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5 Goals to Strengthen Your Immune System

Without a healthy immune system, it is difficult for your body to fight off viral and bacterial infections. Luckily, there are many things that you can do to help your immune system function at optimal levels. To help you understand how your immune system works, and what steps you can take to support it, we have been posting a series of articles. In the first article, we discussed the 5 Pillars of Health, and the actions you can take to keep each pillar strong. In the second article, we provided a very basic overview of how your immune system works, to give you a basis of understanding for the rest of the series. In this article, we are going to discuss the five goals we target to strengthen the immune system.

5 Goals to Strengthen Your Immune System

Goal One


Enhance barrier integrity: improve the lining of our respiratory tract, gut, blood-brain barrier, and skin.

Skin makes up a majority of the barrier. It creates a physical barrier and is also home to a host of microorganisms that protect your body from viruses and bacteria (1). Specific cells that live in the skin create antimicrobial peptides, which not only kill microbes, but also form a chemical shield over the skin.

The lining of your respiratory tract and digestive tract are another large part of the barrier defense. Parts are lined with cells that help sweep foreign substances away and produce mucus that traps germs so they can be destroyed and removed. Mucus also contains immune cells, antimicrobial peptides, and healthy microbes that works to protect your body from pathogens.

  • You can enhance the physical barrier by cleaning your hands and face regularly. In doing so you will wash away many of the germs that sit on your skin. As you may already know, a quick rinse will not do the trick. Be sure to wash well, for at least 20 seconds. If your hands become dry from frequent washing, it is important to use a moisturizer. Dry skin can crack and allow germs to enter through the cracks.

  • You can protect your respiratory barriers by keeping your distance. The closer you are to people as they cough, sneeze, speak, or even breathe, the greater exposure you will have to their germs. When you are exposed to just a few pathogens, your immune system can fight them off pretty easily. However, when greater numbers enter your body, your chances of becoming ill are increased.

  • While many people remember this as they are in public, it is also important to remember it at home. If someone in your home is ill, be sure to wash your hands frequently and try to keep your space to reduce the number of germs that enter your body.

  • Since the skin and the linings of your respiratory tract and digestive system make up such a large part of your body, if they are not cared for it can negatively impact your health. Environmental toxins that are consumed, breathed, or that come into contact with your skin, can cause much more harm than you realize. It is important to protect this vital barrier defense from environmental toxins.

  • Many nutrients can support and improve the barrier defense. Vitamin D and Vitamin C are two examples of nutrients that are vital to the health of your skin and immune function within the skin (2, 3).

Goal Two


Increase production of antimicrobial peptides: small amino acid linked chains that fight against infections.

Antimicrobial peptides (AMPs) are found in secretions covering the skin and mucosal surfaces and in neutrophils (a type of white blood cell). Most AMPs work as potent antibiotics, neutralize pathogenic toxins, contribute to the chemical skin barrier, and regulate the immune response which includes modulating inflammation (4, 5). They “are also thought to trigger and coordinate multiple components of the innate and adaptive immune system” (6). As you can see, AMPs are vital in the function of your immune system

  • Sufficient levels of Vitamin D3 are necessary to induce certain AMPs (7, 8). Peptides in fermented foods also increase your own antimicrobial peptides (9).

Goal Three


Promote phagocytosis: a process when white blood cells, such as macrophages, are better able to recognize and consume infected cells, microbes and/or viral capsids.

Phagocytosis occurs once a pathogen has breached the barrier defenses. Specific white blood cells consume the virus, bacteria, and even our own infected or dying cells. They prevent infection and clean up damaged or dying cells in an area.

There are a few main types of white blood cells that are classified as phagocytes. One type, macrophages, also initiate the adaptive immune response, induce inflammation, and recruit other immune cells. Neutrophils are another type, which kill pathogens using AMPs, enzymes, and reactive oxygen species. Neutrophils also induce inflammation and release cytokines.

Without sufficient levels of phagocytes, you are more prone to severe infections. If your levels of white blood cells are consistently low, then you are considered to be immunocompromised. As COVID-19 has made abundantly clear, you do not want to be immunocompromised when you are exposed to a virus.

