5 Best Immune System Boosters to Ward off Cold and Viral illness

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Now that fear of coronavirus is widespread, the least we can do is try keep ourselves as healthy as possible. To do that, we need to incorporate these 5 best immune system boosters in our daily life.

Under the fear of coronavirus pandemic worldwide, people have started searching online about way to boost the immune system. Are there any supplements or foods to boost your immune system?

As the name suggest, the immune system-is a system, not a single entity. It is a complex network of cells, organs and tissues that work together to fight the invasion of foreign body into your system.

During flu or viral season, you may have noticed that some people get sick more often than other. Have you ever wondered, why some people are more prone to catching viral infection or cold while other stand still with full menu of viruses surrounding them in form of sick colleagues or family members?

It’s all about strength of your immune system. A person with weak immune system is likely to get more frequently infections than others, and also, these illnesses might be harder to treat.

The strength of an immune system is largely determined by the germs that we are exposed to over time and factors such as diet, stress, sleep, exercise, and digestion (1).

Spoiler alert … there is no magic pill or food that boost your immune system and protect you from novel coronavirus or other viral infection overnight.

Don’t worry, it is still possible to naturally boost your immune system and its easier than you think.

Without a further ado, lets look at these 5 best immune system boosters to ward of cold and viral infection.

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1. Improve your Sleep habits:

Getting good quality sleep at night every day is important to keep you healthy and function well throughout the day. A healthy immune system function well to ward of infection.

Immune system releases proteins called cytokines when you are asleep. These cytokines are increased in your body when you are infected with virus or bacteria. Not getting enough sleep or quality sleep may decrease the production of these cytokines and increase your susceptibility to viral infection.

Research studies (2-5) show that people who don’t get enough quality sleep are more likely to get sick after being exposed to a virus, such as a common cold virus.

One study published in JAMA showed that healthy participants who slept a minimum of eight hours each night over a two-week period showed a greater resistance to the viral infection compared to those who slept seven hours or less each night after viral exposure (6).

Lack of sleep can also affect how fast you recover if you do get sick. Also, getting enough sleep is important if you have been exposed to virus.

The optimal amount of sleep for most adults is 7 to 8 hours each night. Teenagers need 9 to 10 hours of sleep. School-aged children may need 10 or more hours of sleep.

2. Eat a well-balanced diet


The balanced diet is high in vitamins, minerals and other nutrients and low in unnecessary fat and sugar. A well-balanced diet supports the healthy immune system.

The well-balanced diet includes leafy green vegetables, fruits, seeds and nuts. They are loaded with nutrients that are essential to keep the immune system healthy as well as controls weight gain. Consuming them on a daily basis boosts the immunity.

For a healthy liver, cruciferous vegetables like Kale, Broccoli and Cabbage should be included in daily diet. These vegetables are a major source of glutathione, which triggers the toxin cleansing enzymes of the liver. Healthy liver ensures the body’s natural detoxification process (7).

Also, eating cruciferous vegetables helps the immune system to fight intestinal pathogens. According to a research study done on mice model, eating cruciferous vegetables boosts specific cell surface proteins necessary for proper immune system functions. And mice deprived of cruciferous vegetable lost significant amount of cell-surface proteins (8).

3. Exercise Daily


Including moderate intensity exercise in your daily routine – like brisk walking for 30 min, can help maintain a healthy immune system. Research continues to support a link between moderate, regular exercise and a healthy immune system.

Moderate exercise cause immune cell to circulate through the body more quickly and enable them to kill virus and bacteria. Although, after exercise, the immune system returns to normal state in few hours. But if you include moderate exercise in your daily routine, a cumulative effect leads to a long-term immune response (9).

Research study published in J Sport health Sci showed that those who perform a moderate-intensity walk for 40 minutes per day had half as many sick days due to colds or sore throats as those who don’t exercise (10).

4. Lower Stress level

Stressed immune system can not perform to its best of ability to fight off the infection.

The chronically stressed people are more susceptible to infection because of constant release of the hormone cortisol suppressing the immune system by lowering the number of lymphocytes.

Stress is also linked to headaches; infectious illness (e.g. ‘flu); cardiovascular disease; asthma; gastric ulcers and diabetes (11-13).

