The reishi mushroom, also known as lingzhi, is fast gaining popularity for its amazing health benefits. It has already been widely used in Traditional Chinese Medicine, for centuries, to restore overall balance and to empower the body to fight stress and disease. Since the woody mushroom is believed to improve overall health and longevity, it is also known as the “Mushroom of Immortality”.
Studies show that reishi mushroom is loaded with over 400 bioactive compounds, including triterpenoids, polysaccharides, sterols, steroids, fatty acids and proteins. These compounds are responsible for a number of healing and enhancing effects because of their anti-microbial, anti-tumor, antiaging, antioxidant, anti-inflammatory, anti-diabetic, liver-protective, anti-fungal, anti-viral and immune balancing properties, as reported by a 2018 review. 
This review also reports that “It has been used for the prevention as well as the treatment of various diseases, such as chronic hepatitis, nephritis, high blood pressure, bronchitis and tumorigenic afflictions since ancient time and is a super immune stimulant, which strongly protects the entire body. “
So, how does Reishi support your immune system? Research shows that this woody mushroom has a balancing effect on the immune system; meaning it activates immune components that are needed to fight microbial attacks and inflammation, and at the same time keep a check on immune responses that cause allergies and autoimmune disorders.
Reishi Mushroom in Immunity
A healthy immune system protects you from infection and disease caused by bacteria, virus, fungi and parasites. Your immune system, if working well, even has the power to fight cancer cells. It launches inflammatory responses to destroy pathogens and is also crucial in turning off this response once the trigger has been eliminated. Unchecked, long term inflammation makes you age faster on a cellular level and is believed to be the underlying cause of most chronic ailments such as arthritis, cardiovascular disease, type 2 diabetes, cataracts, neurodegeneration and cancer.
While you want your immune system to be active and responding well to outside triggers in a timely manner, you don’t want it to be “too active”.
A sluggish immune system that is not very efficient at responding to the attack by foreign invaders makes your body vulnerable to infections like cold, flu and other diseases. On the other hand, an over responding immune system can give rise to challenging health issues such as asthma, allergies and autoimmune disorders. A hyperactive immune system can’t differentiate between the body’s own healthy cells (self) and unhealthy cells that invades the body (non-self). As a result, it unleashes unwanted immune and inflammatory responses against self, leading to allergies and autoimmune disorders.
The secret to Reishi mushroom’s benefits in immunity lies in the bioactive compounds it contains. These compounds work through their own unique mechanisms in either activating or suppressing different components of the immune system – thus upregulating or downregulating immune functions.
In addition, synthetic antibiotics, antiviral and anti-allergic drugs have undesirable side effects. The emergence of antibiotic resistant bacteria has complicated the treatment scenario even further. This makes natural agents like reishi mushroom with its anti-viral, anti-fungal, anti-bacterial and anti-allergic properties an exciting possibility for achieving a well-balanced and healthy body.
1. Fights allergies
Reishi mushroom has been found to be immensely helpful in reducing allergies and improving symptoms in asthma, bronchitis, rheumatism and contact dermatitis.
As discussed earlier, reishi mushroom contains many bioactive compounds. Out of these, triterpenes and polysaccharides in reishi are mainly responsible for its anti-allergic and anti-inflammatory properties. Triterpenes supress the release of histamine, a chemical released during allergic responses. It is histamine that gives allergic symptoms like runny nose, itching, hives, watery eyes and bronchial constriction. Antioxidant content in the mushroom helps curb inflammation while germanium improves oxygen flow to the tissues, required in allergic responses.
Allergies occur due to an overactive immune response. Most herbs have a boosting effect on the immune system, which could actually worsen allergy symptoms. Reishi, however, has a balancing effect, and this is the reason why reishi can be so good at giving weak immunity a boost while also lowering undesirable immune responses that result in allergies.
2. Boosts the immune system
The function of your immune system deteriorates with age. This is called immunosenescence. The ability of immune cells to respond to foreign substances reduces with age, increasing the risk of developing opportunistic infections such as influenza and pneumonia.
Polysaccharides, triterpenes and germanium are the main ingredients in reishi mushroom that reinforce the immune system. Reishi mushroom enhances the activity of immune cells that help fight cancer and infections caused by bacteria and viruses. The polysaccharides in reishi mushroom influence the production and activity of various immune cells including B cells, T cells, dendritic cells, natural killer cells and macrophages.
All these cells help the immune system to effectively target bacterial and viral intruders, getting rid of them faster. Reishi mushroom can be particularly effective in improving the immune functions in elderly people, and people with a compromised immune system.
- B cells are highly specialized immune cells that make antibodies to fight and destroy foreign cells. B cells bind to foreign antigens (proteins present on bacteria and viruses) and trigger the immune system to make antibodies to deal with these antigens.
- There are two types of T cells; helper T cells that help B cells to make antibodies and natural killer cells that specialize in identifying and directly destroying virus infected cells. These killer cells can even kill cancer cells. In fact, NK cells also protect against mycobacterial infections, for example tuberculosis. . Helper T cells also help in activating NK cells.
- Dendritic cells stimulate T cells into action and help these immune cells to identify and destroy foreign invaders. These immune cells also promote tolerance to self-antigens (proteins and sugars present on body’s own healthy cells). All these functions help in regulating immunity.