  • Many different foods and supplements stimulate phagocytosis in a variety of ways. Here are just a few examples. Lean proteins provide the building blocks for your body to create new white blood cells. Vitamin B12 and folate are also necessary to produce white blood cells (10). Echinacea and certain probiotics stimulate phagocytosis and production of phagocytes (11, 12, 13).

Goal Four


Decrease inflammation and restore redox balance: lots of oxygen free radicals lead to immune imbalance and increased inflammatory products.

As mentioned above, white blood cells induce inflammation and produce reactive oxygen species (free radicals) to kill pathogens. As important as phagocytosis, reactive oxygen species, and inflammation are in immune function, it is equally important that your body be able to regulate these responses. If left unchecked, they can create widespread tissue damage, severe illness, and even death.

Strengthen Your Immune System

When you have too many free radicals in your body, it can lead to many different diseases and inflammatory conditions. Your body needs to maintain a proper balance between free radicals and antioxidants.

  • Your lifestyle choices regarding sleep, exercise, nutrition, and stress management play a role in inflammation and redox balance. Sleep is vitally important in controlling inflammation (14). Vit C reduces toxic oxidants (3). Antioxidant rich foods do the same.. While echinacea stimulates phagocytosis, it also modulates the immune response and creates anti-inflammatory activity (15, 16).

Goal Five


Activate intracellular defense pathways: a process that allows cells that take on pathogens to kill them before they can replicate or cause damage (Nrf2 and SIRT1 activation.)

Nrf2 and SIRT1 are proteins that influence many different processes in our body. One important function shared by both is the activation of certain aspects of the immune system to defend against pathogens.

Many viruses cause Nrf2 activation, but some inhibit its activation (17). In addition to activating intracellular defense pathways, Nrf2 also protects against dysregulated inflammation (18).

SIRT1 controls the production of pro-inflammatory cytokines, is important in phagocytosis and antigen processing and presentation, and plays a crucial role in the activation and function of T-cells (19).

  • Luckily, many different fruits, vegetables and spices such as turmeric, grapes, onions, tomatoes, and green tea contain substances that activate Nrf2 and SIRT1. A diet rich in fruits, vegetables, and probiotics such as Lactobacillus plantarumLactobacillus brevis, and Lactobacillus collinoides found in fermented foods will support this goal (20, 21).

In this article, we gave a few examples of nutrients that are important to support each goal. In future articles, we will discuss the specific supplements that we recommend to our patients to support the immune system. We will also provide scientific evidence that shows how each supplement supports the five goals to strengthen your immune system and the five pillars of health.

If you want to gain more information and begin supporting your immune system, we are available to help. Please contact us to set up a telemedicine appointment. We would be privileged to help you determine the best regimen for your specific needs and support you in any lifestyle or dietary changes that you choose to implement.


Jonathan Vellinga, M.D.

Jonathan Vellinga, M.D. is an Internal Medicine practitioner with a broad interest in medicine. He graduated Summa cum laude from Weber State University in Clinical Laboratory Sciences and completed his medical degree from the Medical College of Wisconsin.​

Upon graduation from medical school, he completed his Internal Medicine residency at the University of Michigan. Dr. Vellinga is board-certified with the American Board of Internal Medicine and a member of the Institute for Functional Medicine.



1. Grice, Elizabeth A, and Julia A Segre. “The skin microbiome.” Nature reviews. Microbiology vol. 9,4 (2011): 244-53. doi:10.1038/nrmicro2537

2. Mostafa, Wedad Z, and Rehab A Hegazy. “Vitamin D and the skin: Focus on a complex relationship: A review.” Journal of advanced research vol. 6,6 (2015): 793-804. doi:10.1016/j.jare.2014.01.011

3. Pullar, Juliet M et al. “The Roles of Vitamin C in Skin Health.” Nutrients vol. 9,8 866. 12 Aug. 2017, doi:10.3390/nu9080866

4. Wang G. Human antimicrobial peptides and proteins. Pharmaceuticals (Basel). 2014;7(5):545–594. Published 2014 May 13. doi:10.3390/ph7050545

5. Wiesner, Jochen, and Andreas Vilcinskas. “Antimicrobial peptides: the ancient arm of the human immune system.” Virulence vol. 1,5 (2010): 440-64. doi:10.4161/viru.1.5.12983