Finding an effective way to regulate personal stress may go a long way toward better overall health. Try practicing yoga or meditation to relieve stress (14).

5. Check your Vitamin D level

Vitamin D helps our immune systems stay balanced during the cold and flu. Few promising research studies have shown that checking your vitamin D level and taking a Vitamin D supplement could help to fight off cold and flu.

A recent study of 25 randomized controlled trials showed an overall protective effect of vitamin D supplementation against acute respiratory tract infections. This study suggested that taking vitamin D daily or weekly was more effective than larger doses taken in single or monthly boluses. The most common daily dose used was vitamin D3 300-4,000 IU (15).

Another recent randomized, double-blinded, placebo-controlled trial of 5110 adults showed that monthly high-dose vitamin D supplementation does not prevent acute respiratory infections in older adults with low levels of vitamin D (16).

The National Institutes of Health has also suggested that low vitamin D levels are associated with frequent colds and influenza. However, there is no recommended dose of vitamin D for healthy immune system (17).

If you are concerned about your immune health, talk to doctor about checking your vitamin D level. Good sources of vitamin D can be found in food such as egg yolks, mushrooms, milk and food fortified with vitamin D. You can also buy vitamin D supplements at your local grocery store or pharmacy. Choose supplements that contain D3 (cholecalciferol), since it’s better at raising your blood levels of vitamin D.

Supplements to Boost your Immune System

This is the most searched hot topic on social media amid the current pandemic of novel coronavirus.

The common food such as ginger, garlic, turmeric, chicken broth, citrus fruit are touted for their immune boosting properties. They are good for your immune system and can help contribute to a well-balanced diet. But increasing the amount of ingestion amid the coronavirus fear may not help you against infection.

Supplements such as vitamins B6, C, and zinc are also touted as an immune booster lately. There are several studies that shows the benefit but strong evidence on its effectiveness is still lacking.

In 2013, review of several studies showed that vitamin C supplements taken during cold can reduce the duration of illness by 8% in adults and 14% in children meaning that supplementing vitamin C can reduce the duration of colds by about one day (18).

Meta-analysis of several randomized controlled trials have shown that zinc lozenges may reduce the duration of cold by about a day and, may reduce the number of upper respiratory infections in children (19).

If you are lacking in one of these vitamins or zinc, then taking supplements may help your immune system but if you already have enough from your diet, its not clear that taking supplement can help. Supplement may cause side effects.

Also, several supplements marketed for their immune boosting properties should be used with caution. Dietary supplements are not evaluated by FDA and manufacturer can place the product on the market without providing proof of its safety and efficacy.

If you’re considering taking extra vitamins to help your immune system, check with your healthcare provider, because it can interfere with your medication.

Having said that, if you enjoy taking foods touted as immune booster, there is no harm in doing so. I personally like to sip on ginger tea whenever I suffer from common cold or flu. But when it comes to preventing yourself from viral illness, do not neglect – washing your hands frequently, do no touch your face and covering your mouth with elbow when sneeze.

What Weakens Your Immune System?

Sometimes we are responsible for our weak immune system because of our habits. Some of these habits includes;

  • Too much sugar in your diet
  • Excessive Alcohol consumption
  • Smoking
  • Dehydration
  • Obesity
  • Taking too many antibiotics
  • Stress
  • Not getting enough sleep
  • Loneliness
  • Depression

Final Word

Keeping your immune system strong is not as hard as you might think it is. With little change in your diet and lifestyle, you can ensure that your immune system is strong enough to protect you against the viral illnesses.

Now, Over to you!! What do you do to boost your immune system? Leave a comment below.



