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Shielding our Health

The immune system is a complex network of cells, tissues, and organs that work together to protect us from harmful invaders, such as bacteria, viruses, parasites, and toxins. This protection allows us to maintain our health. However, in order to stay healthy, it’s important to take good care of this system.

So, what can we do to support our immune system to function optimally? There are many things to consider when talking about protecting our immune system. But, some of the most important things are following a healthy diet[1]; adopting good sleep hygiene[2]; performing regular exercise [3],[4]; and being particularly careful with proper stress management[5].

Immune System


The field of science that studies the immune system and its functions is called immunology. And it helps us understand how the immune system recognizes and eliminates invaders[1]. Not only that, but our immune systems can also adapt and remember previous encounters with invaders. It has a memory[2]. Thus, immunology also helps us understand how the immune system can malfunction or become imbalanced; leading to allergies, autoimmune diseases, immunodeficiency, or immune exhaustion[3]. So, the question you might be asking is: how does it work?

As we have already discussed in previous blog posts, the immune system is based on three main players: antibodies, antigens[4], and cytokines[5].

Antibodies are specialized proteins produced by B-lymphocytes that can recognize specific molecules (antigens); which are unique to particular threats (such as foreign substances or pathogens like bacteria). Once the immune system detects an invader, it will produce special small molecule messengers called cytokines. These molecules will then enter the bloodstream and spread the news about the invasion (not only to relocate other resources from the immune systems, but also to alert the nervous and endocrine systems that a fight is about to happen).

As you can imagine, as long as the messengers are circulating, the immune system will be active in its fight. This is why we can think of cytokines as regulators of the duration and intensity of the immune response[1].

This entire sequence of events, from recognizing the invader up to its annihilation and restoration of balance (homeostasis), is what we commonly call inflammation[2].

The Pros and Cons of Inflammation in our Immune Health

Inflammation is an important and essential physiological mechanism that helps us stay shielded from the things that can make us sick. However, we keep hearing things like “inflammation is causing disease” and that we “need to lower inflammation”. What should we believe? Is inflammation a good thing or a bad thing?

Let’s understand what it is so we can come to a conclusion.

Inflammation is the process by which the body increases blood flow and sends immune cells and other mediator agents to the site of injury or infection. This is why we feel the warmth and see redness in a wound[1]. However, chronic inflammation can be troublesome. In this scenario, we have a non-stop battle that usually results in several casualties and even some friendly fire. Chronic inflammation  can contribute to various diseases, such as diabetes, cardiovascular disease, arthritis, and cancer[2].

This overactivation of our immune system, and of the inflammatory response, will compromise our body’s ability to achieve homeostasis; ultimately leading to the inability to repair and heal[3].

Overactive and Underactive Immune Systems: Health Implications

On the one hand, an overactive immune system is one that reacts excessively or inappropriately to substances or situations that are normally harmless. On the other hand, an underactive immune system is one that fails to respond adequately or effectively to pathogens or toxins; which results in increased susceptibility to infections and diseases.

Let us clarify these differences with some examples.

An overactive immune system reaction can be split into two big groups: allergic reactions (e.g. allergic asthma and eczema) and autoimmune diseases (e.g. rheumatoid arthritis or multiple sclerosis). The first are caused by “external” allergens, such as dust, food, animal dander, or pollen. The second occurs when our immune system mistakenly considers our own cells as a threat and attacks our tissues and organs[1].

Now, what happens when there are no attacks when the immune system is underactive?

Well, an underactive immune system is one that fails to respond adequately; and this increases the susceptibility to infections and diseases[1]. But what causes it? Similar to an overactive immune system, it can be due to genetic factors, primary and secondary immunodeficiency disorders, cancer, malnutrition, aging, or certain medications.[2],[3] [4],[5] The consequences of an underactive immune system are frequent or severe infections, slow wound healing, fatigue, weight loss, or organ failure.

As you can see, there are different causes for an unbalanced immune system. Probably the most important question here is… Why are we now experiencing all of these issues with our immune systems?

Some say that we are suffering from immune exhaustion and that our bodies can no longer respond to invaders[6]. If that is true, what is causing this exhaustion? What has changed in order to cause our immune response to burnout?

Well, since most pathogens have not changed over time, we have to shift our attention to the chemicals and pollutants around us (introduced with the industrial revolution[7]); and the new forms of chronic stress in our lives[8].

Since in previous articles we already went over our chemical exposure, in this article we will focus on stress.


