People are talking a lot about the gut lately. Are you wondering why gut health matters? Is it worth your while to make changes in your diet and lifestyle that will make your gut more healthy?
Let’s find the answers. In this article I will describe some of the really important functions of your digestive system. Your gut might be affecting not only how comfortably you digest food, but also your energy levels, your immune system, and other aspects of your health.
Read on to learn why your digestive tract is possibly the most important system in your body.
Nutrients come in through your gut.
Putting food into your mouth and swallowing it does not automatically make it a part of your body. First, the nutrients must be digested and absorbed. The inside of the gut is actually considered to be outside your body. Think of the gut as an airport hallway where travelers wait to pass through customs and get into a country.
Anything that enters the body through the mouth must pass through a single layer of cells called enterocytes that lines the gut. These tightly joined cells prevent harmful substances from getting in. However, nutrients enter the gut easily if your digestion is healthy.
The digestive system breaks foods down into the smallest forms possible. Saliva, stomach acid, enzymes and bile all work together to do this job. You need all of these things in place before nutrients can make it into your body.
Toxins exit through your gut.
At some point, you are going to swallow toxic substances or harmful bacteria. They enter your body, or they pass all the way through and out the other end. Remember how the gut is actually outside the body? This comes in real handy when there is something in there that might harm you.
The normal metabolic processes produce some toxins. Your liver filters these out and sends them to the gut for elimination. Otherwise they might build up and begin to create problems.
Think of it like taking out the garbage. If you don’t do that regularly, your house can get really clogged up with harmful and unsightly bags of trash. Your body’s normal trash pick-up – you guessed it, pooping – should happen at least once a day.
Your immune system is centered in the gut.
About seventy percent of your immune system is actually located in your gut. Lymph nodes are embedded all throughout the walls of your intestines. They recognize and protect you from microscopic foreign invaders.
You are putting things from the outside world into your gut every day, and your body has to sort out what is safe and what is not. Many specialized cells help with this, including antibodies like sIgA, B-cells, T-cells, dendritic cells, toll-like receptors, and other cytokines.
Your gut also has physical barriers to keep out invaders. A mucus membrane prevents bacteria from accessing the gut lining. Strong stomach acid destroys harmful bacteria that might be in your food.
Your gut affects brain health.
Gut health matters because it is directly connected to your brain. The gut produces all of the major neurotransmitters that affect mood and brain function. They include GABA, dopamine, serotonin, acetylcholine and norepinephrine. Your gut produces over eighty percent of your body’s serotonin.
The vagus nerve is the longest nerve cluster in your body, beginning at the brain stem and running all throughout your GI tract. Messages run in both directions along this nerve, from the brain to the gut and also from the gut to the brain.
Hormones and neurotransmitters produced in the gut can reach the brain via the vagus nerve, cross the blood-brain-barrier, and affect food intake, appetite, emotional and cognitive health, and conditions like depression and PTSD(1).
The link between the brain and the gut is evident when we look at people who are suffering from irritable bowel syndrome (IBS). Over seventy percent of people with this condition have mood or anxiety disorders that require psychiatric help. Healing the gut can sometimes alleviate these conditions (2)(3).
Gut microbes protect your health.
You have about 3-4 pounds of bacteria living in and on every nook and cranny of your body. This is your microbiome. Nearly every organ system has its own microbiome. We have known about the bacteria that live in our mouth or skin for a long time. Now we are finding that even organs like the kidneys and lungs contain a microbiome.
There is about 150 times more DNA in the microbiome than there is in human body cells. In fact when you take your microbiome into account, less than half of the DNA contained in your body is human. An astonishing fact is that you have around 22,000 functional human genes. Your microbiome has at least three and a half million genes.
Here are some of the ways that microbes keep your gut and your whole body healthy.
- Microbes modulate your immune system. They help your immune cells to recognize what is a threat, and what is a part of your own body.
- The bacteria in your gut break down plant fibers that you cannot digest. They digest these fibers and produce short chain fatty acids (SCFA), an important fuel for the cells of your gut lining.
- As you learned already, microbes make neurotransmitters which are able to affect your brain health.
- Gut microbes synthesize small amounts of essential vitamins. These include thiamine (B1), folate, biotin, riboflavin (B2), and panthothenic acid.
Your gut allows nutrients to enter your body, and gets rid of toxins that might harm you. The digestive tract is ground central for your immune system. The vagus nerve connects your gut and your brain, and produces many of the neurotransmitters your brain needs.
Your gut microbiome performs many of these tasks. Gut microbes also digest plant fibers and produce fuel that keeps the cells of your gut lining strong. They even produce some of the essential vitamins that you need.
Now that you know why gut health matters, how do you make sure to keep it that way?
Here are some of the things that you need for a healthy gut.
- stomach acid
- digestive enzymes
- muscle movements in your gut
- beneficial gut bacteria
Would you like to learn more about all of these parts of your digestion? Join my eight week online program, Simply Good Digestion.