Your inner universe: Learn more about the microbiome
You are not alone in your body. Billions of microorganisms live in and on you, and they have more power over your health than you might think. In the gut alone exists the most densely populated habitat on Earth, with over 100 billions bacteria living in coexistence with you. This is known as the microbiome.
What exactly is the microbiome?
The microbiome is the collective term for all the microbes (bacteria, fungi, viruses, etc.) that live in and on the body. Microbiomes exist in the mouth, the vagina, and on the skin, but the largest and most well-known is the one in the gut, better known as the gut flora.
Your microbiome consists primarily of bacteria, with the greatest concentration found in the large intestine. Most of these bacteria are what we call beneficial bacteria. They transform the food you eat that cannot be digested into various compounds — including short-chain fatty acids — which are sent back into the body. In doing so, they help influence both your health and your mood.
Different foods also increase or reduce specific bacteria. What you eat therefore has an enormous impact on the state of your microbiome, which is why it is important to feed these tiny helpers.
How it develops: Your microbiome is unique
But food is not the only factor that shapes your microbiome. In fact, the microbiome varies greatly from person to person.
The microbiome develops during childhood, beginning at birth, when bacteria from the mother's various microbiomes — both the vaginal and the gut microbiome — reach the baby's mouth and colonize the gut. Babies born by caesarean section receive fewer of these bacteria from the outset.
From there, the child's gut is gradually exposed to different bacteria depending on whether the child is breastfed, has siblings, grows up in the city or the countryside, comes into contact with animals and nature — and of course, what diet they receive.
All of this contributes to shaping and creating your personal microbiome, which is entirely unique to you.
What do the microbes do in the body?
One of the most important functions in the development of the microbiome is building the immune system.
You may have heard that it is important for children to be exposed to a wide range of bacteria to strengthen their immune system, and that is entirely correct, as approximately 80% of the immune system resides in the gut. There, it is constantly exposed to foreign microbes that it must identify as either beneficial or harmful.
The immune system is also one of the pathways through which the gut communicates with the brain, known as the gut-brain axis. The gut and brain are connected through, among other things, the vagus nerve, part of the parasympathetic nervous system, which regulates bodily functions during sleep and influences food intake, energy balance, and inflammation.
The vagus nerve also plays a role in digestion. When stimulated, it improves our digestion — affecting how the intestines massage and move food along, how efficiently nutrients are absorbed, and how regular and comfortable bowel movements are.
This two-way communication means that the microbiome also influences our mental wellbeing. Read more about the gut-brain axis here.
When the microbiome falls out of balance
Although every microbiome is unique, there are nonetheless indications of when a microbiome is in balance.
A healthy microbiome can be thought of as a rainforest, with great diversity and a good balance between many different species. If the rainforest becomes dominated by one particular species, you may be missing out on a number of beneficial species and their advantages, and you risk the microbiome falling into imbalance, also known as dysbiosis.
Dysbiosis is commonly seen when there is low diversity, a reduced presence of beneficial bacteria, or an overgrowth of harmful bacteria.
Several factors can disrupt the microbiome:
Poor diet (e.g. processed and ultra-processed foods and a lack of fiber)
Antibiotics (particularly broad-spectrum antibiotics, which kill not only harmful but also beneficial bacteria) Hear DTU professor Patrick Munk explain what antibiotic resistance is in our podcast.
Stress (which inhibits the vagus nerve and affects digestion)
Overuse of hand sanitizer and cleaning products (as we need exposure to other people's bacteria)
Should this occur, it is fortunately possible to restore the balance.
How to support your microbiome
The balance of your microbiome — and how you feel — is a collaboration between you and your gut bacteria.
What you eat helps feed your gut bacteria, and if you provide them with the right nutrients and create the most optimal conditions, they will deliver beneficial functions back to you.
The beneficial gut bacteria's favorite foods are:
Fiber-rich foods such as vegetables, seeds, nuts, grains, and legumes
Fermented foods such as kimchi, kefir, and kombucha
Polyphenols — natural colorful plant compounds, so aim to fill your plate with as many colors as possible
Pre- and probiotics — supplements containing live bacteria and their nutrients are an effective way to boost your microbiome
But there are other things your gut will thank you for as well:
Regular exercise
Spending time in nature frequently
Enough good-quality sleep (a minimum of 7 hours)
Avoiding stress
Eating slowly and chewing your food at a relaxed pace
Small changes can make a big difference for you and your microbiome.
Learn more about your microbiome
If you are curious to take a closer look at your own gut health and find out which bacteria you are carrying around, you can gain insight with a microbiome test from Unseen Bio.
You can also listen to the podcast Mikrobiomet ("The Microbiome"), where we dive deeper into the microbiome with a range of experts who discuss the many aspects it influences.
Be sure to read our other blog posts covering topics such as the impact of different foods on the gut flora.
