In 2020, the world has been hit by the newfound coronavirus threat – COVID-19. The public is paying more attention to the everyday-newly-confirmed-cases of COVID-19 as the spread of this virus in an alarming rate stoke fear and tension among the public.
Apart from coronavirus, influenza (commonly known as the flu) has also caused a considerable number of morbidity and mortality globally. According to a review article published in the Medical Journal of Malaysia, influenza is generally happening all year round in Malaysia with no clear seasonal trends.1
Although there are anti-viral medications such as oseltamivir and zanamivir for treatment of influenza infection, there is no known vaccination available to control coronavirus up to this moment. By looking at the latest data of global cases affected by COVID-19, children and elderly with underlying diseases such as diabetes, heart health issues as well as asthma are no longer the only vulnerable one. Both coronavirus and influenza affected all age group. Thus, maintaining a strong body’s immune system is crucial in fighting against disease-causing germs like bacteria, viruses, parasites or fungi.
Here, other than the popular Vitamin C, we are compiling evidence-based ingredients that possess anti-viral effects through regulating and strengthening our body’s defence system to better curb with these infections.
Colostrum is the first milk produced by all mammals for their new-borns during the first few hours after birth. The thick, sticky and yellowish liquid is exceptionally high in antibodies such as immunoglobulin (Ig) and antimicrobial peptides (lactoferrin and lactoperoxidase) which are important for immunological protection.2,3
A study indicated that colostrum supplementation improved the immune response to influenza A (H1N1) virus infection in mice by increasing the natural killer (NK) cells which recognize infected cells and destroy it.4 The immunoglobulin G (IgG) found in colostrum also showed to be successful in alleviating the symptoms of influenza in pre-treated mice by reducing the viral load.5
We all heard about the goodness of probiotics. Thanks to the probiotic drinks such as Yakult and Vitagen that are readily accessible in the market. Probiotics are the ‘good’ and live bacteria that found abundantly in our gut. One of the key functions of probiotics is regulating the body’s immune system by competing with pathogens and toxins for adherence to the intestinal lining wall.6 Lactobacillus and Bifidobacterium are two extensively studied probiotics used in human and animals. On the other hand, prebiotics such as inulin act like food for these ‘good’ bacteria that help to promote the growth of beneficial bacteria in the gut. Thus, when used in conjunction, the probiotics and prebiotics seem to have a synergistic effect.
A study demonstrated that the intake of probiotics reduced the incidence of acquiring common cold as well as reducing the number of days with common cold symptoms in healthy subjects.7 Another human study investigated on the effects of probiotic supplementation on adult volunteers who have contracted the common cold 4 or more times in the past year found the similar result as the previous study and further suggested that probiotics are safe and effective for fighting the common cold and influenza-like respiratory infections by boosting the immune system.8
Edible bird’s nest is a popular traditional Chinese medicine made from the saliva of swiftlets. Due to its remarkable nutritional composition, the food has been labelled as a luxurious and precious food tonic among Chinese. It composed of carbohydrates, proteins, fatty acids, hormones and minerals that help in improving overall general health including regulating the immune function.
Sialic acid is one of the active constituent found in edible bird’s nest which serve a significant role in anti-viral properties. Studies found that sialic acid disrupted the influenza A and the highly pathogenic avian influenza (H5N1) virus life cycle and inhibited the attachment of the virus to the cellular receptor which effectively reduced viral reproduction.9,10 Edible bird’s nest is also shown to reduce the intestinal immune injury caused by a medication (cyclophosphamide) used as chemotherapy to suppress the immune system by enhancing the production of immune B cells and antibodies secreted by B cells.11
Ginseng is a traditional medicine that has a long history in China, Korea and Japan. It is also one of the most widely used herbs in western countries such as the United States. Numerous research suggested ginseng as a potent natural remedy due to its anti-inflammatory, anti-cancer, anti-viral and anti-ageing properties.12 Most of the pharmacological actions of ginseng are due to the presence of its health-promoting active constituents such as ginsenosides and polysaccharides.