  1. Brodin P, Jojic V, Gao T, et al. Variation in the human immune system is largely driven by non-heritable influences. Cell. 2015;160(1-2):37–47. doi:10.1016/j.cell.2014.12.020
  2. Cirelli C. Definition and consequences of sleep deprivation. http://www.uptodate.com/home. Accessed May 27, 2015.
  3. Cedernaes J, et al. Determinants of shortened, disrupted, and mistimed sleep and associated metabolic health consequences in healthy humans. Diabetes. 2015;64:1073.
  4. How sleep deprivation affects your heart. National Sleep Foundation. http://sleepfoundation.org/sleep-news/how-sleep-deprivation-affects-your-heart. Accessed May 27, 2015.
  5.  Prather AA, Janicki-Deverts D, Hall MH, Cohen S. Behaviorally Assessed Sleep and Susceptibility to the Common Cold. Sleep. 2015;38(9):1353–1359. Published 2015 Sep 1. doi:10.5665/sleep.4968
  6. Cohen S, et al. (2009). Sleep habits and susceptibility to the common cold. DOI:doi.org/10.1001/archinternmed.2008.505
  7. Guan YS, He Q. Plants Consumption and Liver Health. Evid Based Complement Alternat Med. 2015;2015:824185. doi:10.1155/2015/824185
  8. Li, Ying et al. Exogenous Stimuli Maintain Intraepithelial Lymphocytes via Aryl Hydrocarbon Receptor Activation. Cell, Volume 147, Issue 3, 629 – 640
  9. Nieman DC, Henson DA, Austin MD, Brown VA. The Immune Response to a 30-Minute Walk. Med Sci Sports Exerc 37:57-62, 2005.
  10. Nieman DC, Wentz LM. The compelling link between physical activity and the body’s defense system. J Sport Health Sci. 2019;8(3):201-217. doi:0.1016/j.jshs.2018.09.009
  11. Brady, J. V. (1958). Ulcers in” executive” monkeys. Scientific American.
  12. Edwards, K.M., Burns V.E., Reynolds, T., Carroll, D., Drayson, M., & Ring, C. (2006). Acute stress exposure prior to influenza vaccination enhances antibody response in women. Brain, Behavior, and Immunity, 20:159-68.
  13. Glaser, R., Sheridan, J. F., Malarkey, W. B., MacCallum, R. C., & Kiecolt-Glaser, J. K. (2000). Chronic stress modulates the immune response to a pneumococcal pneumonia vaccine. Psychosomatic Medicine, 62, 804-807.
  14. Cohen S, et al. (2012). Chronic stress, glucocorticoid receptor resistance, inflammation, and disease risk. DOI: doi.org/10.1073/pnas.1118355109
  15. Martineau AR, Jolliffe DA, Hooper RL, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017­;356:i6583.
  16. C A Camargo, JSluyter et al, Effect of monthly high-dose vitamin D supplementation on acute respiratory infections in older adults: A randomized controlled trial. Clin Infect Dis. https://academic.oup.com/cid/advance-article-abstract/doi/10.1093/cid/ciz801/5550911?redirectedFrom=fulltext. Published August 17, 2019. Accessed September 20, 2019.
  17. NIH website. https://www.nih.gov/news-events/nih-research-matters/low-vitamin-d-levels-associated-colds-flu. Published March 9, 2009. Accessed September 14, 2019
  18. Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.: CD000980. DOI: 10.1002/14651858.CD000980.pub4.
  19. Science, M., Johnstone, J., Roth, D. E., Guyatt, G., & Loeb, M. (2012). Zinc for the treatment of the common cold: a systematic review and meta-analysis of randomized controlled trials. CMAJ : Canadian Medical Association journal = journal de l’Association medicale canadienne, 184(10), E551–E561. https://doi.org/10.1503/cmaj.111990
  20. Image by silviarita from Pixabay


6 thoughts on “5 Best Immune System Boosters to Ward off Cold and Viral illness”

  1. Thank you so much!! very informative post and good timing as now every one should take step to boost their immunity to fight off coronavirus.

  2. Your blog is very informational. THank you. I agree that supplement shouldn’t be taken unless you are deficient. But vitamin c do help when you are sick. Keeping ourself healthy, washing our hand and social distancing are the only option we have to to boost our immune system.

    1. Thank you for the comment, Lily. Research has shown that Vitamin C helps shorten the cold by 1 day. So taking it while you are sick may help you. But taking supplements to prevent cold or viral illness is baseless.

  3. Prakash Prajapati

    Very informative,thank you. Keeping up with your health and social distancing is the only answer to coronavirus crisis world facing right.

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