Many of us only think about fighting off a cold once we’re already sick, but supporting the immune system before, during and after illness is the best way to reduce the frequency and severity of colds and flu.

Prevention

Boosting your immune resilience to avoid getting sick should be a top priority during cold and flu season. The following nutrients and one specific herb can help to strengthen your body’s natural immune defences.

• Vitamin C (ascorbic acid) can reduce the number of upper respiratory tract infection episodes, according to studies in children.¹
• Citrus bioflavonoids, such as quercetin, have antioxidant, anti-inflammatory, immune-modulating, and antiviral properties.²
• Vitamin A plays a critical role in maintaining barriers (e.g. the epithelial and mucosal layers of the respiratory tract) that defend against invading pathogens.³
• Vitamin D reduces the risk of acute respiratory tract infections, especially when given to those who are deficient in vitamin D.⁴
• Zinc can help to reduce the incidence of respiratory tract infections, especially in children and the elderly.⁵
• Echinacea angustifolia and E. purpurea (Echinacea) can reduce the incidence of common colds.⁶

These remedies are best combination with diet and lifestyle practices to support immune health.

Acute Symptoms

Here are some of the most common nutrients and herbs used to help effectively manage cold and flu symptoms. Combine these with adequate rest and hydration to support your body’s ability to fight off an active infection.

• Vitamin C (ascorbic acid) can reduce the duration and severity of colds.^1,5,7
• Zinc can shorten the duration of colds, especially when taken within 24 hours of the onset of symptoms.^5,8,9
• Echinacea can reduce the duration of common colds,⁶ as well as lowering the risk of recurrent respiratory infections and complications (e.g. pneumonia, otitis media/externa and tonsillitis/pharyngitis).¹⁰
• Andrographis paniculata (Andrographis) helps to alleviate symptoms of uncomplicated upper respiratory tract infections,^11,12 including cough, expectoration, nasal discharge, headache, fever, sore throat, and fatigue.¹³
• Sambucus nigra (Elderberry) can shorten the duration and lessen the severity of colds.¹⁴

Recovery

Do you feel depleted after getting through the worst of your cold or flu? Focus on recuperating – this recovery phase is known as convalescence. Sufficient rest, proper nutrition and supportive herbs can help address lingering fatigue and restore your energy levels. Consider taking:

• Ganoderma lucidum (Reishi), which is traditionally used to strengthen the body and tonify Qi (vitality and energy). It is considered a general tonic for deficiency syndromes associated with tiredness and fatigue.¹⁵
• Lentinula edodes (Shiitake), which is traditionally used for its strengthening and restorative properties.¹⁶
• Withania somnifera (Withania), which has been traditionally used in Ayurvedic medicine as a rejuvenating tonic (rasāyana).¹⁷ This herbal adaptogen is indicated for those experiencing fatigue, during convalesce and as a tonic for the elderly.^18,19
• Astragalus membranaceus (Astragalus), which is a traditional Chinese medicine used to invigorate the Spleen (helping with fatigue associated with poor appetite) and tonify Qi.^20,21

Consult a qualified healthcare practitioner for personalised advice before using any supplements, especially if you are pregnant, breastfeeding, administering to children, taking medication, or have a diagnosed medical condition.

References

1. Saeed H, Abdelrahim MEA. A meta-analysis of the effectiveness of vitamin C in the prevention and treatment of childhood upper respiratory tract infections. J Clin Nurs Res. 2023;7(1):30-37. DOI: 10.26689/jcnr.v7i1.4403

2. Gasmi A, Mujawdiya PK, Lysiuk R, Shanaida M, Peana M, Gasmi Benahmed A, et al. Quercetin in the prevention and treatment of coronavirus infections: a focus on SARS-CoV-2. Pharmaceuticals (Basel). 2022 Aug;15(9):1049. DOI: 10.3390/ph15091049

3. Huang Z, Liu Y, Qi G, Brand D, Zheng SG. Role of vitamin A in the immune system. J Clin Med. 2018 Sep;7(9):258. DOI: 10.3390/jcm7090258

4. Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P, et al. Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ. 2017 Feb;356:i6583. DOI: 10.1136/bmj.i6583

