Many people have the goal of living a long, healthy life—and scientists may have uncovered the secret to doing just that.

A new study, which was published in the journal eBioMedicine, analyzed the DNA and lifestyle of seven centenarians (i.e. people who are at least 100) to try to figure out how they’ve lived so long. The researchers discovered that people in the 100+ group have highly functional immune systems that have fought off and recovered from a range of illnesses.

While the study is small, the researchers said in a statement that it’s the largest single-cell dataset of centenarian subjects to date. There were 89,739 centenarians living in the U.S. in 2021—nearly double as many as there were two decades ago, according to data from the United Nations.

So, is having a robust immune system in older age the key to living longer? Here’s what we know.

Why might a strong immune system help you live longer?
It’s important to note upfront that the study didn’t prove that having a strong immune system helps you live longer—it simply found that people who live past 100 have strong immune systems. “It’s unclear if this is the driver of extreme age or the consequence of it,” says Scott Kaiser, M.D., a geriatrician and Director of Geriatric Cognitive Health for the Pacific Neuroscience Institute in Santa Monica, Calif. However, there are a few things worth exploring here.

One is that your immune system tends to become less robust as you get older, says lead study author Tanya Karagiannis, Ph.D., senior bioinformatician at the Center for Quantitative Methods and Data Science, Institute for Clinical Research and Health Policy Studies at Tufts Medical Center.

“With age comes changes in our immune systems, including in their function and cell make-up, and these changes can lead to aging-related diseases,” she says. “Many centenarians experience delays in the onset of aging-related disease and this suggests the presence of an elite immunity that continues to remain highly functional even at extreme old age.”

But centenarians also seem to come into contact with their fair share of pathogens, Karagiannis says. “Our findings suggest that centenarians experience a greater exposure to infections and harbor unique, highly functional immune systems to deal with these exposures, allowing to reach extreme old age,” she says.

At a very basic level, too, having a strong immune system means that your body is better able to fight off infections that could be serious—and even deadly, says Thomas Russo, M.D., chief of infectious diseases at the University at Buffalo in New York. “One of the leading causes of death is infection,” he says. “We’re doing better in this era of antibiotics and a variety of supportive therapy, but we’re still quite imperfect in terms of trying to manage serious infections.”

“If someone has an immune system that behaves like that of a much younger individual, they’re much less likely to die from infections,” Dr. Russo continues. “While that’s not the only factor in reaching a ripe old age, it is an important one.”

How to support a healthy immune system

A lot of how your immune system performs comes down to genetics, Dr. Russo says, and the latest study findings support that. “Our study suggests there are gene expression changes of the immune system specific to centenarians,” Karagiannis says.

You can’t really give yourself an immune system like a centenarian, but you can “artificially bolster” it to ensure you’re as prepared as possible for pathogens that might come your way, Dr. Russo says. “That means making sure you’re up to date with all the vaccines that we recommend with the appropriate timing,” he says. “It’s certainly better than not getting vaccinated.”

It’s also important to see your healthcare provider on a regular basis and, if you’re a group that high risk for developing serious or lethal complications of infections, to have a low threshold for calling your doctor, Dr. Russo says.

Dr. Russo stresses the importance of maintaining a healthy weight, exercising on a regular basis, eating a healthy diet, and getting at least seven hours of sleep a night. “All of the things that are good for your health overall will potentially help your immune system and longevity,” he says.

“Practicing mindfulness, self-care, and stress management are important, too,” Dr. Kaiser says. “It’s unbelievable the evidence that shows that regular meditation can have a significant positive impact on your immune system.”

Ultimately, Karagiannis says, “we do not have the answer to how to live longer.” However, that may be coming. “Our findings can provide a foundation to explore potential drivers of extreme old age that could lead to the discovery of healthy aging therapeutics,” she says.