The health of your gastrointestinal tract is directly related to the health and function of your immune system. The microbiome is a collection of microorganisms that are predominantly found in your gut. For example, your gut bacteria have many beneficial roles such as regulating your metabolism, mood, cognitive function, appetite, digestion and immunity.1 Just as the majority of the microbiome lives in the gut, so does about 70% of your immune system.1 The gut is a great place for the majority of the immune system to be located since this is where many harmful pathogens including viruses, parasites and harmful bacteria first enter your body.
A Symbiotic Relationship
The immune system and gut therefore have a symbiotic relationship. This means that both the immune system of the human and the microbiome benefit from this connection. The good bacteria that are part of the microbiome train the immune cells to distinguish between ‘non-self’ and ‘self’ while the gut signals the immune system to generate the appropriate immune responses2. The immune system on the other hand, helps to maintain a healthy microbiome with plenty of diversity.2 This delicate two-way communication between your gut and immune cells can be supported through the right lifestyle choices and specific nutrients.
Nutrition and Probiotics
When you eat a diet rich in probiotic foods such as kefir and sauerkraut, prebiotic fibre (found in vegetables and legumes) and decrease inflammatory processed foods (granola bars, frozen dinners, store bought baked goods) these dietary shifts can increase the resilience of the gut microbiome and therefore the strength of your immune system.3 In one study, individuals infected with the common cold were separated into two groups; one group received a probiotic supplement and the other received a placebo. The group that received the probiotic had a stronger immune response and decreased viral shedding (via nasal or oral secretions). 4 So, during cold and flu season, it may be beneficial to add a probiotic supplement to decrease the likelihood of infection and transmission.
Multivitamin, Vitamin C & D
Most people do not consume enough fruits and vegetables5 and this can lead to a lack of nutrients. Therefore, adding in a high-quality multivitamin can help maintain proper immune function by providing the key nutrients utilized by your immune system. A multivitamin can help to fill gaps in your nutritional intake as needed. Furthermore, vitamins C and D can be helpful to take in addition to a multivitamin. Vitamin D deficiency is associated with poor immune function and gut dysbiosis (an imbalance between the beneficial and harmful bacteria in the gut).6 The lack of sun exposure during the winter months puts many people living in northern latitudes at risk of sub optimal vitamin D levels. People with olive and dark skin tones are at an even greater risk as melanin will reduce vitamin D synthesis in your skin. A vitamin D supplement can help. However, consider testing your levels with your health care provider to determine exactly how much you should be taking. Vitamin C is also an essential nutrient for our immune system, especially because our body can not make it and has to come either from our diet or from a supplement.8 Vitamin C is important for our immune system as it helps increase the activity of important immune cells and helps with antibody production.8
Echinacea, Zinc & Medicinal Mushrooms
When you are feeling run-down or if you are at the early onset of an upper respiratory tract infection, additional supplementation with echinacea, zinc or medicinal mushrooms can support a helpful immune response. Echinacea has been used traditionally in herbal medicine to shorten the duration of cold and flu symptoms.9 Zinc is a mineral which is needed for proper immune function & is crucial for the development and function of immune cells.10 Supplementing with zinc was found to reduce the duration of the common cold by 33% in a 2017 study.11 Mushrooms can be helpful in the immune response in part, due to their beta-glucan content. Beta-glucans are special polysaccharides found in the cell walls of mushrooms and yeasts such as Saccharomyces cerevisiae. Glucans are part of a group of biologically active natural molecules with immune-stimulating function.12
Your gut and immune system are deeply connected. The health of one system is dependent on the other. Therefore, it is crucial to maintain the health of your gut microbiome by eating a wide range of nutritious foods and by considering the appropriate immune and gut supporting supplements.
- Cohen, Sandy. UCLA health. If you want to boost immunity, look to the gut. March 19, 2021. https://connect.uclahealth.org/2021/03/19/want-to-boost-immunity-look-to-the-gut/#:~:text=70%25%20of%20the%20immune%20system,diet%20affects%20the%20immune%20system.
- Zheng D, Liwinski T, Elinav E. Interaction between microbiota and immunity in health and disease. Cell research. 2020 Jun;30(6):492-506.
- Wiertsema SP, van Bergenhenegouwen J, Garssen J, Knippels LMJ. The Interplay between the Gut Microbiome and the Immune System in the Context of Infectious Diseases throughout Life and the Role of Nutrition in Optimizing Treatment Strategies. Nutrients. 2021 Mar 9;13(3):886. doi: 10.3390/nu13030886. PMID: 33803407; PMCID: PMC8001875.
- Turner RB, Woodfolk JA, Borish L, Steinke JW, Patrie JT, Muehling LM, Lahtinen S, Lehtinen MJ. Effect of probiotic on innate inflammatory response and viral shedding in experimental rhinovirus infection–a randomised controlled trial. Beneficial microbes. 2017 Apr 26;8(2):207.
- Centers for Disease Control and Prevention. (2017, November 16). Only 1 in 10 adults get enough fruits or vegetables. Centers for Disease Control and Prevention. Retrieved January 26, 2022, from https://www.cdc.gov/media/releases/2017/p1116-fruit-vegetable-consumption.html
- Tabatabaeizadeh SA, Tafazoli N, Ferns GA, Avan A, Ghayour-Mobarhan M. Vitamin D, the gut microbiome and inflammatory bowel disease. Journal of research in medical sciences: the official journal of Isfahan University of Medical Sciences. 2018;23.
- Janz T, Pearson C. Vitamin D blood levels of Canadians. Statistics Canada Catalogue no. 82624-x. Accessed Nov 1, 2020 at: https://www150.statcan.gc.ca/n1/pub/82-624-x/2013001/article/11727-eng.htm
- Bucher, A., & White, N. (2016). Vitamin C in the Prevention and Treatment of the Common Cold. American journal of lifestyle medicine, 10(3), 181–183. https://doi.org/10.1177/1559827616629092
- Karsch-Völk, M., Barrett, B., & Linde, K. (2015). Echinacea for preventing and treating the common cold. JAMA, 313(6), 618. https://doi.org/10.1001/jama.2014.17145
- Science, M., Johnstone, J., Roth, D. E., Guyatt, G., & Loeb, M. (2012). Zinc for the treatment of the common cold: A systematic review and meta-analysis of randomized controlled trials. Canadian Medical Association Journal, 184(10). https://doi.org/10.1503/cmaj.111990
- Hemilä H. Zinc lozenges and the common cold: a meta-analysis comparing zinc acetate and zinc gluconate, and the role of zinc dosage. JRSM open. 2017 Apr;8(5):2054270417694291.
- kramienė D, Kondrotas A, Didžiapetrienė J, Kėvelaitis E. Effects of ß-glucans on the immune system. Medicina. 2007 Aug;43(8):597.