5. Rondanelli M, Miccono A, Lamburghini S, Avanzato I, Riva A, Allegrini P, et al. Self-care for common colds: the pivotal role of vitamin D, vitamin C, zinc, and echinacea in three main immune interactive clusters (physical barriers, innate and adaptive immunity) involved during an episode of common colds-practical advice on dosages and on the time to take these nutrients/botanicals in order to prevent or treat common colds. Evid Based Complement Alternat Med. 2018;2018:5813095. DOI: 10.1155/2018/5813095

6. Shah SA, Sander S, White CM, Rinaldi M, Coleman CI. Evaluation of echinacea for the prevention and treatment of the common cold: a meta-analysis. Lancet Infect Dis. 2007 Jul;7(7):473-480. DOI: 10.1016/S1473-3099(07)70160-3

7. Hemilä H, Chalker E. Vitamin C reduces the severity of common colds: a meta-analysis. BMC Public Health. 2023 Dec;23(1):2468. DOI: 10.1186/s12889-023-17229-8

8. Hemilä H, Petrus EJ, Fitzgerald JT, Prasad A. Zinc acetate lozenges for treating the common cold: an individual patient data meta-analysis. Br J Clin Pharmacol. 2016 Nov;82(5):1393-1398. DOI: 10.1111/bcp.13057

9. Hemilä H, Chalker E. The effectiveness of high dose zinc acetate lozenges on various common cold symptoms: a meta-analysis. BMC Fam Pract. 2015 Feb;16:24. DOI: 10.1186/s12875-015-0237-6

10. Schapowal A, Klein P, Johnston SL. Echinacea reduces the risk of recurrent respiratory tract infections and complications: a meta-analysis of randomized controlled trials. Adv Ther. 2015 Mar;32(3):187-200. DOI: 10.1007/s12325-015-0194-4

11. Coon JT, Ernst E. Andrographis paniculata in the treatment of upper respiratory tract infections: a systematic review of safety and efficacy. Planta Med. 2004 Apr;70(4):293-298. DOI: 10.1055/s-2004-818938

12. Poolsup N, Suthisisang C, Prathanturarug S, Asawamekin A, Chanchareon U. Andrographis paniculata in the symptomatic treatment of uncomplicated upper respiratory tract infection: systematic review of randomized controlled trials. J Clin Pharm Ther. 2004 Feb;29(1):37-45. DOI: 10.1046/j.1365-2710.2003.00534.x

13. Saxena RC, Singh R, Kumar P, Yadav SC, Negi MP, Saxena VS, et al. A randomized double blind placebo controlled clinical evaluation of extract of Andrographis paniculata (KalmCold) in patients with uncomplicated upper respiratory tract infection. Phytomedicine. 2010 Mar;17(3-4):178-185. DOI: 10.1016/j.phymed.2009.12.001

14. 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 Mar;8(4):182. DOI: 10.3390/nu8040182

15. American Herbal Pharmacopoeia. Reishi mushroom - Ganoderma lucidum: standards of analysis, quality control, and therapeutics. Santa Cruz: American Herbal Pharmacopoeia; 2000.

16. Hobbs C. Medicinal mushrooms: an exploration of tradition, healing, & culture. Summertown; Botanica Press; 1995.

17. Singh N, Bhalla M, De Jager P, Gilca M. An overview on ashwagandha: a rasayana (rejuvenator) of Ayurveda. Afr J Tradit Complement Altern Med. 2011;8(5 Suppl):208-213. DOI: 10.4314/ajtcam.v8i5S.9

18. Thomsen M. Phytotherapy desk reference. 5th ed. 2020.

19. Bone K. The ultimate herbal compendium: a desktop guide for herbal prescribers. Warwick: Phytotherapy Press; 2007.

20. Zheng Y, Ren W, Zhang L, Zhang Y, Liu D, Liu Y. A review of the pharmacological action of astragalus polysaccharide. Front Pharmacol. 2020;11:349. DOI: 10.3389/fphar.2020.00349

21. Bone K, Mills S. Principles and practice of phytotherapy: modern herbal medicine. 2nd ed. London: Churchill Livingstone; 2013.