By Tee Villanueva

How has 2020 been for you? 

Because frankly, the year 2020 started well for most of us, but before it has finished its first quarter, the world came to a halt. 

Image by Bruno /Germany from Pixabay

The COVID-19 outbreak has affected all of us. Young and old, both are affected by this disease. The easy spread of COVID-19 has made this pandemic difficult to contain. 33 million people worldwide have been infected with almost 1 million deaths. 

Our role in this pandemic is to make sure that we do not allow ourselves to become a part of the chain of infection. By reducing our exposure, following health protocols, and keeping our immune system at its best, we prevent the spread of this virus. 

Our immune system plays a vital role in this pandemic. It is in charge of fighting off bacteria, viruses, parasites, fungi, and other germs that cause disease. (1) 

Aside from this, it is also tasked to recognize and immediately neutralize substances that enter the human body. The immune system is composed of two subsystems – the innate immune system and the adaptive immune system.

The innate immune system is a hard-wired response system as it recognizes molecular patterns based on the encoded data on the genes passed on from the hosts’ germline. (2) It acts to recognize pathogens immediately and acts to eliminate it rapidly.

The adaptive immune system, on the other hand, responds to specific pathogens, allergen, or toxin only after it has been recognized by the body as an antigen. (2) 

Unlike the innate immune system, the adaptive immune system requires time before it responds to the antigen. The adaptive immune response produces cells that would be dormant unless the same antigen invades the human body.

If the body’s immune system is working properly, one would not be affected by pathogens but maintaining the immune system in a good shape is not the body’s work alone. 

To aid our body in fighting off diseases, we must play a role in strengthening our immune system.

First off, we have to eat the food that supports the immune system! 

Eating nutrient-dense food is the right way to go. The food that we want is not always the food that we need. Food that best supports our body needs to have the right vitamins and minerals.

Vitamin C 

One essential micronutrient needed to boost our immune system is vitamin C. This vitamin is not produced by the body, hence, we need to consume food rich in vitamin C. Dietary sources of vitamin C include citrus fruits, strawberries, leafy vegetables, broccoli, green and red peppers, and tomatoes. (3)

Vitamins C functions as an antioxidant and cofactor, a catalyst in enzymatic reactions. (4) Its role in the immune response is through maintaining the skin barrier integrity, aid in wound healing, and leukocyte function. (4) 

Vitamin C maintains the skin barrier integrity by enhancing collagen synthesis and further stabilizing the collagen. It also protects the body from reactive oxygen species. Identification of microbial invasion and its killing is enhanced by vitamin C. 

Vitamin A

Another micronutrient that is crucial in its role in maintaining vision, promoting growth and development is vitamin A. (5) Vitamin A also functions to protect the skin and mucus membranes in the body. Dietary sources of vitamin A include dairy, liver, fish, carrots, broccoli, squash, and fortified cereals. (6)

Vitamin A’s role in the immune system starts at the forefront. Vitamin A plays a vital role in the formation of the epithelium of the skin and mucus membranes, more so in the respiratory tract. (5) 

It is also important as it influences the differentiation of the immune cells. Without vitamin A, immune cells would not develop and differentiate properly. Vitamin A also has a role in T-cell migration and its regulation and homeostasis. 

Vitamin D

Vitamin D is often associated with calcium and bone homeostasis but aside from these functions, vitamin D also plays a role in immune system defense. Vitamin D is often found in food such as fish, meat, milk, eggs, mushrooms, dairy, and vitamin D fortified food. (7)

In the immune system, vitamin D plays a part in the innate immunity as it is essential in the transcription of innate antimicrobial response elements such as cathelicidin. (8) Vitamin D also influences the production of anti-inflammatory and inflammatory mediators. Proper supplementation of vitamin D would significantly strengthen the immune system. 

Copper and Zinc

Copper and zinc are two essential metals needed to maintain the optimal innate immune function. (9) Deficiency of copper and zinc are associated with increased susceptibility to bacterial infections. Zinc is often found in oysters, veal, beef, pork, and lamb, while food sources rich in copper are nuts and seeds, chocolates, shellfish, and organ meats. (10) 

Copper’s role in the immune system involves leukocyte differentiation, maturation, and proliferation. (9) In states of deficient copper supplementation, impaired neutrophil and macrophage function is noted. 

Zinc, like copper, is also needed for the immune system to properly function. Normal development and activity of cells involved in both innate and acquired immunity are associated with a proper zinc supplement. (9) Zinc deficiency is associated with impaired phagocytosis and intracellular killing of pathogens.

