You probably know that the immune system is a complex and important system that works to protect you from potentially harmful illnesses like the flu, but did you know that the health of your digestive system influences how well your immune system works? About 70% of your immune system is housed in the specialized tissue and gut microbes that populate your gastrointestinal (GI) tract. These little microbes have many functions that impact not only your immune system, but your overall health too. They send messages throughout your digestive system and help to shape the immune system. Just like the immune system, the digestive system is also complex and should be supported to keep things running correctly. Keeping our digestion healthy is the first step to a stronger immune system.
How Are They Connected?
The digestive system is a process that begins in the brain and continues from the mouth all the way through the GI tract. The GI tract is large and easily impacted by invaders including viruses, bacteria, and allergens from both food and the environment (like a flu virus or germs from unwashed hands). Your digestive system is equipped with physical barriers, like stomach acid and enzymes, whose main job is to stop pathogens before they can enter the intestines and disrupt your delicate microbial balance. If these initial physical barriers are not successful don’t fret, GI tract has a back-up plan!
If germs or allergens do make it past your stomach acid, there is a mucosal layer that acts as the first line of defense for the immune system and utilizes a combination of illness fighting organisms (like mucus and gut microbes) to prevent pathogens from continuing on. Those that are able to cross this barrier can trigger immune responses or increase overall inflammation throughout the body which may weaken your immune system.
The second line of defense is a tight layer of cells called the epithelium. These cells are rich in a microbe fighting enzyme called lysozyme which helps destroy pathogens and prevent them from crossing into the blood, decreasing your risk of an immune reaction.
Your digestive system is equipped with physical barriers, like stomach acid and enzymes, whose main job is to stop pathogens before they can enter the intestines and disrupt your delicate microbial balance.
Additionally, a healthy and diverse gut flora developed early in life helps to train the immune system to understand the difference between beneficial and pathogenic bacteria, stimulate an immune system response, crowd out pathogenic bacteria, and feed the cells. A high fiber diet, full of a variety of fruit, vegetables, and whole grains supports beneficial bacteria balance and the production of molecules such as short chain fatty acids (SCFAs) which feed the epithelial tissue. SCFAs boast many anti-inflammatory properties, boost antibody production, and support the strength of the digestive lining, all of which are essential for a well functioning immune system.
So What Could Go Wrong?
The digestive system is large with many different functions, so there is ample opportunity for things to go wrong and impact the immune system.
Starting with the upper GI system, inadequate stomach acid or enzyme production may interfere with digestion by only partially digesting food and allowing it to continue on before it is fully digested. When you’re not able to fully digest food it increases the risk of overgrowth of harmful microbes and potential adverse reactions to frequently consumed foods.
When undigested food particles move to the small intestine, they may damage the intestinal walls and increase your risk of “leaky gut.” Imagine bits of food banging and knocking into the walls of your intestine, creating little knicks and holes along the way. This can be magnified by other environmental factors including genetic predispositions, chronic stress, and exposure to toxins. Bits of food and microbes can then sneak through the intestinal wall and into the bloodstream. This can trigger an immune response as the body identifies these food particles as foreign invaders, and depletes immune stores in an attempt to fight them off.
When you’re not able to fully digest food it increases the risk of overgrowth of harmful microbes and potential adverse reactions to frequently consumed foods.
In the large intestine, microbes that have successfully made it this far can cause bacterial imbalances in the microbiome including an overgrowth of unhealthy bacteria, fungus, or parasites. The microbiome is an important physical barrier in the immune system and has many crucial roles including the protection against the invasion of potential pathogens, our “mucosal surveillance system,” and the manufacturing of important nutrients that help to keep you healthy.
Chronic stress, dietary imbalances, and certain medications can also affect microbial balance, digestive health, and weaken the immune system. `
The good news is that there’s a lot we can do to prevent things from going wrong and to heal digestion if we experience issues!
Support Digestion to Support the Immune System
A well functioning digestive system is essential for a strong immune system and in keeping you healthy! Remember, digestion is a process that starts in the brain, so support should start there and work its way down.
Be chill and get parasympathetic. We need to be in a calm, relaxed state in order to properly digest our foods. The parasympathetic nervous system is in charge of sending our body signals to slow down, breath, and relax. Engaging this system before eating is important to make sure that we set ourselves up for success to fully digest our food. Practicing deep breathing, getting outside, and imagery are all great ways that help to activate our relaxation system.
Support the production of digestive enzymes and stomach acid that help to break down food and stop potential pathogens. Consuming foods rich in zinc may help to stimulate and increase stomach acid production. Zinc rich foods include:
- Legumes: Chickpeas, lentils, black beans, kidney beans
- Nuts and seeds: Pumpkin seeds, cashews, hemp seeds
- Whole eggs
- Whole grains: Oats, quinoa, brown rice
- Some vegetables: Mushrooms, kale, peas, asparagus, and beet greens
Love on your liver and gallbladder. The liver and gallbladder are both important organs for the breakdown of food (especially fats), converting food into energy, and the elimination of waste. Utilizing digestive bitters prior to meals or consuming adequate amounts of magnesium-rich foods like almonds, and spinach can help support these organs in efficiently digesting and eliminating waste products.
Eat adequate fiber. A diet high in fiber and variety helps to support the gut’s microbiota balance, feed the beneficial bacteria, and provides the cells with the essential nutrients they need to produce protective enzymes like lysozyme. Fiber rich foods include:
- Whole grains
Supporting your digestion and immune system is essential for feeling great and functioning your best. Do you feel like you could use more targeted support? Check out our Digestive Maintenance essential curation, developed specifically with the health of your digestive system in mind.
Overwhelmed and confused about all of the contradicting nutrition and supplement advice out there? Our experienced Nutritional Therapy Practitioners will work with you to determine the right nutrition, lifestyle practices and supplements to support your personal health goals.
Emily Alexander, M.Ed, FNTP—Emily is a Nutritional Therapy Practitioner with Curated Wellness. She is passionate about supporting others in their journey to improve their relationship with food and their body through gentle nutrition, and is a firm believer that understanding the bio-individual components of nutrition is one of the best ways to do so. Emily completed her Master’s of education in health education and promotion with a concentration in eating disorders, and draws from both her educational background and life experience to help her clients improve their energy, understand their bodies, boost their athletic potential, and break down diet myths one at a time. Read more about Emily.
The information presented on this website is intended for educational purposes only. Statements within this site have not been evaluated or approved by the Food and Drug Administration. This content is not intended to diagnose, treat, cure, or prevent any specific condition or disease, nor is it medical advice and should not be considered a substitute for professional medical expertise. Readers of this content are advised to consult their doctors or qualified health professionals regarding specific health conditions or concerns. One should always consult a qualified medical professional before engaging in any dietary and/or lifestyle change or new health program. Curated Wellness does not take responsibility for any health consequences of any person or persons following the information in this educational content.
2. Kau, A. L., Ahern, P. P., Griffin, N. W., Goodman, A. L., & Gordon, J. I. (2011). Human nutrition, the gut microbiome and the immune system. Nature, 474(7351), 327–336. https://doi.org/10.1038/nature10213
3. Statovci, D., Aguilera, M., MacSharry, J., & Melgar, S. (2017). The Impact of Western Diet and Nutrients on the Microbiota and Immune Response at Mucosal Interfaces. Frontiers in immunology, 8, 838. https://doi.org/10.3389/fimmu.2017.00838