Reishi Mushroom for the Immune System

It’s likely no surprise that we’re well in the midst of cold and flu season. However, with how things have been going for the last couple of years, you’re probably wondering “when is cold and flu season now anyways?” You’re likely surrounded by friends, family, even co-workers who have been affected and it seems inevitable that you’ll wake up with flu-like symptoms one day, too.

While we’re washing our hands and always trying our best to prevent any unwelcome visitors past our immune defences, immune support should be an essential part of our lives year-round and could be the difference between spending this season in bed or out enjoying the crisp winter air. Before you stock up on cold and flu medications prematurely, let’s discuss medicinal mushrooms and how they’ve been used as foods that boost immune system health for centuries! 

reishi mushroom fruiting body

Using Reishi Mushroom during Cold and Flu Season

Ganoderma lucidum, commonly known as Reishi, has been used for centuries in Eastern medicine to prevent and treat various human conditions. Reishi has been found to promote innate immune function, humoral immunity, and cellular immunity, meaning it can prevent against foreign pathogens entering our bodies, while also improving our defense against pathogens that have previously gotten past our defences [1]. Reishi mushroom benefits are endless, but we’ll focus on how exactly these interesting fungi may prove to be useful this cold and flu season! 

Reishi contains two constituents which may greatly benefit the immune system; the b-D-glucans (polysaccharides) are immunomodulatory, while the triterpenoids have strong anti-viral properties [2]. 

Macrophages are specialized cells in our bodies involved in the detection and destruction of bacteria and other harmful organisms. These immune cells, along with many others, carry specific receptors for b-D-glucans, such as dectin-1 and TLR-2 [3]. Dectin-1 is the most abundant receptor, and its activation stimulates processes that lead to the death and elimination of pathogenic microorganisms that may invade the body [3]. TLRs (toll-like receptors) are another common receptor of the immune system involved in the early stages of infection as they initiate the innate immune response. When b-D-glucans bind to TLRs, this can activate the innate immune system and induce the production of important cytokines crucial in controlling the growth and activity of other immune cells [3]. The ability of b-D-glucans to interact with these immune cells is significant as it illustrates the capacity in which Reishi can target bacteria, viruses, even cancer cells.  

There is some convincing evidence that Reishi may be useful in the treatment of COVID-19 [4]. One study found that the b-D-glucans in Reishi increased lymphocytes and boosted PRRs signals [4]. Lymphocytes are white blood cells that help our bodies fight infections, while PRRs are pathogen recognition receptors that play a crucial role in our first-line immune defense as their activation is needed to initiate the innate immunity cascade. Thus, the study suggests that the protective inflammatory responses that are developed prevent infections by pathogens, including infection by COVID-19 [4].  

Researchers have identified over 100 different triterpenes in Reishi (50 of which are not found in any other mushroom). Other terpenoids in Reishi have exhibited antioxidative and antiviral activities as well [5]. The triterpenoids present in Reishi illustrated inhibition of early-stage coronavirus 229E infection by impairing virus replication, absorption, and penetration in one study [4]. In fact, another study suggested that Reishi may be a good candidate for the development of various antiviral agents as it has the potential to fight against herpes, EBV, VSV, hepatitis, and even the H1N1 strain of the flu [4].  

Neuraminidase (NA) inhibitors are one of the dominant anti-viral pharmaceuticals used for treating the influenza virus [6]. However, new NA inhibitors are constantly being researched because of the increasing prevalence of drug resistance. Reishi has established itself as a topic of research in this area because of its triterpenoid constituents. One study found that two types of ganoderic acid acted as NA inhibitors against the H5N1 and H1N1 strains of influenza [6]. The study believes that the triterpenoid structure is a potential scaffold for the design of new NA inhibitors as drug resistance to current ones continues to increase [6].  

Adding Reishi to your Daytime or Nighttime Routine

Adding a Reishi mushroom supplement into your daily routine may be a beneficial step to take in supporting your immune health. However, don’t forget that health starts at the foundations; ensure you’re getting enough restful sleep, eating nourishing foods, hydrating, and participating in heartrate-increasing movement every day. Most importantly, don’t forget to take care of yourself, both mentally and physically. Stay safe and healthy! 

We hope you have found this article informative. If you have any questions or comments, please feel free to leave them in the comment section below! 

By Silvana Jakupovic — BSc and 4th Year Student of Naturopathic Medicine (CCNM-Boucher) 


[1] Wang X, Lin Z. Immunomodulating Effect of Ganoderma (Lingzhi) and Possible Mechanism. Adv Exp Med Biol. 2019;1182:1-37. doi: 10.1007/978-981-32-9421-9_1. PMID: 31777013. 

[2] Ahmad MF, Ahmad FA, Khan MI, Alsayegh AA, Wahab S, Alam MI, Ahmed F. Ganoderma lucidum: A potential source to surmount viral infections through β-glucans immunomodulatory and triterpenoids antiviral properties. Int J Biol Macromol. 2021 Sep 30;187:769-779. doi: 10.1016/j.ijbiomac.2021.06.122. Epub 2021 Jun 29. PMID: 34197853. 

[3] Mirończuk-Chodakowska I, Kujawowicz K, Witkowska AM. Beta-Glucans from Fungi: Biological and Health-Promoting Potential in the COVID-19 Pandemic Era. Nutrients. 2021 Nov 6;13(11):3960. doi: 10.3390/nu13113960. PMID: 34836215; PMCID: PMC8623785. 

[4] Cör Andrejč D, Knez Ž, Knez Marevci M. Antioxidant, antibacterial, antitumor, antifungal, antiviral, anti-inflammatory, and nevro-protective activity of Ganoderma lucidum: An overview. Front Pharmacol. 2022 Jul 22;13:934982. doi: 10.3389/fphar.2022.934982. PMID: 35935849; PMCID: PMC9353308. 

[5] Dasgupta A, Acharya K. Mushrooms: an emerging resource for therapeutic terpenoids. 3 Biotech. 2019 Oct;9(10):369. doi: 10.1007/s13205-019-1906-2. Epub 2019 Sep 24. PMID: 31588393; PMCID: PMC6760460. 

[6] Zhu Q, Bang TH, Ohnuki K, Sawai T, Sawai K, Shimizu K. Inhibition of neuraminidase by Ganoderma triterpenoids and implications for neuraminidase inhibitor design. Sci Rep. 2015 Aug 26;5:13194. doi: 10.1038/srep13194. PMID: 26307417; PMCID: PMC4549708.  

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