Whenever an infectious disease threatens the health of many, the topic of how our immune system operates often arises. Across the board, the human immune response helps to manage a plethora of tasks, the most important of which is fighting pathogens. Properly employing it in times of sickness is an important part of keeping us well. Since a large proportion of our immune system is housed within our gut, the gut microbiome plays a pivotal role in determining when and how well our immune response operates.
Keeping our immune system functioning optimally is on many people’s minds right now, especially with the prevalence of respiratory illness and as viral infections continue to impact our communities. With increasing concerns about seasonal infectious diseases like influenza, and recently novel coronavirus (aka COVID 19) many people are looking to see if there are ways they can improve their ongoing immunity. While there are specific measures those at risk of or experiencing symptoms should take (https://www.cdc.gov/coronavirus/2019-ncov/summary.html) the latest science shows there can be an ongoing beneficial relationship between your gut microbiome, the foods that you eat, and overall immunity. Let us use this current period to educate ourselves on ways to better our immune systems and understand the many ways we can take control over our health.
We Live in a World of Microorganisms
As we watch many cleaning agents fly off the shelves in our local stores, it’s normal to imagine the benefits of a sterile environment in fighting infections or preventing disease, but our bodies are far from a microbe-free environment. Rather, the reality is our bodies are full of caverns rich in microscopic organisms that help us maintain internal homeostasis and immunostasis – often by interacting with our immune cells. These “conversations” have been shown to affect autoimmunity, inflammation, cancer, and our susceptibility to infection.
The gut microbiome aids in orchestrating these communications. Depending on the balance and fitness of the gut flora, our immune response can prove to be strong and resilient, or weak and late to the game. Nurturing our gut ecosystem can be one of the most profound ways we can beef up our immune response. Fortunately, there is a natural role between our diet and the composition of our gut microbiome, making manipulating and adjusting our gut flora within grasp. Viome's mission is to put people in control of their health and ultimately prevent and reverse chronic disease. The best way we can manage this is together by learning how to use nutrition as a means of preventative medicine – for both chronic disease and infectious agents – and by each person taking the necessary steps to get their health on track. However, this isn’t a one-size-fits-all path. Each individual requires unique guidance that can depend upon age, gender, health, genetics, geographical location, and environmental factors (to name a few). But although your Viome food and supplement recommendations may vary from you to your neighbor, the goals often remain the same: getting your gut lining to optimal health and balancing your own unique gut microbiome.
From the Inside-Out
It’s not always about the microbes, directly. Think of your gut microbiome as a tool that can simultaneously tell you how efficient of a job it’s doing. When dysfunctional, it can cause unintentional harm when performing its normal tasks, like a dull knife. However, when kept in fit condition, it performs seamlessly and precisely with less risk to surrounding areas. In this manner, a healthy gut microbiome functions well and is less likely to harm your intestinal lining. This thin barrier keeps the microbes safe and sound in their preferred environment - your gut - and keeps them from exploring other areas we don’t want – like in your blood.
When the intestinal lining is compromised, our gut microbes can escape and wind up in places they don’t belong, like other organs. As they accrue in these areas, the toxins and metabolites they secrete can lead to inflammatory reactions that damage these tissues and lead to the development of chronic conditions. This is one of the many reasons why we believe so strongly in re-establishing a healthy gut lining. But it also plays a role in managing our immune response in times of infection.
Out-Maneuvering Pathogenic Bacteria
Many commensal - or beneficial - microbes help to maintain the health of the gut lining. This can be from metabolizing fiber to produce butyrate, a healthy food for our gut lining cells, to competing with pathogens for space. When our gut microbiome has a healthy butyrate production, it helps our intestinal lining stay strong and remain intact. Conversely, our gut lining returns the favor by protecting many of these commensal bacteria communities when pathogens are sensed. In fact, our immune cells can be so “smart” that they recognize special peptides on the outside of beneficial bacteria that signal to the immune cells they’re safe and not foreign at all. Convenient, isn’t it?
This is just one of many ways our friendly gut microbes help us fight pathogens. Additionally, when their populations are strong, they also out-compete for space! Many pathogens prefer special sites of attachment on our gut lining cells. With a healthy, diverse microbiome – these sites are taken up, leaving pathogens with few places to settle.
They Help Fight Viruses, Too
When it comes to viruses, bacteria are much like us. They, too, are susceptible to viral infections and employ unique ways to keep them and their environment healthy. When the populations of beneficial microbes are balanced and strong, it can be easier for them to communicate among each other when they sense a new viral pathogen. This communication, called quorum sensing, helps them react faster to their own immune defense. Once they respond they retain “memories” of their viral defense mechanisms in their genetic code, passing on their immunity to future generations. This translates to healthy commensal populations that are less likely to be wiped out from viruses, impacting the health of our gut.
Surprisingly, our gut microbes might even affect viruses that impact us.
Some viruses, such as the influenza virus, enter our lungs and require rapid antibody responses from our immune system. The faster the recognition of the virus, the faster our immune system can work to remove the infection. For immune cells patrolling the lungs, quick identification of the viral pathogen means a better outcome. Several studies have documented that our gut microbiome helps support “adaptive immunity” or our specialized immune response that fights disease by producing antibodies. Our “adaptive” immune cells carry a variety of “keys” – each key matching with a different virus’s “keyhole”. Scientists believe that some of our gut microbes might actually be the ones providing the “keys” to our immune cells. For example, it could be that some of the byproducts these bacteria produce are converted into the keys they need to recognize viruses. In the case of the influenza, scientists found that this exchange between the gut microbes and our immune system resulted in faster recognition of the influenza virus from immune cells inside the lungs.
And this is just the beginning.
This field of research is expanding each day, with new discoveries constantly shedding light on the interconnectedness of our immune system with our gut flora. And to imagine – we can and do constantly change our gut ecosystem based on the foods we eat. That means directly influencing how our immune system responds simply based on what foods we find out are right for our gut microbiome right now.
The answer to optimal health isn’t necessarily reaching for the hand-sanitizer whenever you hear someone cough – it really starts with how you’re treating yourself each day. If you’re focused on making the right decisions for you and eating a variety of healthy foods to optimize your gut microbiome, you’re bettering your odds at a strong immune response to stop infections in their tracks. Take the time to build your internal gut ecosystem. Just like your stock portfolio – balance and diversify your gut microbiome, starting with the personalized recommendations we send straight to your Viome App.
Links to recent articles and published papers connecting the microbiome and immunity:
Interactions Between the Microbiota and the Immune System (Science, June 2018)
The microbiome and innate immunity (Nature 06 July 2016)
The microbial metabolite desaminotyrosine protects from influenza through type I interferon (Science, 4 August 2017)
Connecting the Gut Microbiome with Response to Infectious Respiratory Disease in Humans and Pigs (Kansas State University One Health Newsletter: Volume 10 Issue 2)
"The gut microbiota plays a protective role in the host defence against pneumococcal pneumonia" (BMJ Gut Oct 2018)
"Microbiota regulates immune defense against respiratory tract influenza A virus infection" (PNAS March 2011)
Demystifying the manipulation of host immunity, metabolism, and extraintestinal tumors by the gut microbiome (Nature 12 October 2019)
The Gut: Where Bacteria and Immune System Meet (John Hopkins Medicine November 2015)