Herbs to Support the Immune System

Naturopathic medicine offers a myriad of ways to support our bodies during times of illness. An important tenet of naturopathic medicine is focusing on prevention, and one way to accomplish this is by supporting our immune systems to help ward off infections. Yet if we do become ill, natural therapies can still be incredibly helpful, and there is mounting evidence supporting the use of naturopathic modalities, such as herbs, in the setting of infectious disease.

Astragalus

Astragalus root is considered an herbal adaptogen, meaning it helps your body respond to stress in a healthy way. As an herb that regulates the immune system, it may protect against certain viral illnesses if taken before the onset of symptoms.1-5 Of note, astragalus has been shown in human studies to modulate the Th1/Th2 immune response in the setting of viral illnesses.1 

One study found that Echinacea, Astragalus, and Glycyrrhiza (licorice) all stimulated activation of CD4 and CD8 T cells in human subjects within 24 hours after ingestion, with continued activation for 7 days.2 Furthermore, astragalus has been shown to exhibit some antiviral effects in addition to its immunoregulatory activity.5

A delicious way to enjoy the health benefits of astragalus (and other warming, immune-supporting herbs) is to make a cup of astragalus chai: https://learningherbs.com/remedies-recipes/astragalus-chai/.

Glycyrrhiza glabra (Licorice)

Like astragalus, licorice root falls under the adaptogenic herbs category. A poor response to stress can significantly impact the immune system and its ability to ward off disease.6 Additionally, in vitro studies have concluded that licorice displays antiviral activity against a number of different viruses, including RSV,7-8 HIV-1,7,9 HSV,9 and SARS-related coronavirus.7,10

As a soothing demulcent herb, licorice can also be beneficial for alleviating sore throats and dry coughs.11 It has a sweet, distinctive taste that goes well with other herbs and eliminates the need for added sugar in herbal formulas. Try pairing licorice root with marshmallow root and rose petals for a delicious, throat-soothing tea.

A word of caution: Licorice is contraindicated in people with high blood pressure, as prolonged use of licorice may increase blood pressure and lead to hypokalemia.12

Melissa officinalis (Lemon balm)

Lemon balm gets its name from the bright, lemony scent of its medicinal leaves. It has shown promise for exhibiting antiviral activity, most notably against herpes simplex virus13-14 and enteroviruses.15 Studies have also demonstrated that lemon balm is immunomodulating,16 allowing for a more robust and healthier immune system.

Lemon balm is also incredibly helpful for nervousness and anxiety,17 which can contribute to stress and further deplete your immune system.

Lemon balm makes a great tea with a lemon aroma that you can drink frequently throughout the day.

For those who don’t have access to herbs like Astragalus and Licorice, the following medicinal herbs are ones that you’ll likely be able to find in your kitchen pantry:

Cinnamon

Cinnamon is a common kitchen spice that has been studied for its effects on certain viruses, including influenza. It may be able to inhibit certain viral infections as well as reduce the duration of symptoms.18,19

Cinnamon combines well with ginger, lemon, and honey to make a warming and immune-supportive tea.

Garlic

There are a growing number of studies indicating that garlic possesses immunomodulatory and antiviral capabilities.20-22 One trial revealed that participants who took a garlic supplement (containing 180mg of allicin) had a significantly reduced occurrence of the common cold as compared to placebo, as well as fewer days of illness for those in the garlic group who did get sick.20

As a pungent herb, it stimulates circulation and warms the body. While there are garlic supplements available, it is much preferred to eat the garlic in food form. Crush or chop the garlic and then allow it to sit at room temperature for about 10 minutes to optimize its health benefits before adding it to your meal.  

Rosemary

Rosemary is a member of the mint family, along with thyme, oregano, sage, and lemon balm. It is a pungent, aromatic herb that promotes circulation, warming up the lungs and easing congestion. Several studies have shown that different extracts of rosemary exhibit antiviral and immunomodulatory effects.23-25

Add rosemary to a steam inhalation to clear out nasal passageways and relieve dry respiratory mucosa.

Disclaimer: This is for educational purposes only. Please seek medical attention from a healthcare practitioner if you are experiencing signs of illness. Note that the above information is not intended as a substitute for medical care nor does it infer that these herbs treat, cure, or prevent any disease.

References:

