The Relationship Between Gut Health & Your Overall Well-Being
When you really think about it, our bodies are absolutely incredible. We breathe without thinking about it, our heart rates adjust to the needs of our bodies automatically, our nervous systems react to dangers before we are aware of them, and we are able to use our brains to wonder and create. And, while we often think of our bodies as a bunch of different and unrelated parts, the reality is that all of the parts are interconnected and interdependent - they all need to be functioning well in order for us to be and feel healthy. And, so much of the health of these other systems (cardiovascular, reproductive, nervous, digestive, respiratory, immune) is dependent on the health of our gut. In fact, what is going on in our guts impacts every system in our bodies, including our brains.
What is a Healthy Gut?
When we talk about a healthy gut, what does that actually mean? While we need a healthy and functioning mouth, esophagus, and stomach, what most people are talking about when they refer to a “healthy gut” is actually having a diverse microbiome in our intestines. Our intestines are filled with bacteria - up to two pounds of bacteria live in our intestines and colon! The microbiome refers to the grouping of these bacteria in the gut. And, all of the different strains of those little bugs have specific functions (some beneficial and some harmful). Just like people, the different strains of bacteria like different foods. I am sure you have heard of probiotics and prebiotics (and we will talk more about them later), but probiotics refer to the bacteria themselves and prebiotics refer to the food the bacteria need to thrive. So, we want to strive for a balance of probiotics and make sure we eat plenty of prebiotics that support the healthy bacteria because having an optimal diversity of that bacteria is of the utmost importance to the healthy functioning of all of the systems in our bodies.
When we have an imbalance of bacteria in our guts, this is called gut dysbiosis, which simply means that we have an overgrowth of “bad” or opportunistic bacteria and an undergrowth of “good bacteria”. That may not seem like a big deal, but it is actually pretty problematic, I’ll explain.
Good vs Bad Bacteria
There are certain strains of bacteria in our guts that are associated with obesity and certain strains that are associated with metabolic health. When we have a highly diverse microbiome (a multitude of varying bacteria), we have more energy and lower weight. In fact, in studies cited by the NIH, the microbiome from an obese person has been implanted into the intestinal tract of a person of healthy weight and that person gained weight without changing their caloric intake. The only thing that was different was the makeup of the microbiome! So, the conclusion is that the bacteria play an important role in deciding how our bodies use the food we ingest - how many calories are extracted from it and how the nutrients in the food are utilized.
A second danger to our gut, and therefore our overall health, is inflammation. Seventy percent of our immune system is in our gut. When you think about it, that is super smart and pretty cool. Our bodies are designed to keep us alive. When we eat something, we are literally ingesting it into our bodies. There is no other activity that occurs multiple times a day that potentially exposes our bodies to so much danger. If that thing we ingest is poisonous, our bodies need to respond quickly and effectively so we don’t die. They do this by mounting an immune response to manage the danger and heal the damage caused. And, a large part of our bodies’ immune response is inherently inflammation. So, when we eat something that our body doesn’t recognize as food and doesn’t know what to do with (think chemicals, food additives, processed oils), it launches an immune response and that means inflammation. Nothing good happens when our intestines are inflamed!
First off, the inflammation messes with the balance of bacteria so our microbiome is thrown off (see above for the problems that causes!). Secondly, inflammation can lead to permeability of the intestinal lining, also known as leaky gut. This means that small openings occur in the lining of the gut that allow for small particles of things that should be eliminated through the digestive tract to now go directly into the bloodstream. As you can imagine, this leads to a whole host of problems throughout the body in places like in the thyroid, the liver and the brain. A third consequence of gut inflammation (and dysbiosis, by the way) is disruption of the vagus nerve. This nerve is also known as the gut-brain connector and carries information between the two. When this communication is disrupted, a whole host of problems occur that impact both our physical and mental well-being.
Healthy Gut Bacteria
Interestingly, there is a built-in antidote to inflammation when we have a healthy microbiome. It turns out that, when we feed our healthy bacteria the things that they like (prebiotics), they create short-chain fatty acids (SCFAs) that protect the gut by reducing inflammation, increasing energy in the cells of the gut, and decreasing visceral fat.
Hormones and Neurotransmitters
A third common problem associated with gut dysbiosis has to do with our hormones and neurotransmitters. It turns out that a great deal of the neurotransmitters that influence sleep and mental health are produced and/or stored in our guts. Let’s start with serotonin. Serotonin is a neurotransmitter that plays a key role in many important elements of sleep and emotion regulation. When serotonin is low, people feel more anxious and more depressed, have trouble sleeping, and digestion can be off. And, as it turns out, there are specific gut bacteria strains that are needed to stimulate cells in our guts to produce and secrete serotonin. If we don’t have those strains of bacteria, we don’t make enough serotonin.
Additionally, serotonin is necessary for the production of melatonin (also made in the gut). As most of us know, melatonin is essential for sleep because it regulates our circadian rhythms. But, it is also important for regulating blood pressure, body temperature, cortisol levels and immune function. So it seems that we need to have a healthy gut microbiome to create and secrete serotonin to help regulate our mood, sleep and digestion, and to make melatonin. To add salt to the wound, when we don’t get good sleep, the prevalence of the “bad” bacteria that is more common in people with obesity increases! A yucky, vicious cycle for sure!
How to Improve Your Gut Health
But, there is hope! We can change our gut microbiomes just by eating differently!
First of all, you want to focus on eating a variety of whole foods and avoid highly processed foods and added sugar whenever possible. Choose foods that are sold in the perimeter of the grocery store (fruits, vegetables, meats, nuts, eggs, whole fat dairy); avoid foods that come in boxes and will last for weeks or months on your shelves. If possible, choose foods that are in season - this will ensure that you are eating a variety of foods throughout the year.
Add in some foods that are high in probiotics (strains of the “good” bacteria). These include yogurt (plain, whole fat, Greek is the best), kefir, kimchi, sauerkraut, pickles and kombucha. With all of these, however, be careful of added sugars. The opportunistic bacteria LOVES sugar so we are supporting the growth of the unhealthy strains of bacteria when we eat added sugars!
Next, we want to make sure we are feed ing the “good” bacteria the things that they love. This is what we call prebiotics. Some great prebiotic foods are apples, green bananas, chicory root, oats, garlic, onions, leeks, asparagus and cacao. If you’re a dark chocolate lover, you are lucky!
Fiber and Gut Health
Lastly, we want to make sure we are getting enough fiber. Fiber is super important for a lot of reasons, but one amazing thing it does is help regulate our blood sugar. I can talk about that more at a different time, but for right now, let’s stick with what fiber does to help keep our guts healthy! There is soluble fiber that combines with water in our gut and forms a gel-like substance that protects the integrity of our gut lining. Soluble fibers are found in avocados, sweet potatoes, Brussels sprouts, peas, black beans, broccoli, apples and flax seeds (not an exhaustive list). And, we have insoluble fiber which works as a bulking agent in our guts and helps to trigger satiety so we know when to stop eating. Insoluble fiber is found in berries, beans, okra, spinach, cacao, apples, walnuts and almonds (also not an exhaustive list).
Do you see how this all fits together? Are you as amazed by our bodies as I am? Isn’t it cool that simply by being mindful about what we eat, we can have an impact on so many aspects of our physical and mental health?
Let’s start feeding those healthy bacteria in our guts so we can live our best lives!