesn't guarantee good health. Many people are now asking not only "How long can I live?" but "How well can I live?" While lifespan refers to the total number of years from birth to death, healthspan is the portion of those years spent in good health.

Diet plays a major role in determining how well we age. Scientists have long known that both the amount and the type of nutrients we consume influence aging. Using the microscopic worm Caenorhabditis elegans, Professor Spang's team showed that specific RNA molecules found in food can improve the worms' health in later life. "These molecules prevent the formation of harmful protein aggregates that are typically linked with aging and disease," says Spang. The results of their study were published in Nature Communications.

How diet shapes aging

As organisms age, their ability to remove damaged or altered proteins declines. These proteins can accumulate and form toxic clumps within cells, which are thought to drive the aging process and contribute to diseases such as Alzheimer's, Parkinson's, and various muscle disorders.

The researchers discovered that a balanced diet supports longer healthspan and that certain dietary components offer protective effects. The worms mainly consume bacteria that contain double-stranded RNA molecules. "These dietary RNAs are absorbed in the gut and activate quality-control mechanisms to protect from cellular stress," explains Emmanouil Kyriakakis, the study's first author." This low-level stress essentially trains the body to cope with protein damage more effectively."

Diet-dependent mechanisms slow cellular aging

Diet activates autophagy -- a cellular "clean-up" process that degrades and recycles damaged proteins. This mechanism reduces harmful protein aggregation and thus slows down cell aging. "We were surprised to find that the gut communicates with other organs," says Kyriakakis. "We observed protective effects not only locally, but also in muscles and throughout the whole organism."

Healthier aging -- even in worms

Overall, the worms exposed to a balanced diet were more active and healthier in old age. "The dietary-RNA species elicit a systemic stress response that protects the worms from protein aggregation during aging," says Kyriakakis. "thereby extending their healthspan."

The findings confirm that diet strongly influences health in old age. "Specific food components can stimulate the body's own protective mechanisms," adds Spang. "So, a little stress can be good for you." Whether individual nutrients can also spark beneficial effects in humans -- and potentially help prevent age-related diseases -- remains to be investigated. But it's certainly conceivable. What is clear already: What we eat can shape the way we age.