New Study Links Healthy Gut Microbiome to a Longer Life

A new study published in the journal Nature Metabolism found it's never too early to start eating a healthy diet for the sake of our longevity. The study found that the older we get, the more likely we are to age well if we are eating well along the way. This study looked at the gut health of more than 9,000 people. It found that how long we live may be predicted by measuring the health of our gut microbiome.

It’s the latest study to conclude that healthy eating, defined as diverse, mostly plant-based whole foods, with very little or no animal products, determines the balance of bacteria in our gut. The presence of “good” bacteria, fed by high fiber foods like vegetables, fruits, legumes, whole grains, nuts, and seeds, can lead us to live longer lives, according to the research. And this can help us stay well for more of our elder years.

"Gut microbiomes become increasingly unique to individuals with age," the study says and this difference becomes the determining factor when it comes to who lives longest. They looked at three groups within a total of over 9,000 individuals and found that the differences in microbially produced amino acids can predict who will live the longest. These differences are more pronounced the older we get, so people over 80 with the healthiest gut microbiomes will still be alive in four years, which shows that there is a connection between healthy aging and diet.

The identified microbiome pattern of healthy aging is characterized by a depletion of unhealthy bacteria, meaning the older you get, the more likely your gut is lacking the "bad" bacteria associated with a poor diet.

People underestimate the importance of your gut microbiome and overall health

If you grew up thinking your digestive system is simply where food goes for nutrient absorption before the rest is eliminated, you’re not alone. And that’s not untrue, it’s just an oversimplification. It turns out that there’s a lot more to our digestive systems than absorbing vitamins and minerals, and it’s only in recent years that scientists are really beginning to understand the important role of the bacterial colonies that thrive inside our guts.

Human gut microbiomes are a lot like the root system of plants. While plants dig their sinewy roots deep and far into the soil to find nutrients from bacteria and microbes, we produce our own dirt, populating a rich internal “soil” with all manner of bacteria, called the microbiome.

Our bodies build up delicate gut flora colonies depending on what we eat, and whenever we put anything into our mouths, we help determine which bacteria thrive and which ones waste away. The importance of the balance of "good" bacteria to "bad" bacteria is now believed to rule functions far from the gut: The brain, our hearts, the circulatory healthy of our arteries are all impacted by this population in our digestive system. Healthy gut bacteria create homeostasis in the body that drives our digestion, immunity, and overall health.

Building a healthy microbiome starts when you are young and continues as we age

What we eat, and the more we prioritize gut health through consuming healthy foods like leafy greens, vegetables, fruit and nuts, and seeds and cut out animal products and dairy which can be inflammatory, the longer we are likely to live, says the new study, which featured research done at the Institute for Systems Biology (ISB) in Seattle.

The ISB looked at gut health in more than 9,000 people, ranging in age from 18 to 101 years old. The researchers identified a “microbial drift” in healthy 80-year-old study participants. This “drift” moved the participants toward a “unique composition state” that wasn’t present in the subjects with less-healthy gut microbiomes.

The more varied plant-based foods you eat the better for gut health and longevity

The healthier subjects also saw lower levels of common bacteria from the typical American diet that is high in animal fat and inflammatory foods, which led to these individuals having less “unique” gut microbiomes, and these dieters are less likely to live longer than four years after the study began.

Those with the more "unique" microbiomes correlated to the presence of a compound (tryptophan-derived indole) which has also been linked to longer lifespans for mice. These compounds are often a market of reduced gut inflammation — chronic inflammation has been linked to a number of illnesses that can increase the risk of age-related morbidity.

The researchers also noted a correlation between higher levels of healthy gut bacteria and centenarians. In other words, the more diverse and healthy the gut microbiome was, the more likely it was that an individual would live longer.

What this means is the more fruits and vegetables you eat, the more likely your gut bacteria will shift to a healthy and diverse microbiome, producing less inflammation in the body and less overall disease risk, which will be more likely to keep you alive for longer.

Diverse Gut Bacteria, Longer Life

"Interestingly, this uniqueness pattern appears to start in mid-life – 40 to 50 years old – and is associated with a clear blood metabolomic signature, suggesting these microbiome changes may not simply be diagnostic of healthy aging, but they may also contribute directly to health as we age," lead author Dr. Tomasz Wilmanski said in a statement.

"This uniqueness signature can predict patient survival in the latest decades of life."

The gut microbiome changes over time as we age and the researchers found that the healthier a gut microbiome was at the beginning of adulthood, the more likely it was to last and even refine itself given diet patterns or diseases didn’t lead to major changes.

"Prior results in microbiome-aging research appear inconsistent, with some reports showing a decline in core gut genera in centenarian populations, while others show relative stability of the microbiome up until the onset of aging-related declines in health,” Co-author Dr. Sean Gibbons explained.

"Our work, which is the first to incorporate a detailed analysis of health and survival, may resolve these inconsistencies.

"Specifically, we show two distinct aging trajectories – one, a decline in core microbes and an accompanying rise in uniqueness in healthier individuals, consistent with prior results in community-dwelling centenarians; and two, the maintenance of core microbes in less healthy individuals."

The findings suggest placing more effort into maintaining a healthy gut microbiome may be a key contributor to longevity.

You truly are what You eat

Another study published last month in the journal Nature found a connection between changes to the microbiome and an increased risk of Alzheimer’s disease.

“You know the expression, ‘You are what you eat?'” said senior author Jacob Raber, Ph.D., professor of behavioral neuroscience in the OHSU School of Medicine. “This may be part of that.”

The findings are the first to link the gut microbiome health and cognitive and behavioral changes in Alzheimer’s sufferers. The research also identified for the first time a connection between the neural tissue in the hippocampus, an area of the brain affected by Alzheimer’s, and changes in the gut microbiome.

“Microbes may elicit an impact on behavioral and cognitive measures relevant to Alzheimer’s disease via epigenetic changes in the hippocampus,” Raber said. “Or, alternatively, it might be that the epigenetic changes in the hippocampus affect changes in the gut microbiome.”

The Alzheimer’s study mirrors the findings of the longevity study. While we can’t stop aging, the more we prioritize gut health, the better we may ease into old age.

“This suggests that the gut microbiome may not only reflect, but also potentially contribute to, a longer host lifespan,” the ISB researchers wrote. “As our understanding of the aging microbiome increases, monitoring and identifying modifiable features that may promote healthy aging and longevity will have important clinical implications for the world’s growing older population.”

Bottom line: Cut out foods that feed unhealthy gut bacteria such as meat and dairy, junk food, packaged food with added sugar or preservatives. Add more whole plant-based foods in the form of vegetables, fruits, legumes, nuts, and seeds that are minimally cooked or processed. Keep feeding your gut high fiber foods full of healthy probiotics and prebiotics and your gut will take care of the rest.