10 Things to Know About the Immune System

10 Things You Should Know About Your Immune System 



If we had a dollar for every time we’ve heard the word “immunity” this year, we could probably solve world hunger. Yet how much do any of us really know about our immune systems? For many of us, the last time we tried to understand biology was back in high school, and while we want to know more, who really has the time to figure out something too complicated for Twitter thread anyway?

We’re here to help! 

You don't need to become an expert in immune function overnight, but isn’t it always fun to throw down some hard facts at the dinner table? Don’t miss this chance to humble-brag about your burning scientific curiosity…


1.  The immune system is a complex network of tissues, cells and organs. Its soldiers find and destroy invaders--like viruses or harmful bacteria--to protect you from sickness and infection. These soldiers, white blood cells (WBC), are formed from stem cells. Because of this, the immune system recognizes only two things: self, and not-self.

2.  There are two types of immunity: Innate immunity is the body’s first line of defense against invaders. This system has its own ‘military branches’ made up of different WBC types. They identify and consume anything that is not-self [1].

3.  Innate immunity also includes the body’s external barriers, like our skin. Immune cells within our skin keep a lookout for any non-self invaders that may break through. It’s the body’s first, first line of defense [2].

4.  Then there’s adaptive immunity. These ‘special forces’ are called in when the innate immune system needs assistance. In an adaptive immune response, your immune cells produce antibodies that latch onto and neutralize invaders, making them easier to kill [1].

5.  You build immunity over time. Antibodies are specific to the pathogens they attack, and when the job is done, some stick around. This allows your immune system to handle familiar invaders more quickly (often before you feel ill). Over time, your body develops a “library” of familiar antibodies. And that’s how you build immunity.



Now that you’re familiar with the basics, here are a few more things you might want to know: 

6.  We're not born with fully developed immune systems. While we do have innate immunity at birth, our more powerful defense--adaptive immunity--is completely dependent upon borrowed immunity from our mothers. She shares her antibodies in the womb and through breast feeding. It is not until somewhere between ages 5 and 7 that our immune systems are fully developed [3], [4].

7.  Probiotics--what’s the big deal? We’ll tell you! A diverse gut microbiome is essential to proper immune function. Why? Because the trillions of microbes living in your gut actually teach your immune cells the difference between “self” and “not-self.” Plus, once developed, your gut microbiota also modulate immune activity [5].

8.  Immune cells rely on adequate nutrition, so eating a diet rich in vitamins and micronutrients will ensure proper immune function. Meat, eggs, nuts and seeds will provide vitamin A (for skin and gut health), B vitamins and micronutrients (for proper immune cell formation). Consuming a variety of grains, beans and vegetables will round out your nutrient intake with vitamins essential for reducing inflammation [6].

9.  Laughter improves immunity! Stress releases hormones like cortisol that suppress the immune system, decreasing the amount of Natural Killer Cells (which fight against viruses and cancer). On the other hand, laughter has been proven to reduce cortisol and increase the number of Natural Killer Cells [7].

10.  Sleep plays a large role in immune system regulation. When we’re sick we sleep so the immune system can become more active to fight infection. When we’re healthy, we sleep so the immune system can become just active enough to help us recover from the day. Those who have long-term sleep deficiencies generally suffer from low-grade inflammation. Since sleep cycles generally last 90 minutes, aiming for 7.5 to 9 hours of sleep each night will help to reduce inflammation and regulate immune function [8].


The most important thing to remember is that your immune system is incredibly complex and relies on many different systems in your body to function properly. That's why it's essential to make sure that you're getting all the vitamins and nutrients that your body needs on a regular basis. Plus, work on healthy habits like managing stress, getting enough sleep and staying active. 

Need some inspiration? Check out our 28-Day February Reset program for 4-weeks worth of easy ideas for supporting total health through your daily routine. 



Excited about Immunity? Looking to learn more? Here are some of our team’s favorite resources:

Fun Facts from Healthline

This intro from Medical News Today

An article from the Cleveland Clinic

This overview by the NIH



[1] Institute for Quality and Efficiency in Health Care, “The innate and adaptive immune systems. InformedHealth.org,” Jul. 30, 2020. https://www.ncbi.nlm.nih.gov/books/NBK279396/ (accessed Sep. 26, 2020).

[2] A. V. Nguyen and A. M. Soulika, “The Dynamics of the Skin’s Immune System,” IJMS, vol. 20, no. 8, p. 1811, Apr. 2019, doi: 10.3390/ijms20081811.

[3] A. K. Simon, G. A. Hollander, and A. McMichael, “Evolution of the immune system in humans from infancy to old age,” Proc. R. Soc. B., vol. 282, no. 1821, p. 20143085, Dec. 2015, doi: 10.1098/rspb.2014.3085.

[4] D. L. Hill et al., “Immune system development varies according to age, location, and anemia in African children,” Sci. Transl. Med., vol. 12, no. 529, p. eaaw9522, Feb. 2020, doi: 10.1126/scitranslmed.aaw9522.

[5] V. Lazar et al., “Aspects of Gut Microbiota and Immune System Interactions in Infectious Diseases, Immunopathology, and Cancer,” Front. Immunol., vol. 9, p. 1830, Aug. 2018, doi: 10.3389/fimmu.2018.01830.

[6] A. F. Gombart, A. Pierre, and S. Maggini, “A Review of Micronutrients and the Immune System–Working in Harmony to Reduce the Risk of Infection,” Nutrients, vol. 12, no. 1, p. 236, Jan. 2020, doi: 10.3390/nu12010236.

[7] M. P. Bennett, J. M. Zeller, L. Rosenberg, and J. McCann, “The Effect of Mirthful Laughter on Stress and Natural Killer Cell Activity,” p. 9.

[8] L. Besedovsky, T. Lange, and M. Haack, “The Sleep-Immune Crosstalk in Health and Disease,” Physiological Reviews, vol. 99, no. 3, pp. 1325–1380, Jul. 2019, doi: 10.1152/physrev.00010.2018.