When you think about your gut, you might a imagine your stomach, like a balloon, and your intestines like a series of squishy tubes underneath. You might remember one of those simple, still, anatomical drawings from your middle school health textbook. But if you really want to know what the inside of your gut looks like, it might be more accurate to picture a subway system. There are trains zooming through a network of tunnels, but you also have a bunch of other elements in the mix. People inside the subway cars. Various critters running around the tunnel walls. Storage closets full of half-forgotten supplies.
In reality, your digestive system is an elaborate network that is constantly moving. All of the various elements may seem unconnected and random, but they represent a complex system that works together to use the nutrients you eat and drink to create essential vitamins and chemicals that your body needs. This is your gut's microbiome.
What Is a Gut Microbiome?
To understand the definition of "gut microbiome," it's helpful to break down the term. First, what do we mean by "gut?"
Your gut in this case is your digestive system from the stomach to the intestines. You have a small intestine and a large intestine. Your small intestine is tube-like structure closest to the stomach. The large intestine or colon is the big one at the end. All of those critters running around your intestinal walls are called microbes. The term "gut microbiome" simply describes all of those microbes and the intestinal environment in which they scurry around and do their work. Most of the work happens in your large intestine.
Microbes are mostly healthy bacteria, but fungi and viruses are sprinkled around a bit too. In a healthy gut, trillions of microbes work together to create a balanced system that keeps your body working well. You have 100 times the amount of bacteria in your gut than the cells that make up your entire body.
Every microbiome is as unique as a fingerprint. You get your very first microbes during birth and from experiences like breastfeeding. Then, as you grow as a child and experience the world - even doing things eating cereal off the floor and licking handrails - you gain microbes. As you grow and live your life, your gut microbiome changes and evolves with you.
What Your Gut Microbiome Does for You
It may seem like nonsense that what's happening in your intestines can have any effect on the rest of your body. But more and more research seems to say just that. Your gut microbiome makes needed vitamins like vitamin B and vitamin K and it also helps your immune system fight off disease, protect your heart, and keep your brain healthy.
Educates the Immune System
Experts have found that the bacteria in your gut microbiome help to teach your immune system which organisms are welcome and which ones can hurt you. Your immune system must constantly decide if the various molecules waltzing into your body are something to welcome or something to boot out. Helpful bacteria make this decision-making process more accurate and streamlined.
Breaks Down Food
Your body breaks down the food you eat. Various types of food are broken down differently. Fiber, for example, is a type of carbohydrate that is harder for the body to digest. The way your large intestine breaks down fiber turns out to be very important. When you eat sugar, it gets processed way up near the stomach. But since fiber is more difficult to digest, it makes it all the way to your large intestine. When it gets there, it is broken up into something called short-chain fatty acids (SCFA).
SCFAs have recently gotten the medical community pretty excited because it seems they not only boost your immune system but they can help prevent chronic diseases like diabetes. More studies are needed on this, but if future research proves their helpful activities, SCFAs could be the answer to a lot of problems.
Boosts Brain Health
The microbes in your gut "talk" to your brain through a communication system called the gut-brain axis. First studied in mice, this phenomenon has also been recently demonstrated in humans. "Through electron microscopy---the most intense magnification possible--- bacteria are actually visible going up and down the vagus nerve like a highway," says Dr. Aly Cohen, an integrative rheumatologist. Dr. Cohen says that in this way, your gut bacteria can directly communicate with the brain.
Your gut microbiome influences body systems linked to stress, anxiety, and memory. Researchers have also found early results that suggest a microbiome change could treat neurological disorders like Parkinson's and autism spectrum disorders.
Promotes Heart Health
Some gut bacteria are better for your heart than others. In studies, some researchers have found that after a fecal transplant, patients' heart health improved. A fecal transplant is a medical procedure where feces (and all of those good bacteria) are collected from a healthy person and placed into a different person's gastrointestinal tract. The right gut microbiome can decrease bad cholesterol, increase good cholesterol, and lower body mass. More studies are being done to prove this connection.
The bacteria in your gut release hormones that affect how you tolerate different sugars, how you store fat, and how hungry you are. The better your microbiome, the more "good" hormones it can release into the wild.
What Causes an Unbalanced Gut Microbiome?
As you can probably imagine, an unbalanced gut microbiome, called dysbiosis, can wreak all sorts of havoc in your body. Dysbiosis can be caused by:
This imbalance can contribute to weight gain, irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD). Certain antibiotics can kill off a ton of your microbiome and let a diarrhea-causing bacteria called C. difficile to take over.
Some nasty gut microbes can produce a chemical called trimethylamine N-oxide (TMAO). TMAO has been linked to blocked arteries, which can cause heart attacks and strokes. Okay, that's a lot. So what can you do about it?
How to Improve Your Gut Microbiome
If everyone's gut biome is unique, it can be difficult to imagine that one is "healthier" than another. But experts agree we can change our gut microbiome for the better. While somewhat fixed factors like your genes, your environment, and medications can all affect your microbiome, so can your diet. Consider these steps to get a healthier gut microbiome.
Remove Gut Insults
Avoid food that your gut bacteria doesn't like: artificial colors, preservatives, artificial flavoring. "Try to have fresh foods with the least amount of pesticides," says Dr. Cohen. "You want to make sure they don't kill off your home-grown bacteria."
Feed your gut as much plant-based food as possible. Plants feed the good bacteria and keep them healthy.
"Stress changes the pH of the gut---makes it more acidic," Dr. Cohen says. An acidic gut changes what bacteria can live there. If you're living in a stressful environment all the time, you can lower your good bacteria.
You can build up your gut bacteria by adding probiotics to the menu. Probiotics can be found in fermented foods like:
- Kefir (fermented milk)
- Pickled veggies
- Yogurt with live cultures (like Activia)
Too much of these foods can cause excess gas, so consider yourself (and your housemates) warned. You can also try probiotic supplements, but be aware that supplements are not regulated by the Food and Drug Administration (FDA) the same way medications are, so use caution when choosing one. Your gut also loves food high in fiber. Processed foods can throw your microbiome out of whack, so be careful to limit how much you eat each day.
Remember, your microbiome is unique to you so no one thing above will fix your IBS or keep you from getting heart disease. Speak to your healthcare provider about adding new bacteria friends to your gut, and you can run any over-the-counter probiotics by them too. With all that your gut microbiome tries to do for you, it deserves to be pampered!