Surprising Ways Your Gut Microbiome Changes with Age and Why Change is Good

October 31, 2021

by Cathe Friedrich

One bodily aspect that directly influences your health is your gut microbiome. This is the community of bacteria in your gut, along with their associated microbes and fungi. These organisms are known as “gut flora”, which refers to bacteria that live inside of our digestive tract. Their numbers are astonishing! Around 100 trillion bacteria line the inside of your intestinal tract. It’s a busy environment.

The microorganisms that live in your gut are in a constant state of competition and cooperation with one another. Healthy gut microorganisms help keep the harmful invaders from gaining a foothold in your body by competing for resources and their effects on immune function.

The players that make up your gut microbiome are also involved in extracting nutrients from the food you eat. Plus, this diverse group of bacteria also produces certain vitamins, including vitamin K and some B-vitamins. Research shows these organisms play an intricate role in gastrointestinal function, including digestion and metabolism.

You might wonder how your gut microbiome changes with age, and how that affects your health as the years go by. Researchers believe the gut microbiome plays a role in how people age. Research suggests a more diverse gut microbiome, a microbiome that contains numerous microorganisms, is healthier than one with a limited number of species. Having a diverse ecological environment may give the microbiome the ability to respond to various threats.

Studies show that the gut microbiome of a healthy adult has over 1000 distinct species of bacteria, and the composition of these bacteria can vary widely from individual to individual. Lifestyle habits also play a role in gut microbiome composition. For example, obese people have a less diverse gut microbiome than leaner people, and people who exercise have gut microbiomes that differ from those who are sedentary.

How the Gut Microbiome Changes with Age

Your gut becomes colonized with microorganisms soon after birth and continues to change throughout life. For example, studies show children have higher levels of a bacterial species called Enterobacteria. Another species of bacteria called Bifidobacterium also goes down with age. Lifestyle factors, diet, antibiotic use, physical activity, and even stress can affect the composition of your gut bugs. So, your gut microbiome is quite dynamic, and according to a new study, the changing nature of the gut microbiome may be beneficial for aging.

A Changing Gut Microbiome is a Marker of Healthier Aging

Sometimes change is desirable, and that applies to your gut microbiome. When researchers sequenced the gut microbiome of over 9,000 people of all ages, they found that a changing gut microbiome may be a marker of better health and slower aging. The study showed that people whose gut microbiome composition changed over the decades were healthier than those with a gut microbiome that stayed static. The researchers also found that gut microbiome changes become more pronounced around the age of 40. Changes that start around this time and evolve over time are associated with better health and longevity.

Around 30% of the human microbiome is conserved, meaning the microbes are similar from human to human, but the other 70% varies widely, partially due to different diets and lifestyle habits. A person who eats a plant-based diet, for example, will have a microbiome that differs from someone who eats mostly meat and few plant-based foods. Plants are rich in fiber that helps “feed” beneficial gut microbiome and helps them thrive.

The Gut Microbiome and Metabolites that Affect Health

Scientists have also discovered that certain gut bacteria produce short-chain fatty acids that benefit the intestinal lining. Studies show these short-chain fatty acids, like butyric acid, have an anti-inflammatory effect on the tissue that lines the colon. Plus, they discovered that gut bacteria produce other chemicals, including indoles, that help protect the gut lining and reduce inflammation. Levels of indoles may be a marker for healthy aging.

This study also shows that the gut microbiome continues to develop and change throughout life in healthy people. What’s healthy at one age may not be beneficial at another. Gut microbiomes with more “flexibility” and a greater ability to adapt may be precisely what you need to age more healthily.

How Can You Keep Your Gut Microbiome Healthy?

There’s still much to learn, but here are some ways, supported by science, you can optimize microbiome health:
Avoid taking antibiotics unless you need them.
Replace ultra-processed foods with whole foods and reduce sugar in your diet.
Eat fermented foods, like yogurt, each day.
Add more plant-based foods and fiber to your diet.
Whenever possible, engage in at least 30 minutes of active exercise every day.
Maintain a healthy body weight
Limit alcohol and stop smoking
Manage stress

Take-Home Points:

The gut microbiome plays a key role in health and aging.
Gut microbiome composition changes with age and these changes may be a marker of healthier aging.
A healthy gut microbiome produces chemicals that keep the gut lining healthy.
You can boost microbiome health by eating a diverse diet that includes plant-based foods and fermented foods.
Lifestyle habits, like eating a fiber-rich diet and avoiding antibiotics, help promote gut microbiome health.
There’s still much to learn about the gut microbiome and how it affects health and aging, but it’s clear that it does.

References:

BMC Microbiology volume 19, Article number: 236 (2019)
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