By Jennifer Geiss

As a former fitness trainer, I embrace the notion that “you can’t out-exercise a bad diet”. This is true because one can’t overestimate the power of food when it comes to weight loss, healing and happiness.   

Believe it or not, almost all symptoms and illness that people struggle with are connected to the health of the digestive system. This includes mental health!

The gut-brain connection is a concept that many still question because it’s not obvious that the brain would be affected by the health of the gut. Therefore, I suggest thinking of it as the immune system-brain connection.

Our immune system’s job is to protect us from harm. Whether that’s from the food we take in to the germs that we pick up throughout our day. Did you know that 70% of the immune system lives in the digestive system? The immune system and its ability to do it’s job is directly connected to allergies, energy, headaches, mood, pain and even weight loss.

There is only so much the immune system can handle before it becomes taxed so we want to make sure that it’s as strong as it can be. When the immune system is busy fighting molecules of toxic food or defending you from seasonal pollen, it won’t have much left when we get exposed to that stomach bug going around.

In order to have a properly functioning immune system, we must have a healthy digestive system. Because nearly three quarters of our body’s immune system lives in the digestive tract, it has the most profound impact on overall health out of all the internal organs.

Maintaining a healthy balance of gut flora (the community of bacteria and genes living in the gut) is one of the best ways to build and enhance digestive health and thus the immune system. The composition of gut flora differs from person to person and depends on age, diet, environment and use of antibiotics.

Here are several interesting things about gut health to consider.

The Gut-Brain Connection

There is a direct connection between the gut, mood and behavior. In fact, the gut and the nervous system are created from the same tissues during embryonic development. Studies have shown that healing the gut has a dramatic effect on mood, anxiety, and even attention.

The serotonin found in the body is created mostly in the gut. Serotonin is a neurotransmitter manufactured in the intestines and the brain. In fact, 90% of serotonin is found in the gut and it is responsible for maintaining a stable mood. The highest concentrations of serotonin (which influences mood) are in the gut! Serotonin deficiency often leads to depression, so it makes sense that we want our serotonin factory to be in the best shape possible.

We all talk about ‘gut feelings’, but few of us really appreciate the amazingly strong connections between the brain and the digestive system.

Stress, Anxiety and Digestive Stress

When we experience stress or anxiety, what we’re actually experiencing is an activation of the fight-or-flight response, which is designed to make it easier for us to escape physical danger. This is useful if we have to run away from a tiger (in the actual jungle) or speeding car (in the urban jungle).

However, the fight-or-flight response consumes a great deal of our brain’s resources, so to compensate it slows down systems that aren’t as necessary at that dangerous moment, such as the muscles involved in digestion. Normally, since the fight-or-flight response is only supposed to be temporary, we would not notice that our digestion was impacted. But because anxiety is often a chronic issue, we’re left with a digestive tract that is not functioning correctly because the brain is prioritizing escape from a dangerous situation.

That can cause several different issues and often leads to constipation, diarrhea, gas, bloating, and traditional indigestion.

Gut-Brain connection, healthy foods


What to do to optimize the immune system so that we can have optimal mental health:


  1. Optimize digestion by eliminating inflammatory foods. Some foods that are highly inflammatory and pretty easy to avoid are processed food and junk food. Take it a step further with eliminating sugar, soy, corn, gluten and dairy. As a food sensitivities coach, I see so many benefits from eliminating these foods and you may be surprised yourself!


  1. Supply your body with vitamin-rich organic produce, organic plant protein and pasture-raised animal protein. To minimize exposure to toxins, opt for organic as much as possible. You can go to to see the updated list of the top 12 toxic foods based on chemical exposure, which is called the Dirty Dozen.


  1. Eat healthy fats such as avocados, coconut, nuts, eggs from chickens on pasture and wild-caught fish. Fat actually makes up 70% of brain tissue – which means that your brain literally runs on fat. Healthy fats also help with the absorption of vitamins and minerals, cushion vital organs, keep you satiated, lower inflammation, and so much more.


  1. Add probiotic-rich foods and a probiotic supplement to nourish the healthy gut flora in your digestive tract. When we take in probiotics, we ingest healthy bacteria that make their way to the gut lining and displace unhealthy bacteria that may be accumulating due to digestive distress, food sensitivity, or infection. My favorites are sauerkraut, kimchi, tempeh and stevia-sweetened kombucha.


  1. Eat slowly without multitasking and chew your food well. It’s not only what you eat, it also on how you eat. Focusing on the ‘how’ will drastically improve the absorption of nutrients from your food. It will also give you more energy because your digestive system won’t have to work so hard.


  1. Make time for adequate sleep. To get a good night’s rest, I recommend getting to be bed at a decent hour without stimulation of TV or electronics. Ideally sleeping from 10pm to 6am will give you the best quality sleep. As far as late-night eating, do your best to finish your last meal of the day at least 3 hours before you go to bed. You’ll sleep more soundly when your body doesn’t have to focus on digesting food.


  1. Find movement that you enjoy. As you exercise, the smaller muscles of the digestive system are stimulated. The digestive muscles need to be toned and fit to digest your food properly. Living a sedentary lifestyle makes for a sluggish digestive system, so it makes sense to move more so that both fitness and digestion are optimized.

I hope that you find these pointers helpful because if you love your gut, it will love you back!



Jennifer Geiss

Jennifer Geiss is a certified health coach specializing in food sensitivities and allergies. With a passion for food that tastes great and satisfies cravings, her mission is to heal the body while living a delicious life! Jennifer’s website is Check out her private Facebook group ‘Food Sensitivities Coaching with Jennifer Geiss’.