The importance of having a balanced diet that supplements our body with all the nutrients needed couldn’t be stressed enough. In this time of the pandemic, our health needs to come first and by eating the right food, we strengthen our immune system.

Enough sleep

Aside from eating right, we have to allow our bodies to have enough time to recuperate. Sleep is a physiological process that allows our body to develop, conserve energy, clear brain waste, modulate immune responses, cognition, performance, and psychological state. (11)  

Sleep and the circadian rhythm are strong regulators of the immune process. (12) Immune responses are highly influenced by the sleep-wake cycle. Innate immune factors peak at the waking hours to effectively combat infections, while undifferentiated cells and naïve T cells often peak during the night. (12)

Formation of long-term immunologic memory is enhanced with sleep, hence its peak. 

With the right amount and quality of sleep, we allow our body to heal and function at its best especially in this pandemic. One way to strengthen our immune system is through good sleep hygiene.


Exercise is a boost to our bodies. With the world put into a halt, we have to find ways to regularly exercise without compromising our safety and exposure to the virus. 

It is suggested that we engage in moderate to vigorous-intensity exercise to directly influence our immune system. (13) The effect of a moderate to vigorous-intensity exercise influences the secretion of different cells that aid in immune function. Moderate to vigorous exercises that could engage in are as follows:

  • Brisk walking (4 mph)
  • Riding a bicycle (10-12 mph)
  • Hiking uphill
  • Jogging at 6 mph
  • Swimming
  • Jumping rope
  • Aerobics

The recommended amount of exercise to maintain a healthy body is at 150 minutes of moderate-to-vigorous exercise per week. With our time spent working from home, this won’t take up much of our time. So, allow your body to fight against infections by exercising. 

Our health is currently the priority in this pandemic and to effectively combat COVID-19, we have to alter our lifestyle to support our body’s needs. This can only be achieved through eating right, having good sleep hygiene, and by exercising regularly. 



  1. Institute for Quality and Efficiency in Health Care (IQWiG). (2006). How does the immune system work? Retrieved from:
  2. Chaplin D. D. (2010). Overview of the immune response. The Journal of allergy and clinical immunology, 125(2 Suppl 2), S3–S23.
  3. Chambial, S., Dwivedi, S., Shukla, K. K., John, P. J., & Sharma, P. (2013). Vitamin C in disease prevention and cure: an overview. Indian journal of clinical biochemistry : IJCB, 28(4), 314–328.
  4. Carr, A. C., & Maggini, S. (2017). Vitamin C and Immune Function. Nutrients, 9(11), 1211.
  5. Huang, Z., Liu, Y., Qi, G., Brand, D., & Zheng, S. G. (2018). Role of Vitamin A in the Immune System. Journal of clinical medicine, 7(9), 258.
  6. National Institute of Health: Office of Dietary Supplements. (2020). Vitamin A. Retrieved from,squash%20%5B4%2C5%5D.
  7. Jungert, A., Spinneker, A., Nagel, A., & Neuhäuser-Berthold, M. (2014). Dietary intake and main food sources of vitamin D as a function of age, sex, vitamin D status, body composition, and income in an elderly German cohort. Food & nutrition research, 58, 10.3402/fnr.v58.23632.
  8. Aranow C. (2011). Vitamin D and the immune system. Journal of investigative medicine : the official publication of the American Federation for Clinical Research, 59(6), 881–886.
  9. Djoko, K. Y., Ong, C. L., Walker, M. J., & McEwan, A. G. (2015). The Role of Copper and Zinc Toxicity in Innate Immune Defense against Bacterial Pathogens. The Journal of biological chemistry, 290(31), 18954–18961.
  10. Ma, J., & Betts, N.M. (2020). Zinc and copper intakes and their major food sources for older adults in the 1994-96 continuing survey of food intakes by individuals (CSFII).The Journal of Nutrition, 130(11), 2838-2843.
  11. Zielinski, M. R., McKenna, J. T., & McCarley, R. W. (2016). Functions and Mechanisms of Sleep. AIMS neuroscience, 3(1), 67–104.
  12. Besedovsky, L., Lange, T., & Born, J. (2012). Sleep and immune function. Pflugers Archiv : European journal of physiology, 463(1), 121–137.
  13. Nieman, D. C., & Wentz, L. M. (2019). The compelling link between physical activity and the body’s defense system. Journal of sport and health science, 8(3), 201–217.


About the author:

Tee Villanueva always had her interest focused in writing. She has worked as a creative and content writer even while in medical school. Currently, she is a licensed resident doctor in Internal Medicine but loves that through writing, she can provide information about complex diseases and treatments to the general public.