The saying “you are what you eat” means more as you get older.

With age comes wisdom, maturity … and, unfortunately, inflammation. Indeed, aging is characterized by an increase in the level of low-grade, chronic inflammation in the body, a widely known phenomenon known as “inflammaging.” It can be felt in the body — as early as age 50 — as fatigue, lethargy and even depression, explains Jason Tetro, visiting scientist at the University of Guelph and author of The Germ Files.

But a new study points to the significant role that gut microbiota — the complex community of microorganisms that lives in the digestive tract — plays in controlling inflammation, and suggests:

The gut and immune system “cross-talk” and, in turn, can have an impact on longevity.

What does this mean? According to the study, eating well could be key to keeping age-related inflammation under control, preventing diseases such as diabetes, heart disease, cancer and a weakened immune system.

“With poor nutrition as one of the drivers of inflammation, it’s now being recognized that improving diet might be a way to slow, control or maybe even reverse the inflammaging process,” says Philip Calder, professor of nutritional immunology at the University of Southampton and a lead author of the study, recently published in Ageing Research Reviews.

Eating foods that improve our immune system response can significantly reduce the risk of chronic diseases and conditions.

The analysis suggests that living longer is closely linked to a reduction in the type of inflammation that comes with age. The good news: In the elderly it can be “manipulated” by nutritional interventions, says Calder. One way: adding omega-3 fatty acids, probiotics, prebiotics, antioxidants and polyphenols into the diet.

Calder believes there are different levels of communication between the gut microbiota and the immune system, and a big part of these conversations involves the gut “educating” the immune system early on in life and then maintaining immune function as we get older. “If the microbiota changes so that more pathogenic organisms take hold, then the communication with the host immune system breaks down, as well as the links with metabolism and the brain,” he says. This can be especially serious in the elderly, Calder adds.

The most surprising thing about age-related inflammation is that it seems to happen naturally, Tetro says. “At the molecular level, some of the biological machinery tends to go awry,” he says. “When this happens, there is a cascade effect”; a change inside a cell could compromise the entire immune system. This leaves the elderly susceptible to infections and chronic diseases.

So how do we get a jump on things before they become a problem? Both Tetro and Calder believe a Mediterranean diet, which involves primarily plant-based foods, such as fruits, vegetables, whole grains, legumes and nuts, could be a helpful defense. The effects of cellular changes can’t be reversed, but we can “mitigate their potential to cause harm by keeping the rest of the immune system in balance,” Tetro explains.

Just how important is diet? Although the mechanism behind each inflammation-related disease differs, Tetro explains that eating foods that improve our immune system response can significantly reduce the risk of chronic diseases and conditions, from stroke and osteoporosis to Parkinson’s, Alzheimer’s disease and cancer.

Indeed, you are what you eat — but this becomes even more relevant as those wrinkles start appearing.