The microbiome and the gut-brain connection are well known, but what exactly they are is not always entirely clear. You may know that some bacteria are involved and that the "gut" plays a part, but the details beyond that can be a bit hazy.
The microbiome may sound complicated, but it's actually a fairly simple concept to understand. However, what is not simple is its role in many different aspects of our health. Science is only scratching the surface of the many ways that the bacteria that live in our gut affect our health, and the sooner we understand them, the better we'll get out of it.
What is the microbiome?
We are referring to the bacterial environment of the gut, specifically the large intestine under normal circumstances. Some people also consider the bacteria that live in the mouth to be part of the gastrointestinal tract and, therefore, part of the microbiome.
The bacteria in the microbiome include thousands and thousands of different types of species, not just one or two types. There is no way to determine the exact number, but it is known that there are millions of bacteria in the intestine.
For years, it was thought to act like a "fingerprint," with each person having their own unique set of bacteria within their microbiome. Now, doctors know that the microbiome is a dynamic and constantly changing environment . In fact, it's so dynamic that the microbiome right now could be very different from what it will be an hour from now.
What factors affect it?
Factors that affect and change include everything from how much sleep you get to your stress levels to what medication you take to what food you eat.
Lunch time
All kinds of things shape our gut bacteria, but the food we eat is probably the most important.
Processed and refined foods, such as meats, sugars, and alcohol, can have a negative effect. After just five days of eating a diet high in animal fat and low in fiber, people experienced an increase in bile-tolerant bacteria , which are linked to inflammatory bowel disease, in a study published in Nature in January 2014.
So switching to a high-fiber diet with complex carbohydrates results in a greater diversity of gut bacteria, more fiber-loving bacteria, and lower markers of colon inflammation, according to a June 2018 study in Cell Host and Microbe.
Probiotics
Probiotics are live microorganisms that we absorb and are meant to be "good" bacteria in our intestines. These can be found in both supplements and food.
Foods like kimchi , kombucha , yogurt, sauerkraut , and tempeh contain live bacteria that are beneficial to our gut.
Most people will benefit from a high-fiber diet that includes probiotics, to encourage the growth of good bacteria. But pay attention to how your body responds to those foods: Some people, for example, are sensitive to FODMAPs, a food group that includes many fruits, vegetables, and grains. If you notice that a particular food or food group is causing you excessive gas or bloating, you can avoid it.
Prebiotics
Prebiotics encourage the growth of friendly gut bacteria, thus acting as food for the "good" probiotics in our intestines.
The microbiome lives off undigested food in our intestines, so the things we can't digest and absorb become food for the bacteria in the microbiome. Depending on what we eat, some species of bacteria in the microbiome will flourish more than others because we have given them what they prefer.
Insoluble fiber is especially important for stimulating the growth of good bacteria in the microbiome. To get more prebiotics, add these foods to your diet:
- Oatmeal
- Asparagus
- Bananas
- Lion teeth
- Leeks
- Onions
- Woman
- Beans
- French Fries
Other factors
Almost every action in your life also affects your microbiome, from how much you sleep to how you manage stress. For example, sleep deprivation was linked to negative changes in the microbiome, while adequate sleep was linked to a more diverse microbiome environment, according to an October 2019 study in PLOS One.
Genetics may also play a role in shaping the bacteria that make up the microbiome, according to a November 2014 article in the journal Cell, although it is still unclear to what extent, and how much we can change it with our own actions.
What is the gut-brain connection?
The microbiome is also connected to mental health, but a better term than "gut-brain connection" is "brain-gut-microbiome connection." The brain can affect the gut and modify bacterial behavior in the gut, and vice versa.
For example, bacteria in your gut can release chemicals that change neurons in your brain, which then release chemicals like serotonin, which can affect your mood. We know that this connection extends to bacteria and bacteria to us.
But while we know that the connection works both ways, that our brain can affect our gut and our gut can affect our brain, the details of this connection aren't quite clear yet.
A pilot study, published in April 2018 in the Journal of Neurogastroenterology and Mobility, found a link between irritable bowel syndrome (IBS) and subjective well-being, but how mood and gastrointestinal symptoms affect each other needs further research.