The immune system and COVID-19

Our body needs a healthy immune system to defend itself against germs. In the midst of the COVID-19 pandemic and flu season, you need a healthy immune system more than ever. 

Tereza Hubkova, MD, ABIHM, ABIM, is an integrative medicine physician at AdventHealth Shawnee Mission. According to Dr. Hubkova, our immune system is strongly influenced by our lifestyle: the foods we eat, how we sleep, our physical activity and even our mood and level of stress. 

Proper nutrition is key. You want to make sure your diet provides all the nutrients your immune system needs and that your body is not in a pro-inflammatory state in case you would catch COVID. 

The life-threatening complication of COVID, the “cytokine storm”, happens when the immune system goes into overdrive and the immune response itself causes too much “collateral” damage. Our Western diet full of processed foods, sugar, salt and unhealthy fat puts many Americans at risk. Instead, we need fresh produce full of vitamins and colorful polyphenols, minerals, fiber, protein and healthy fats (including omega 3 fatty acids from seafood).

Our age affects our immune system as well – children and young adults are less likely to be affected by COVID than older people. 

“Even just one night of poor sleep severely impairs our ability to deal with viruses,” said Dr. Hubkova. “When partially sleep deprived, we produce 75 percent less natural killer cells that could eliminate viruses. As we get older, we also produce less melatonin, a hormone crucial for a healthy immune system. Stress and blue light from our electronic screens suppress melatonin production as well.” 

Dr. Hubkova also advises to be sure your Vitamin D level is in the optimal range. 

“Patients in intensive care due to severe COVID almost always have low vitamin D level,” said Dr. Hubkova.  

We make Vitamin D in our skin when we are exposed to sunshine, but our modern indoor lifestyle means that Vitamin D deficiency is extremely common. We do not get much Vitamin D from food, so besides spending more time outdoors, taking a Vitamin D supplement may be the next best solution, especially in the winter.

Between the COVID pandemic and cold weather, many people are not getting out much and interacting with others, which is likely contributing to anxiety and depression and affecting our immune system as well.

“Our immune system has receptors for the molecules of emotion,” said Dr. Hubkova. “It knows when we are happy or sad, and it works much better when we are in a positive state of mind.”

Finally, is there any advice for COVID vaccination? 

In general, we do not respond well to vaccines when our immune system is weakened, such as by stress or sleep deprivation,” said Dr. Hubkova. “While we do not know everything about the COVID vaccine yet, try to get a good night’s sleep the night before you get vaccinated.”

Dr. Hubkova has created the 21-day immunity challenge designed to get your immune system in better working order by addressing a few key lifestyle habits, one day at a time. Learn more about the 21-day immunity challenge at