A topic that’s vitally important to our overall health is gut health. Many patients come to my office not even realizing that this is an issue. When we think about the gut and the digestive system, it’s the place that inputs from the outside world enter our body and then are absorbed and assimilated into our body, usually in the form of food. But other things come in too. As a result, somewhere between 70-80% of the immune system is centered around the gut.

When talking about the gut pathway, you have your esophagus, then to the stomach, and the stomach empties into the small intestine and finally through the large intestine. Most of your nutrient absorption occurs in the small and large intestine. As a result, this is where the immune system recognizes foreign compounds that have entered the body. Because of this, there are many immune system cells right outside the lining of the gut. One of the risks of having the gut flora out of balance is that the immune system starts to overreact to things that it shouldn’t be reacting to. This can lead to a variety of different autoimmune diseases and reactions. When talking about the lining of the gut and in the colon, there’s a single cell wall layer that separates the inside of the intestine from inside of our body. That single layer is designed to absorb nutrients in their smallest form. For example, carbohydrates are broken down into glucose molecules or fructose molecules. Proteins are broken down into amino acids, and fats are broken down into fatty acids. They’re broken down into very small molecules so our bodies can adequately absorb them. The molecules go through the cells of the gut wall, and then it’s presented into the bloodstream around the gut. When our gut functions correctly, our immune cells recognize those molecules as fuel, and know what to do with them. When the gut starts to be dysfunctional, or if there’s damage to the lining of the gut, instead of the cells being closely opposed forming an effective gut lining so that only the properly sized particles can go through the cell, gaps form in the tight junctions between the cells, and larger molecules are admitted.

When we have these gaps, the items that are getting absorbed from the gut are moving into the body, both at a higher rate and in different forms than they would come through the properly functioning cell wall. Larger particles that might have otherwise been excreted are now able to get in. These foreign molecules can also damage cells damaging function. When these larger particles that might not be completely broken down get past our gut lining, and are presented to the immune system, the immune system doesn’t recognize them as food or fuel and recognizes them as something foreign that it needs to get rid of. This causes the immune system to ramp up, it calls in its helpers and they start to make antibodies and react to these molecules.

This is typically how food sensitivities develop. There’s some damage to the lining of the gut, then for example, some molecules from corn get through the gut lining and now your immune system starts reacting to corn or whatever that foreign food object might be. The problem is, in nature, proteins are very similar. If you are reacting to a substance that looks an awful lot like some of your thyroid cells, now your immune system is not only attacking what it thinks was abnormal from the gut, it starts to attack your thyroid gland or maybe at your joints with something like rheumatoid arthritis, or possibly even your brain in the case of Alzheimer’s disease as shown in studies on mice. Gut health is vitally important to controlling the balance of immunity in the body. So you’re not getting too much overreaction and inflammation, but yet you’re still getting enough to fight off infections, bacteria, or mutating cells in the body.

The things that can damage that lining of the gut are many. A lot of the toxins in our environment, pesticides, herbicides, that we may be ingesting in our food may damage the gut. Stress can damage the gut. When cortisol levels are too high or if you have to take a steroid like prednisone for example, that can damage that lining of the gut, also if you are sensitive to certain foods, this all can damage the lining of the gut. If you have celiac disease or a sensitivity to gluten, that can damage the cells in the gut and then lead to other food reactions in the gut. Certain medications, things like antibiotics, non-steroidal anti-inflammatory drugs like ibuprofen, sometimes even long-term use of some of the acid blocking medications like Prilosec or omeprazole are things in the category that can damage the gut. There’s some evidence in studies that even birth control pills can damage the gut lining. Eliminating those medications can be very helpful, but if you do have to take one of those medications it can be important to be doing additional things to help balance and support on the other end.

A critical part of gut health is the microbiome. For those who took biology in high school, you may remember talks about different types of biomes, or environments, where different types of organisms live. Our gut has a vast and diverse microbiome. It’s called a microbiome because it’s all microbes, biologic organisms like bacteria, viruses, yeast and fungi. All these organisms live normally in the gut, and the diversity and balance of those microorganisms living in the gut are critical to our health and survival. In fact, there are trillions of bacteria in the gut, probably even more than there are cells in our body. Our gut and that gut microbiome has evolved to be critical to how we maintain our health.

Anything you can do to improve the diversity and health of your microbiome will positively affect gut health. When we have a great diversity of good bacteria in the gut, they make a substance called short chain fatty acids. These substances help heal and repair our gut. Doing things to enhance good bacteria like taking probiotic, or eating fermented foods can be helpful. Even more important is feeding those good bacteria with the prebiotics needed to help them grow to thrive and flourish on their own. The more diverse prebiotics, a great diversity of fruits and vegetables and plant based products in the diet, the more diverse your microbiome will be. If our diet is limited to chicken nuggets, pizza and burgers, your microbiome is not going to be very diverse and this can lead to health issues. A goal to work toward over the course of a week– eat 30 different kinds of plants. I’m talking about beans, whole grains, fruits, and vegetables. The more variety you have, the better your health will be, and the better the gut will be able to heal itself.

The microbiome is a great topic of research right now. Scientists are researching the connection between the microbiome and many different kinds of illness. We’re finding connections between the microbiome and the development of diabetes, the development of heart disease, development of Alzheimer’s disease, all this beyond just how the gut can affect the risk of autoimmunity. An example from the literature– scientists transplanted the microbiome of an obese mouse, into a thin mouse, and the thin mouse becomes obese and vice versa. When you put the microbiome of the thin mouse into the obese mouse, the obese mouse becomes thin. Certainly in the coming years we’re going to find that the gut is vital to the management and prevention of chronic illness.

The gut and the brain are also very connected. There are bacteria in the gut that can influence things like anxiety and depression. A recent example that comes to mind, scientists in a lab setting took the gut bacteria from mice that displayed anxiety, and put that gut bacteria into normal mice not exhibiting this behavior, and the normal mice began to exhibit anxious behavior. So the gut and the brain are very intimately connected. We’re only now beginning to understand how deeply. Everyone has had butterflies in their stomach when they’re nervous about something, or we say when we get a gut feeling about something, These systems are very intimately connected, but no one thinks to look at the gut when they’re trying to address anxiety, depression, memory problems, concentration problems. What’s going on in the gut may have a lot more to do with many of the symptoms, imbalances, chronic illnesses and things that we develop that we attribute to other body systems like the heart of the brain or the lungs. I feel it’s very important to start thinking about gut health and how to improve it.


So, in closing, in addition to the dietary fixes discussed, such as increasing vegetable intake to increase the microbiome diversity and health. We should also be aware of the items to limit our intake of. Sugar and refined carbohydrates are very harmful to the microbiome. While we’re adding diversity, we need to be cognizant of cutting out processed foods from the diet and focusing on whole foods that are going to improve our gut health.

 In addition, there are supplements that can help improve gut health. Things like L-Glutamine, aloe vera, extract, prebiotic fiber. Fixes like adding a digestive enzyme if you’re not breaking the food particles enough. A high-quality fish oil rich in Omegas is helpful, vitamin D. There’s a huge variety of supplementation that can help heal the gut lining and improve the digestive function of the gut. Adding probiotics to the gut is a staple that most everyone should engage in.

But truly, the foundation is in avoiding the things that damage the gut, and focusing on proper nutrition and putting the right things into the gut to promote a healthy microecology.

Lauren Loya MD

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