Introduction

During the COVID-19 pandemic, there have been many interests in using natural remedies that may aid in boosting the immune system to help combat and fight off the COVID-19 infection or to even prevent contracting the virus altogether. Several options, including vitamin C, vitamin D and elderberries, have been touted as possible natural remedies to help boost the immune system.

Are they effective and should you be taking them? Read on to find out more about them.

Elderberry: evidence in cold and flu duration

One possible natural remedy that has a long history of use in combating cold and flu is elderberry. It has been used since folk medicine to treat viral infections such as influenza and herpes simplex, due to its antiviral properties[1]. There have been studies done in the early 2000s to show effectiveness of elderberry in treating influenza infections as well[2]. There are also in vitro studies to show elderberry’s antiviral and antibacterial properties[3,4].

With world borders starting to open as COVID-19 measures eases across the different countries, more people will be traveling around by air and in airplanes. However, with the pandemic still highly prevalent in many countries, more care may need to be taken by individuals who are travelling, to prevent contracting of COVID-19 infection. Travellers may also be worried about catching other air-borne viruses such as influenza.

An Australian study conducted in 2016 seeks to answer the question of whether taking elderberry can prevent respiratory symptoms and infection duration. The authors concluded that the patients who took elderberry had a significant reduction in the duration and symptoms of cold in the air travellers. It was postulated that elderberry had such effects due to its antioxidant properties[5].

Other functions of Elderberry

Apart from its functions to boost immunity, elderberry extracts were also shown to be useful in certain health conditions, including diabetes[6], anti-inflammatory[7] and its effects on depression[8]. The many constituents in elderberry, such as the phenolic acids, anthocyanins, and vitamin C, also confer its antioxidant properties, which may have potential benefits in preventing diseases such as type 2 diabetes and cancers that occur due to oxidative stress[9].

What about Zinc and Vitamin C?

Zinc has been known to be important for the functions of multiple organs, ranging from the immune system, skeletal system, central nervous system to the gastrointestinal system. Deficiency in zinc in the body, especially in the growing stage, can lead to functional impairments such as impaired growth and development and risk of infections (e.g., diarrhoea, lung infections)[10]. Recommendations of zinc supplementation differ across different international guidelines and age groups, with the International Zinc Nutrition Consultative Group (IZiNCG) recommending up to 2.98mg per day[11], and the Food and Nutrition Board (FNB) of the Institute of Medicine (IOM) recommending doses up to 4.5mg per day[12]. The U.S. Food and Drug Administration (FDA) recommends a daily value (DV) of 11mg for adults and children above 4 years old[13].

Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that plays an important role in wound healing and controlling infections, such as the cold, which is probably one of the best-known functions of vitamin C. Research has also found that it has antioxidant properties, much like elderberry. It is also involved in the body’s immune system. The FNB recommends a daily vitamin C dietary allowance of up to 90mg for male adults[14].

Conclusion

Elderberry has gotten increasingly popular due to its multiple properties in being able to boost immune system and provides for anti-oxidant effects which is crucial for neutralising the many harmful free radicals we are exposed to in the modern-day society.

References

1. British Herbal Medicine Association: British Herbal Pharmacopoeia. Bournemouth: BHMA Publications, 1983; pp186 – 187.
2. Zakay-Rones Z, Thom E, Wollan T, Wadstein J. Randomized study of the efficacy and safety of oral elderberry extract in the treatment of influenza A and B virus infections. J Int Med Res. 2004 Mar-Apr;32(2):132-40. Available on: https://journals.sagepub.com/doi/10.1177/147323000403200205
3. Krawitz C., Mraheil M.A., Stein M., et al. Inhibitory activity of a standardized elderberry liquid extract against clinically-relevant human respiratory bacterial pathogens and influenza A and B viruses. BMC Complement. Altern. Med. 2011;11:182
4. Roschek B., Jr., Fink R.C., McMichael M.D., et al. Elderberry flavonoids bind to and prevent H1N1 infection in vitro. Phytochemistry. 2009;70:1255–1261.
5. Tiralongo E, Wee SS, Lea RA. Elderberry Supplementation Reduces Cold Duration and Symptoms in Air-Travellers: A Randomized, Double-Blind Placebo-Controlled Clinical Trial. Nutrients. 2016;8(4):182. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4848651/
6. Gray A.M., Abdel-Wahab Y.H., Flatt P.R. The traditional plant treatment, Sambucus nigra (elder), exhibits insulin-like and insulin-releasing actions in vitro. Nutr. 2000;130:15–20.
7. Badescu M., Badulescu O., Badescu L., Ciocoiu M. Effects of Sambucus nigra and Aronia melanocarpa extracts on immune system disorders within diabetes mellitus. Biol. 2015;53:533–539.
8. Mahmoudi M., Ebrahimzadeh M.A., Dooshan A., et al. Antidepressant activities of Sambucus ebulus and Sambucus nigra. Rev. Med. Pharmacol. Sci. 2014;18:3350–3353.
9. Hajhashemi V, Vaseghi G, Pourfarzam M, Abdollahi A. Are antioxidants helpful for disease prevention?. Res Pharm Sci. 2010;5(1):1-8. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3093095/
10. Roohani N, Hurrell R, Kelishadi R, Schulin R. Zinc and its importance for human health: An integrative review. J Res Med Sci. 2013;18(2):144-157. Available on: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3724376/
11. International Zinc Nutrition Consultative Group (IZiNCG). International Zinc Nutrition Consultative Group (IZiNCG) technical document #1. Assessment of the risk of zinc deficiency in populations and options for its control. Food Nutr Bull. 2004 Mar;25(1 Suppl 2):S99-203.
12. Food and Nutrition Board/Institute of Medicine. Washington DC: National Academy Press; 2002.
13. National Institutes of Health (NIH), Office of Dietary Supplements. Zinc: Fact Sheet for Health Professionals. 2021 December. Available on: https://ods.od.nih.gov/factsheets/Zinc-HealthProfessional/
14. National Institutes of Health (NIH), Office of Dietary Supplements. Vitamin C: Fact Sheet for Health Professionals. 2021 March. Available on: https://ods.od.nih.gov/factsheets/VitaminC-HealthProfessional/