Ginseng polysaccharide was showed to lower the lung viral and improve the survival rate of mice against H1N1 influenza viruses by stimulating the macrophage cells which are responsible for destroying pathogens.13 Similarly, another study demonstrated that ginsenoside aids in providing protection against influenza virus infection through the activation of macrophages which promote tissue repair and healing during recovery from influenza infection.12
Cordyceps also named as “winter-worm summer-grass” by Chinese as it is an insect parasitizing fungus, normally inhabits on the surface of insects pupae in winters and leading to the formation of the fruiting body in the summers.14 It has been used for diverse medicinal purposes including treatment of kidney illnesses, fatigue, cough, soothe the lung and expel phlegm.15
Available evidence demonstrated the natural Cordyceps sinensis as an anti-infective therapeutic which serve a role in the activation of murine macrophages and provide protection against pathogens.16 Furthermore, Cordyceps sinensis has also shown to be more effective in combating bacteria and exhibits better immunomodulatory effects when used in combination with a novel anti-tuberculosis drug (PA-824) on Mycobacterium tuberculosis disease mice. The enhancement showed promising evidence in shortening the duration of tuberculosis treatment.17
Generally known as wolfberry, it is usually found in Asia particularly in the northwest region of China. The bright orange-red berry with sweet and tangy flavour is regarded as a functional food in many Asian countries.18 As a potent antioxidant, the goji berry is rich in polysaccharide and considered as one of the richest natural sources of zeaxanthin, a carotenoid that is beneficial in eye health.
The immunomodulatory effect of goji berry has also been supported by 2 human studies published in the Journal of Medicinal Food and Rejuvenation Research. Both studies demonstrated that daily consumption of goji berry-riched juice and milk-based goji berry supplement strengthen the immune responses of the healthy elderly population.19,20 Supplementation of goji berry has also shown to weaken the symptoms of influenza infection through regulation of the immune system as well as enhance the efficacy of influenza vaccination to prevent subsequent infection.21,22
Green tea is another popular ingredient widely found in East Asia and its popularity is extending to worldwide due in part to increasing awareness of the many benefits that green tea has to offer.23 Catechins are the main active compound found specifically in green tea leaves while the epigallocatechin gallate (EGCG) is the most widely studied and active form of catechin in the green tea.23
Evidence found that catechins, especially EGCG possesses anti-viral effects on influenza virus infection. A study involved 197 healthcare workers for the elderly in Japan showed that daily intake of 378mg catechins for 5 months might be effective prophylaxis for influenza infection.24 Similar finding has also been demonstrated in a study involving 2050 schoolchildren in Japan whereby the consumption of 1-5 cups of green tea daily may prevent influenza infection in elementary schoolchildren. It is believed that tea catechins bind to the hemagglutinin molecule of influenza virus thereby reduced the viral absorption as well as improve the overall systemic immunity in order to fight against viral invasion.25
A Take Home Message
Good hygiene is the first line of defence against contagious diseases. Frequent hand washing, wearing the face mask and social distancing are the crucial steps we should always keep in mind and practice accordingly, especially during the virus pandemic.
Besides, we can always do a little bit more to protect ourselves from falling sick which can be as simple as eat well, sleep well and exercise regularly.
Last but not least, stay safe and strong for yourself and your loved one.
- Sam JIC. The burden of human influenza in Malaysia. Med J Malaysia. 2015;70(3):127-130.
- Godhia ML, Patel N. Colostrum – its composition, benefits as a nutraceutical: a review. Current Research in Nutrition and Food Science. 2013;1(1):37-47.
- Bagwe S, Tharappel LJP, Kaur G, Buttar HS. Bovine colostrum: an emerging nutraceutical. Journal of Complementary and Integrative Medicine. 2015;1-11.
- Wong EB, Mallet JF, Duarte J, Matar C, Ritz BW. Bovine colostrum enhances natural killer cell activity and immune response in a mouse model of influenza infection and mediates intestinal immunity through tool-like receptors 2 and 4. Nutrition Research. 2014; 34:318-325.
- Ng WC, Wong V, Muller B, Rawlin G, Brown LE. Prevention and treatment of influenza with hyperimmune bovine colostrum antibody. PLoS ONE. 2010;5(10):1-10.
- Yan F, Polk DB. Probiotics and immune health. Curr Opin Gastroenterol. 2011;27(6):496-501.
- Berggren A, Ahren IL, Larsson N, Onning G. Randomised, double-blind and placebo-controlled study using new probiotic lactobacilli for strengthening the body immune defence against viral infections. European Journal of Nutrition. 2011;50:201-210.
