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The Science Behind Your Immune System  &  How to Keep it Strong
Vitamins & Supplements
The Science Behind Your Immune System & How to Keep it Strong
Lindsey Toth, MS, RD • August 5, 2020

We often talk about how we want to maintain healthy immune systems—for overall wellness, to fend off seasonal woes and to live longer and healthier lives. But do you understand how this important bodily system works on a biological level?

Knowledge is power, after all, so in this article, we’re breaking down the science behind your immune system, plus healthy habits and immune support supplements that can help your immune system function optimally.

What Exactly is the Immune System?

The immune system is a network of specialized cells, organs, proteins and tissues in your body responsible for protecting you from external biological influences.1 It has the innate ability to distinguish between your tissue and foreign tissue, and it can even recognize and eliminate dead or faulty cells. Supporting the health of your immune system is the best way to ensure that it can do its job.

White Blood Cells and the Immune System

White blood cells are a critical component of the immune system. Also known as leukocytes, white blood cells circulate through your blood vessels and lymphatic vessels, always on the lookout.2 When they spot something that doesn’t belong, they multiply to increase your body’s natural defenses and send signals to other cells in your body to do the same thing.

There are two main types of white blood cells—phagocytes and lymphocytes. Phagocytes are responsible for keeping you healthy and fighting invaders. Meanwhile, lymphocytes are like your immune system’s memory—remembering what has happened in the past and building up defenses for future wellbeing. Lymphocytes help you develop more immunity as you age.

White blood cells are stored in your lymphoid organs, which include your thymus, spleen, bone marrow, lymph nodes, lymphatic vessels, Peyer’s patches, adenoids and tonsils.3

How the Immune System Works

When white blood cells detect non-native proteins on the surface of cells in your body, they launch an immune response. Antibodies are released to help keep you healthy, processing and eliminating the non-native proteins from your system.

Unfortunately, your immune system faces challenges daily. Many factors can impact immune health—how much you sleep, the foods you eat, your age, your lifestyle choices and even the weather. While you can't control everything, it's important to make an effort to support your immune health where you can.

How to Keep Your Immune System Healthy & Happy

Lucky for you, there are plenty of ways to help keep your immune system in prime working order on a daily basis.4 Here's a quick rundown of some of the best, immune-supporting habits and supplements.

Healthy Habits for Immune Support

  • Exercise: There are several theories as to why taking a daily walk or getting your sweat on a few times each week can boost your immune system.5 One, in particular, suggests that exercise can help white blood cells circulate through your body more efficiently, thus improving the overall work of your immune system.
  • Sleep: When you sleep, your immune system releases special proteins that it uses to fight foreign invaders. When you’re sleep-deprived, your body doesn’t produce enough of these proteins, leaving your immune system more vulnerable.6 So prioritize an adequate amount of rest each night to keep your immunity high.
  • Diet: Research suggests that a balanced diet is vital to a healthy immune system. Protein deficiency and a lack of micronutrients including zinc, selenium, iron, copper, folic acid, vitamin A, vitamin C, vitamin E and vitamin B6 all reduce immunity.7 One of the easiest way to source these nutrients is to follow a predominantly plant-based diet and load up on fruits and vegetables at every meal. Take a multivitamin to fill nutrient gaps.
  • Stress: Researchers estimate that stress accounts for between 75% and 90% of all visits to the doctor, so it's important to take steps regularly to reduce stress.8 Read Say Om: 6 Tips to Help You Relax and Reduce Stress for some great ideas.

Supplements that Support Immune Health

  • Elderberry is a time-honored favorite of European herbalists. It’s an immune system tonic that can help bolster your body's defenses. Studies have found that elderberry can supply the body with additional antioxidants, boosting its natural immune response and helping it recover more quickly.9
  • There’s also a wide variety of immune support mushrooms that assist this important system in your body. Mushrooms have been used to make health tonics in Eastern medicine for thousands of years, serving as sidekicks to the immune system.10 Reishi, chaga and cordyceps are a few of the most popular mushrooms consumed in the name of immune health.
  • Probiotics are also incredibly important for immunity. A solid 70 percent of your immunity stems from your gut, so keeping your digestive system happy is a win for your immune system as well.11

If you found this article to be helpful, you might also enjoy 22 Vitamins and Supplements for Immune Health and Benefits of Elderberry. Also, be sure to sign up for Swanson Health Emails to get expert wellness advice and our best promotions in your inbox.

Lindsey Toth, Swanson Health Products

About Lindsey Toth, MS, RD
Registered Dietitian, Swanson Health Products

Lindsey is a nationally-recognized registered dietitian and nutritionist with a soft spot for pie. She empowers people to take charge of their health by finding the balance between the pleasure and nourishment in food.

Her philosophy is that you should take care of your body because it’s the only permanent home you have. It’s what inspired her to pursue a career in nutrition and, ultimately, led her to Swanson Health.


1 How the Immune System Works. Medical News Today. https://www.medicalnewstoday.com/articles/320101.php

2 How Does the Immune System Work? National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/books/NBK279364/

3 The Immune System. Johns Hopkins Medicine. https://www.hopkinsmedicine.org/health/conditions-and-diseases/the-immune-system

4 How to Boost Your Immune System. Harvard Health Publishing. https://www.health.harvard.edu/staying-healthy/how-to-boost-your-immune-system

5 Exercise and immunity. Medline Plus. https://medlineplus.gov/ency/article/007165.htm

6 Lack of sleep: Can it make you sick? Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/insomnia/expert-answers/lack-of-sleep/faq-20057757

7 Nutrition and the immune system: an introduction. National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/pubmed/9250133

8 The Effects of Stress on Your Body. WebMD. https://www.webmd.com/balance/stress-management/effects-of-stress-on-your-body

9 Elderberry: A Natural Way to Boost Immunity During Cold and Flu Season? Cleveland Clinic. https://health.clevelandclinic.org/elderberry-a-natural-way-to-boost-immunity-during-cold-and-flu-season/

10 6 Mushrooms That Act as Turbo-Shots for Your Immune System. Healthline. https://www.healthline.com/health/food-nutrition/best-medicinal-mushrooms-to-try

11 Vighi G, et. al. Clinical & Experimental Immunology. 2008 Sept. doi: 10.1111/j.1365-2249.2008.03713.x. U.S. National Library of Medicine National Institutes of Health. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2515351/

*These statements have not been evaluated by the Food and Drug Administration. These products are not intended to diagnose, treat, cure or prevent any disease