6. Schauber, Jürgen, and Richard L Gallo. “Antimicrobial peptides and the skin immune defense system.” The Journal of allergy and clinical immunology vol. 122,2 (2008): 261-6. doi:10.1016/j.jaci.2008.03.027

7. Weber G, Heilborn JD, Chamorro Jimenez CI, Hammarsjo A, Törmä H, Stahle M. Vitamin D induces the antimicrobial protein hCAP18 in human skin. J Invest Dermatol. 2005;124(5):1080–1082. doi:10.1111/j.0022-202X.2005.23687.x

8. Liu PT, Stenger S, Li H, et al. Toll-like receptor triggering of a vitamin D-mediated human antimicrobial response. Science. 2006;311(5768):1770–1773. doi:10.1126/science.1123933

9. Shirako, S., Kojima, Y., Tomari, N. et al. Pyroglutamyl leucine, a peptide in fermented foods, attenuates dysbiosis by increasing host antimicrobial peptide. npj Sci Food 3, 18 (2019).

10. Koiso H, Tsukamoto N, Shimano S, Karasawa M, Murakami H, Nojima Y. Chronic myelogenous leukemia accompanied by megaloblastic anemia showing atypical clinical features. Rinsho Ketsueki. 2011;52(11):1772–1776.

11. Stimpel, M et al. “Macrophage activation and induction of macrophage cytotoxicity by purified polysaccharide fractions from the plant Echinacea purpurea.” Infection and immunity vol. 46,3 (1984): 845-9.

12. Gill, H S et al. “Enhancement of immunity in the elderly by dietary supplementation with the probiotic Bifidobacterium lactis HN019.” The American journal of clinical nutrition vol. 74,6 (2001): 833-9. doi:10.1093/ajcn/74.6.833

13. Gill, Harsharnjit & Rutherfurd-Markwick, Kay. (2001). Probiotic supplementation to enhance natural immunity in the elderly: effects of a newly characterized immunostimulatory strain Lactobacillus rhamnosus HN001 (DR20 (TM)) on leucocyte phagocytosis. Nutrition Research - NUTR RES. 21. 183-189. 10.1016/S0271-5317(00)00294-3.

14. Besedovsky, L., Lange, T., & Born, J. (2012). Sleep and immune function. Pflugers Archiv: European journal of physiology463(1), 121–137.

15. Sharma M, Schoop R, Hudson JB. Echinacea as an antiinflammatory agent: the influence of physiologically relevant parameters. Phytother Res. 2009;23(6):863–867. doi:10.1002/ptr.2714

16. Zhai, Zili et al. “Enhancement of innate and adaptive immune functions by multiple Echinacea species.” Journal of medicinal food vol. 10,3 (2007): 423-34. doi:10.1089/jmf.2006.257

17. Ramezani A, Nahad MP, Faghihloo E. The role of Nrf2 transcription factor in viral infection. J Cell Biochem. 2018;119(8):6366–6382. doi:10.1002/jcb.26897

18. Thimmulappa, Rajesh K et al. “Nrf2 is a critical regulator of the innate immune response and survival during experimental sepsis.” The Journal of clinical investigation vol. 116,4 (2006): 984-95. doi:10.1172/JCI25790

19. Chen, Xi et al. “Intercellular interplay between Sirt1 signalling and cell metabolism in immune cell biology.” Immunology vol. 145,4 (2015): 455-67. doi:10.1111/imm.12473

20. Senger, Donald R et al. “Activation of the Nrf2 Cell Defense Pathway by Ancient Foods: Disease Prevention by Important Molecules and Microbes Lost from the Modern Western Diet.” PloS one vol. 11,2 e0148042. 17 Feb. 2016, doi:10.1371/journal.pone.0148042

21. Corbi, Graziamaria & Conti, Valeria & Komici, Klara & Manzo, Valentina & Filippelli, Amelia & Palazzo, M & Vizzarri, Francesco & Davinelli, S & Costanzo, A & Scapagnini, Giovanni & Ferrara, Nicola & Donato, Casamassima. (2018). Phenolic Plant Extracts Induce Sirt1 Activity and Increase Antioxidant Levels in the Rabbit’s Heart and Liver. Oxidative medicine and cellular longevity. 2018. 10.1155/2018/2731289.



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