How to Support your Healthy Immune System

How to Support your Healthy Immune System

While seeing patients in my medical practice, I spend a lot of time explaining to them, in simple and memorable terms, why it’s important to pay more attention to keeping their immune system healthy.  Some of the most important fighters in your immune system army (ISA) inside are called natural killer cells (“NK cells”).  NK cells are called “natural” because, unlike other immune cells, they are already preprogrammed to attack germs at first recognition.  Other troops in your immune system army need prior exposure to be activated (the principle on which vaccines are developed), like what happens when you build-up immunity to a flu virus only after previously getting it. 

Consider NK cells as the Navy Seals of your ISA. When an NK cell finds a germ, it gloms onto it.  It then shoots biochemical darts (appropriately called perforins) to literally poke holes into the germ and injects dissolving enzymes, called granzymes, into the germ cell to kill it.  The defeated and deflated germ cell then becomes cellular garbage, which is removed by macrophages (“big eaters”), your immune system’s garbage-collectors. 

You are probably wondering, “How do I get them to fight better for me?” Imagine if you were designing your immune system army, especially your NK cells, where would you station your NK cells so they could be quickly mobilized?  Answer: the lining of your blood vessels, the endothelium, which you learned about in my previous several articles.  This makes sense.  Being stationed in the lining of your blood vessels allows your NK cells to quickly enter the bloodstream and travel anywhere in your body to trigger the immune response and defend itself.

Movement mobilizes your immune system.

Exercise increases both the number and “killing ability” – called “cytolytic strength” – of your NK cells.  In a nutshell, movers have a higher number of NK cells and a smarter immune system army than do sitters.  If your NK cells could talk, they would say, “Move us more and we’ll fight better for you.”  Imagine taking a brisk walk with friends and boasting, “I’m mobilizing my natural immune system army inside!” 

Let’s go a little deeper and visualize how you mobilize your ISA during exercise.  When you exercise, you increase the blood flow across your endothelium where much of your ISA is stationed.  Using immunospeak, this is called demargination.  Imagine your increased blood flow across your endothelium grabbing your ISA troops and saying: “Come on into the bloodstream and let’s travel all over the body where you’re needed to fight germs.”  As I have emphasized in many of my previous articles, exercise is like opening your own internal pharmacy inside, in addition to mobilizing your ISA.  Think: the fitter you become, the fitter your immune system becomes. 

Feed your NK cells and they’ll fight better for you.  Like any troops, the better you feed them, the better they fight.  Dr. Mom advised: “Put more color on your plate” because colorful foods are rich in antioxidants, which help feed your ISA. 

Nutritional supplements your NK cells like.  In delving into some fascinating research, I discovered a study at Washington State University where a team of immune system researchers fed volunteers two to eight milligrams of astaxanthin a day for eight weeks, after which they found an overall improvement in the markers of immune system health, especially an increased level of NK cells*. 

In summary, to get your immune system army to fight better for you, eat real foods; move more, sit less; and take science-based supplements that help, such as Hawaiian Astaxanthin, to support a healthy immune system*.

Consult your healthcare provider before starting a new diet, exercise or health program. 

*These Statements have not been evaluated by the Food and Drug Administration.  This product is not intended to diagnose, treat, cure, or prevent any disease.


Park, J.S., et al. (2010).  Astaxanthin decreased oxidative stress and inflammation and enhanced immune response in humans. Nutrition and Metabolism. March 5; 7:18.

Natural Astaxanthin, Hawaii’s Supernutrient, by William Sears, M.D., 2015.

Help Heal Yourself From Cancer, by William Sears, M.D., and Martha Sears, R.N., 2022.