1. Mao SP, Cheng KL, Zhou YF. Modulatory effect of Astragalus membranaceous on Th1/Th2 cytokine in patients with herpes simplex keratitis. Chinese Journal of Traditional Chinese Medicine. 2004 Feb; 24(2): 121-3.
2. Brush J, Mendenhall E, Guggenheim A, Chan T, Connelly E, Soumyanath A, Buresh F, Barrett R, Zwickey H. The effect of Echinacea purpurea, Astragalus membranaceus and Glycyrrhiza labra on CD69 expression and immune cell activation in humans. Phytother Res. 2006 Aug; 20(8): 687-95.
3. Kajimura K, Takagi Y, Ueba N, Yamasaki K, Sakagami Y, Yokoyama H, Yoneda K. Protective effect of astragali radix by oral administration against Japanese encephalitis virus infection in mice. Bio Pharm Bull. 1996 Sep; 19(9): 1166-9.
4. Shao BM, Xu W, Dai H, Tu P, Li Z, Gao XM. A study on the immune receptors for polysaccharides from the roots of Astragalus membranaceus, a Chinese medicinal herb. Biochem Biophys Res Commun. 2004 Aug 6; 320(4): 1103-11.
5. Li X, Qu L, Dong Y, Han L, Liu E, Fang S, Zhang Y, Wang T. A review of recent research progress on the astragalus genus. Molecules. 2014 Nov 17; 19(11): 18850-80.
6. Morey JN, Boggero IA, Scott, AB, Segerstrom SC. Current Directions in Stress and Human Immune Function. Curr Opin Psychol. 2015 Oct 1; 5: 13-17.
7. Fiore C, Eisenhut M, Krausse R, Ragazzi E, Pellati D, Armanini D, Bielenberg J. Antiviral effects of Glycyrrhiza species. Phytother Res. 2008 Feb; 22(2): 141-8.
8. Feng Yeh C, Wang KC, Chiang LC, Shieh DE, Yen MH, San Chang J. Water extract of licorice had anti-viral activity against human respiratory syncytial virus in human respiratory tract cell lines. J Ethnopharmacol. 2013 Jul 9; 148(2): 466-73.
9. Fukuchi K, Okudaira N, Adachi K, Odai-Ide R, Watanabe S, Ohno H, Yamamoto M, Kanamoto T, Terakubo S, Nakashima H, Uesawa Y, Kagaya H, Sakagami H. Antiviral and Antitumor Activity of Licorice Root Extracts. In Vivo. 2016 11-12; 30(6): 777-785.
10. Cinati J, Morgenstern B, Bauer G, Chandra P, Rabenau H, Doerr HW. Glycyrrhizin, an active component of liquorice roots, and replication of SARS-associated coronavirus. Lancet. 
11. Honarmand A, Safavi M, Safaei Arana A, Shokrani O. The efficacy of different doses of liquorice gargling for attenuating postoperative sore throat and cough after tracheal intubation. Eur J Anaethesiol. 2016 Aug; 33(8): 595-6.
12. Farese RV Jr, Biglieri EG, Shackleton CH, Irony I, Gomez-Fontes R. Licorice-induced hypermineralocorticoidism. N Engl J Med. 1991 Oct 24; 325(17): 1223-7.
13. Nolkemper S, Reichling J, Stintzing FC, Carle R, Schnitzler P. Antiviral effect of aqueous extracts from species of the Lamiaceae family against Herpes simplex virus type 1 and type 2 in vitro. Planta Med. 2006 Dec; 72(15): 1378-82.
14. Astana A, Navid MH, Schnitzler P. Attachment and penetration of acyclovir-resistant herpes simplex virus are inhibited by Melissa officinalis extract. Phytotherapy Res. 2014 Oct; 28(10): 1547-52.
15. Chen S, Leu Y, Cheng M, Ting SC, Liu C, Wang S, Yang C, Hung C, Sakurai H, Chen K, Ho H. Anti-enterovirus 71 activities of Melissa officinalis extract and its biologically active constituent rosmarinic acid. Sci Rep. 2017; 7: 12264.
16. Drozd J, Anuszewska E. The effect of the Melissa officinalis extract on immune response in mice. Acta Pol Pharm. 2003 Nov-Dec; 60(6): 467-70.
17. Scholey A, Gibbs A, Neale C, Perry N, Ossoukhova A, Bilog V, Kras M, Scholz C, Sass M, Buchwald-Werner S. Anti-Stress Effects of Lemon Balm-Containing Foods. Nutrients. 2014 Nov; 6(11): 4805-4821.
18. Nabeshima S, Kashiwagi K, Ajisaka K, Masui S, Takeoka H, Ikematsu H, Kashiwagi S. A randomized, controlled trial comparing traditional herbal medicine and neuraminidase inhibitors in the treatment of seasonal influenza. J Infect Chemother. 2012 Aug; 18(4): 534-43.
19. Zhuang M, Jiang H, Suzuki Y, Li X, Xiao P, Tanaka T, Ling H, Yang B, Saitoh H, Zhang L, Qin C, Sugamura K, Hattori T. Procyanidins and butanol extract of Cinnamomi Cortex inhibit SARS-CoV infection. Antiviral Res. 2009 Apr; 82(1): 73-81.
20. Bayan L, Koulivand PH, Gorji A. Garlic: a review of potential therapeutic effects. Avicenna J Phytomed. 2014 Jan-Feb; 4(1): 1-14.
21. Shojai TM, Langeroudi AG, Karimi V, Barin A, Sadri N. The effect of Allium sativum (Garlic) extract on infectious bronchitis in specific pathogen free embryonic egg. Avicenna J Phytomed. 2016 Jul-Aug; 6(4): 458-267.
22. Moutia M, Habti N, Badou A. In Vitro and In Vivo Immunomodulator Activities of Allium sativum L. Evid Based Complement Alternat Med. 2018; 2018: 4984659.
23. Shin H, Choi M, Ryu B, Lee N, Kim H, Choi H, Chang J, Lee K, Jang DS, Inn K. Antiviral activity of carnosic acid against respiratory syncytial virus. Virol J. 2013; 10: 303.
24. Tsai T, Chuang L, Lien T, Liing Y, Chen W, Tsai P. Rosmarinus officinalis Extract Suppresses Propionibacterium acnes-Induced Inflammatory Responses. J Med Food. 2013 Apr; 16(4): 324-333.
25. Lin W, Yu Y, Jinn T. Evaluation of the virucidal effects of rosmarinic acid against enterovirus 71 infection via in vitro and in vivo study. Virol J. 2019; 16: 94.