- Zhang H, Yeh C, Jin Z, Ding L, Liu BY, Zhang L, et al. Prospective study of probiotic supplementation results in immune stimulation and improvement of upper respiratory infection rate. Synthetic and Systems Biotechnology. 2018;3:113-120.
- Haghani A, Mehrbod P, Safi N, Abd Kadir FA, Omar AR, Ideris A. Edible bird’s nest modulate intracellular molecular pathways of influenza A virus infected cells. BMC Complementary and Alternative Medicine. 2017;17(22):1-13.
- Helmi, Nuradji H, Dharmayanti NLPI, Mranata B, Sudarnika E, Lukman DW, et al. Antiviral activity of edible bird’s nest extract on highly pathogenic influenza H5N1 viral infection in vitro. International Journal of the Bioflux Society. 2018;10(2):62-68.
- Zhao R, Li G, Kong XJ, Huang XY, Li W, Zeng YY, et al. The improvement effects of edible bird’s nest on proliferation and activation of B lymphocyte and its antagonistic effects on immunosuppression induced by cyclophosphamide. Drug Design, Development and Therapy. 2016;10:371-381.
- Xu ML, Kim HJ, Choi YR, Kim HJ. Intake of korean red ginseng extract and saponin enhances the protection conferred by vaccination with inactivated influenza A virus. Journal of Ginseng Research. 2012;36(4):396-402.
- Yoo DG, Kim MC, Park MK, Park KM, Quan FS, Song JM, et al. Protective effect of ginseng polysaccharides on influenza viral infection. PLoS ONE. 2012; 7(3):1-8.
- Tuli HS, Sandhu SS. Pharmacological and therapeutic potential of cordyceps with special reference to cordycepin. Biotech. 2014;4(1):1-12.
- Lin BQ, Li SP. Herbal medicine: biomolecular and clinical aspects. 2nd United States: CRC Press/Taylor & Francis; 2011.
- Jordan JL, Sullivan AM, Lee TDG. Immune activation by a sterile aqueous extract of cordyceps sinensis: mechanism of action. Immunopharmacology and Immunotoxicology. 2008;30(1):53-70.
- Li DG, Ren ZX. Cordyceps sinensis promotes immune regulation and enhances bacteriostatic activity of PA-824 via IL-10 in mycobacterium tuberculosis disease. Brazillian Journal of Medical and Biological Research. 2017;50(9):1-7.
- Ma ZF, Zhang H, Teh SS, Wang CW, Zhang Y, Hayford F, et al. Goji berries as a potential natural antioxidant medicine: an insight into their molecular mechanisms of action. Oxidative Medicine and Cellular Longevity. 2019;1-9.
- Amagase H, Sun B, Nance DM. Immunomodulatory effects of a standardized lyceum barbarum fruit juice in Chinese older healthy human subjects. Journal of Medicinal Food. 2009;12(5):1159-1165.
- Vidal K, Bucheli P, Gao Q, Moulin J, Shen LS, Wang J, et al. Immunomodulatory effects of dietary supplementation with a milk-based wolfberry formulation in healthy elderly: a randomized, double-blind, placebo-controlled trial. Rejuvenation Research. 2012;15(1):89-97.
- Ren Z, Na L, Xu Y, Rozati M, Wang J, Xu J, et al. Dietary supplementation with lacto-wolfberry enhances the immune response and reduces pathogenesis to influenza infection in mice. The Journal of Nutrition. 2012;142:1596-1602.
- Du X, Wang J, Niu X, Smith D, Wu D, Meydani SN. Dietary wolfberry supplementation enhances the protective effect of flu vaccine against influenza challenges in aged mice. The Journal of Nutrition. 2014;144:224-229.
- Tran J. Green tea: a potential alternative anti-infectious agent catechins and viral infections. Advances in Anthropology. 2013;3(4):198-202.
- Matsumoto K, Yamada H, Takuma N, Niino H, Sagesaka YM. Effects of green tea catechins and theanine on preventing influenza infection among healthcare workers: a randomized controlled trial. BMC Complementary & Alternative Medicine. 2011;11(15):1-7.
- Park M, Yamada H, Matsushit K, Kaji S, Goto T, Okada Y, et al. Green tea consumption is inversely associated with the incidence of influenza infection among schoolchildren in a tea plantation area of Japan. The Journal of Nutrition. 2011;141:1862-1870.