There was a time when the word “microbiome” was considered too science-y for the average American. But suddenly the word has gone mainstream, popping up in the news and implicated in all kinds of conditions, from depression to type 2 diabetes. There’s even a microbiome diet!

So, is this just the latest fad, or should we be listening? And what exactly is the microbiome?

Your Own Personal Ecosystem

Your microbiome is an ecosystem made up of the trillions of microbes that live on every surface inside and on your body. Your microbiome is as unique to you as your fingerprint, and it affects your health in ways that scientists are only beginning to discover. (You can read a more detailed definition here.)

The New York Times has called the study of microbiomes “red hot,” and in 2016 the Obama administration announced the launch of the National Microbiome Initiative to encourage funding for the study of the bugs that are living in and on our bodies.

One reason for the interest in microbiomes is the burgeoning field of genetic analysis. It’s now possible for researchers to identify many of the microbes in your body. Particularly intriguing to scientists are gut bacteria — the beneficial microbes that are thriving along the lining of your intestinal tract.

What Microbes Do in Your Body

These gut microbes aren’t just passing through. They have important jobs to do to keep you healthy. For instance, gut bacteria:

• Are essential to digestion
• Produce vitamins K, B7 (biotin), and B12
• Help regulate appetite
• Help control inflammation
• Help control cholesterol
• Stimulate the immune system
• Are involved in production of 90% of your serotonin, the feel-good neurotransmitter

An imbalance in the mix of bacteria living in the intestinal tract or a shortfall of certain microbes has been linked to obesity, depression, and chronic diseases, from heart disease to diabetes.

How Your Microbiome Ages

By the time you were three years old, your digestive tract, especially your colon, was home to a community of diverse bacteria. Some of those microbes got there from your mother as you passed through her birth canal. If you were breastfed, you accumulated even more. And you picked up some bugs from your environment as you played with other kids, petted the cat and made mud pies in the dirt. (Yes, you can be too clean for your own good! )

As a healthy adult, the bacterial ecosystem that is unique to you is well established and fairly stable. However, those bugs can take a beating when you take antibiotics to squelch an infection or eat a high-sugar, low-fiber diet of processed foods.

By the time your hair turns gray and your joints begin to stiffen, your microbiome has changed. In your senior years, your microbiome bears little resemblance to the one of your youth.

Although researchers haven’t pinpointed exactly how aging changes your intestinal flora, they do know that certain factors can be damaging.  

• Your intestinal tract has its own nervous system with as many nerve cells as your spinal cord. It’s not clear how the gut and the bacteria within it interact with the brain, but scientists know that chronic stress disrupts the communication. Experts suspect this unhealthy mix of gut bacteria contributes to depression. Also 95% of serotonin, the feel-good hormone, is produced in the digestive tract in a process that’s stimulated by healthy gut bacteria.
• A high-fat, high-sugar diet leads to an overabundance of a type of bacteria that is usually lower in healthy adults. Such a diet is also likely to be low in fiber. Since bacteria in the colon need fiber for a process that creates inflammation-fighting fatty acids, insufficient dietary fiber indirectly interferes with the body’s ability to fight inflammation, the culprit behind many diseases of aging. Finally, a diverse mix of healthy bacteria requires a diverse diet, and as we age into our 60s and 70s and lose some of our sense of smell and taste, our diets tend to grow monotonous.
• A study of the intestinal microbiota of older adults in Ireland found that whether or not a senior lived in a long-term residence was linked to changes in the balance of gut bacteria and measures of inflammation. The scientists also learned that those people who lived in a long-term residence or short-term rehabilitation facility had a high proportion of one common type of gut bacteria. Those seniors living at home had a high proportion of another type. The follow-up study showed that it took only a year in a long-term residence for this shift to occur.
• Gastrointestinal conditions that often occur in seniors such as diverticuli, decreased saliva production and tooth loss also alter gut bacteria.

How to Keep You Microbiome Healthy As You Age

Here’s what you can do to boost the number and type of healthy bacteria in your belly:

• Eat a diverse, low-fat, high-fiber diet, such as the Mediterranean diet. Researchers have found that a diverse diet makes for the most diverse population of gut microbes in seniors.
• Make small portions of fermented foods part of your daily diet. These foods help replenish your gut bacteria and include sauerkraut, yogurt, buttermilk, kefir, soft cheeses, pickled vegetables or kimchi, and tempeh.
• Practice stress relief — whatever technique is comfortable for you. Try progressive muscle relaxation, meditation, or listening to moderately loud, instrumental music.
• Exercise daily. It not only helps relieve stress; animal studies show that physical activity contributes to a robust population of gut bacteria.
• Brush and floss regularly. Keeping your gums healthy and holding on to your teeth as you age allows you to eat a chewy and diverse, fiber-rich diet that includes prebiotics. These undigested carbohydrates in leeks, onions, garlic, asparagus, and bananas feed your gut bacteria.
• Don’t take antibiotics unnecessarily. And, if you do, replenish your gut bacteria with fermented foods and possibly a probiotic supplement. Clinical trials show that taking a probiotic with the antibiotic reduces the risk of antibiotic-associated diarrhea.

Here’s to your microbiome!

Read “What You Need to Know About Probiotics” on SeniorPlanet.org