What is the Gut Microbiome?

Nothing can change your day like an upset gastrointestinal system―literally! Feeling gassy and bloated can make you want to stay home rather than being around co-workers or friends. Diarrhea can be debilitating. Such unpleasant issues can hijack your day. It’s time to regain control and learn more about our gut microbiomes.

What is my gut microbiome?

Simply put, your gut microbiome is a community of small organisms such as bacteria, fungi, parasites and viruses (trillions of them!) that reside in your large intestine. We typically think of bacteria as being harmful and causing disease. However, some bacteria are incredibly beneficial for maintaining weight, keeping the heart healthy and stabilizing the immune system. For example, some gut bacteria synthesize vitamins and neurochemicals; others aid digestion and strengthen the immune system; some may even guide how the brain develops.

Each gut microbiome is unique

According to the Harvard School of Public Health, each person’s gut contains a completely unique network of microbiota, which is determined by that individual’s DNA. Neuropharmacologist and microbiome expert, Professor John Cryan, says, “For the most part, it is thought that we are sterile while in utero, and as we are being born, as we emerge through the birth canal, we get this handover bacteria. It is like a gulp at birth. Those bacteria are really important for starting the whole process.”

The gut microbiome continues to change rapidly over the first two years of our lives. It diversifies, meaning it starts to contain many different types of microbial species (higher microbiome diversity is considered good for your health). At a young age, the gut microbiome is shaped by microbes in breast milk, other digested foods and the environment. Generally, the gut microbiome stabilizes by the time we are about 3 years old.

However, the microbiome is a living, dynamic environment – the number and type of species may fluctuate daily, weekly and monthly, depending on a number of environmental factors including long-term diet, exercise, stress and the medications we take, such as antibiotics. Your microbiome can change throughout your life, making it either beneficial to health or placing one at greater risk for disease.

How does my gut microbiome affect my immune system? 

The gut microbiome is thought to control how your immune system works. Most of the microbiota in our gut are symbiotic―they live in harmony with the human body. However, there are also pathogenic microbes, which cause disease, in our natural microbiome.

Certain diets, an infectious illness or extended use of bacteria-destroying medications, like antibiotics, can throw off the balance between the symbiotic and pathogenic microbiota, causing dysbiosis or a disturbance in the balance, which can lead to a compromised immune system and a body that is more susceptible to disease.

What else does my gut microbiome affect?

An imbalance of healthy and unhealthy microbes may also contribute to weight gain, type-2 diabetes, rheumatoid arthritis, inflammatory bowel disease, even heart disease. There are still other associations between the gut microbiome and disorders such as anxiety, depression and autism that researchers continue to explore.

Finally, connections between the gut microbiome and how a patient reacts to specific drugs, like chemotherapy, and even to how well a person sleeps are being looked at more closely. Since the gut microbiome plays so many different and vital roles in keeping the human body running smoothly, some health professionals have gone so far as to label it a supporting organ.

The gut microbiome is potentially linked to every aspect of health! Is there a way to test my personal microbiome?

Not yet. Scientists are now beginning to understand the microbiome’s extensive role in health and the broad problems that may result from an interruption to the normal interactions between the microbiome and its host. These same scientists and doctors encourage caution: Much of what is known about gut microbiomes comes from research done on germ-free mice, not humans.

Although it may be some time off, Professor Cryan believes that eventually, doctors will routinely monitor their patients’ microbiomes. “I think personally that bacteria- or microbiome-derived medicine is the future of precision medicine,” he says.

Until that time, knowledge is power. In our next post, we’ll take a closer look at what you can do to encourage a healthy gut microbiome.

What is the Gut Microbiome?