There is a field of study that looks at the interactions between the central nervous system and the immune system; it is called psychoneuroimmunology (PNI)[1].

One of the things that PNI researchers have been looking at lately is the effect of stress on our mucosal barriers (the layers of cells in our gut and respiratory system that keep the harmful stuff out). Well, stress can wreak havoc on those barriers; compromising their integrity and causing all sorts of health problems.

Let’s start with the gut. When we’re stressed, our bodies release a hormone called cortisol. And while cortisol can be helpful in the short term (it’s part of our “fight or flight” response), over time it can damage the tight junctions between cells in the gut’s mucosal barrier.[2] This can lead to a condition called leaky gut (or intestinal permeability) where harmful substances are able to pass through into the bloodstream. And trust us, you do not want a leaky gut. It’s been linked to all sorts of issues, from autoimmune disorders to depression (learn more here).

Now, let’s move on to the respiratory system. When we’re stressed, our immune system can become compromised; making it easier for bacteria and viruses to penetrate the mucosal barrier in our lungs. That’s right, stress can literally make us more susceptible to respiratory infections.[1]  Ain’t that just lovely?

Last but not least, let’s talk about the brain-blood barrier. While this is not a mucosal barrier, it also keeps harmful substances out of our brains. When we’re stressed, cortisol can increase the permeability of the blood-brain barrier, allowing all sorts of nasty stuff to get in there and wreak havoc. This can lead to depression, anxiety, and cognitive decline.[2]

So, what’s the takeaway here? Well, for starters, it’s clear that stress is no joke. It can have serious, long-term effects on our health. But the good news is that there are ways to manage stress and keep our mucosal barriers intact. Things like meditation, exercise, and a healthy diet can all help keep our bodies in tip-top shape. So take a deep breath, relax, and remember that your body and mind are worth taking care of.


In conclusion, our immune system is crucial for us to have thriving lives. If we want to be healthier and live longer, it is our responsibility to act in the best way possible to provide our body with what it needs to function optimally. As evidenced in this post, stress plays an important role in our health. Remember that our mind and our body are connected. So, by regulating our emotions, we will also be taking care of our beloved immune system.

If you enjoyed this article, you will absolutely love Dr. De’s webinar with Dr. Engelman. In this eye-opening interview, they share some surprising information about the immune system and human health.

As always, if you have questions about how you can start optimizing your immune system and your healthspan, get in touch with us.

Just click the button below, and one of our team members will contact you.

[1] https://pubmed.ncbi.nlm.nih.gov/31426423/
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3256323/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8531728/
[4] https://www.sciencedirect.com/science/article/pii/B9780128145937000153
[5] https://pubmed.ncbi.nlm.nih.gov/19236337/
[1] https://www.immunology.org/public-information/what-immunology
[2] https://www.ncbi.nlm.nih.gov/books/NBK27158/
[3] https://journals.plos.org/plospathogens/article?id=10.1371/journal.ppat.1009892
[4] https://www.niaid.nih.gov/research/immune-response-features
[5] https://pubmed.ncbi.nlm.nih.gov/8813336/
[1] https://onlinelibrary.wiley.com/doi/full/10.1002/advs.202004433
[2] https://www.niehs.nih.gov/health/topics/conditions/inflammation/index.cfm
[1] https://www.niehs.nih.gov/health/topics/conditions/inflammation/index.cfm
[2] https://www.ncbi.nlm.nih.gov/books/NBK493173/
[3] https://www.nature.com/articles/s41467-018-05800-6
[1] https://www.niehs.nih.gov/health/topics/conditions/autoimmune/index.cfm
[1] https://pubmed.ncbi.nlm.nih.gov/11403834/
[2] https://www.ncbi.nlm.nih.gov/books/NBK500027/
[3] https://pubmed.ncbi.nlm.nih.gov/26454309/
[4] https://www.frontiersin.org/articles/10.3389/fimmu.2022.928062/full
[5] https://www.cdc.gov/genomics/disease/primary_immunodeficiency.htm
[6] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842494/
[7] https://hal.science/hal-01010157/document
[8] https://link.springer.com/chapter/10.1007/978-981-10-0875-7_22
[1] https://pubmed.ncbi.nlm.nih.gov/9401604/
[2] https://www.nature.com/articles/s41598-017-04755-w
[1] https://pubmed.ncbi.nlm.nih.gov/33338918/
[2] https://www.sciencedirect.com/science/article/pii/S0009898113001484


Marcos de Andrade MD, MBA
Chief Executive Officer