- Macrophages are large immune cells that consume bacteria and other foreign cells. Macrophages also help T cells identify pathogens.
Improves the antibacterial activity of antibiotics
In a 2012 study, researchers found that reishi mushroom has the potential to improve the efficiency of antibiotics. When used along with antibiotics, reishi enhances their antibacterial function and inhibits the growth of harmful bacteria. 
The extracts made of reishi mushroom are not only rich in immune boosting bioactive compounds but also contain trace minerals - zinc and selenium. These minerals are extremely important in preventing viral infections and reducing their severity.
How does Reishi work as an anti-viral agent? Various compounds and trace minerals in the mushroom increase the production of interferons, substances that help prevent viral replication. Interferons, as signalling molecules, also activate other immune cells such as natural killer cells and macrophages. This effect on all kinds of immune cells eventually helps in maintaining a strong immune system that is pro-active in dealing with any viral attack. However, the antiviral effects of reishi have been found to be more remarkable if given before the viral outbreak.
Reishi mushroom has been shown to be helpful in:
- Inhibiting influenza, the viral infection also known as ‘flu’
- Inhibiting infection and symptoms caused by Herpes simplex, a virus responsible for causing cold sores and genital herpes
- Inhibiting infection caused by Herpes zoster, known to cause shingles.
- Reducing the painful effects ‘Postherpetic Neuralgia’, a painful complication associated with shingles. It causes burning pain that persists even after the blisters are gone. It is challenging to manage through conventional treatments, as this condition often develops resistance.
- Inhibiting Epstein-Barr virus (EBV) that causes mononucleosis in teenagers. Mononucleosis is an infectious illness with symptoms such as fever, rash and swollen glands. EBV is also strongly implicated in aggressive lymphomas (cancer of lymph nodes) in adults.
- Protecting the liver against the damaging effects of Hepatitis B virus
In this study, Ganoderma lucidum was tested for its antifungal activity against Candida, a type of yeast that can cause fungal infections, and other important fungi. Candida can cause vaginal yeast infection or oral thrush where infection develops in the mouth.
The study found that Ganoderma lucidum extracts “had high inhibitory action” against the fungi included in the study but provided the maximum protection against Candida. This is an important finding as most synthetic antimicrobials have side effects whereas ones made from plants are not only effective in treating microbial infections but also lessen unwanted side effects. 
Enhances the activity of immune cells that help fight cancer
In Japan, reishi mushroom is used as an adjunct to cancer treatment and also to minimize the side-effects of chemotherapy. There are multiple ways reishi targets and destroys cancer cells in humans, and its ability to stimulate the immune system is one of the main mechanisms here. In addition, dominating bioactive compounds in reishi (polysaccharides, triterpenes and peptides) work as antioxidants and help in lowering inflammation, increasing the levels of antioxidant enzymes and protects DNA from oxidative damage.
This study shows that reishi mushroom activates natural killer cells.  NK cells specialize in identifying and destroying cancerous cells before they can take root. In addition, polysaccharides in reishi mushroom can destroy fibrinogen, which is a protein coating that hides cancer cells from the circulating immune cells. Once this coating is broken down, natural killer cells can easily identify and destroy cancer cells. 
There is no doubt that we need more large-scale studies that can confirm the use of reishi mushroom supplements as a primary mode of cancer treatment, but many studies have already demonstrated that it can be safely and effectively used as an adjunct to chemotherapy and radiotherapy. It improves the anti-tumor activity of these traditional treatments and boosts immunity. 
Reishi mushroom also lessens the severity of common sides effects caused by chemotherapy, such as loss of appetite, impaired immunity and hair loss. In addition, there is evidence that polysaccharides present in Reishi can stimulate the repair of DNA strand breaks in human cells. This is useful in protecting against radiation exposure. 
Using reishi mushroom along with chemotherapy can help improve quality of life in cancer patients, which is not only marred by cancer itself but also by the side effects experienced during its treatment.
How else does Reishi mushroom empower your immunity?
Reishi is a powerful adaptogen, categories of herbs that are famous for their ability to maintain and restore overall balance in the body. One of the main features of adaptogenic plants are that they can regulate the body’s function according to the requirement. This is also how reishi maintains a healthy immune system that work both ways.
Adaptogens make the body better in adapting to stress, which can come from any source. If you think stress is all about emotional distress around taking care of a sick child, an upcoming promotion or meeting tight deadlines at work, you are wrong. Lack of sleep, dealing with stubborn infections, exposure to extreme temperature, surgery, toxin exposure and unhealthy diet can all stress your body.
Long-term stress can cause hormonal imbalances and inflammation and also increases your risk of heart disease, obesity, depression and cancer. Stress also has an undesirable effect on your immunity and increases your risk of infections and diseases. While it may not be possible to be completely “stress-free”, additional support that can help you manage all this stress and remain healthy while also building a strong immunity is extremely useful.
Polysaccharides and triterpenes in reishi help the body adapt to stress better. And as an adaptogen, it improves the functions of many body systems, including the immune system, nervous system and endocrine system. Normal functioning of these major systems is crucial in dealing with stress and also in improving energy levels and reducing fatigue.
A small study found that reishi can help alleviate many symptoms associated with neurasthenia, a condition marked by excessive physical and mental fatigue. The study concluded that polysaccharide extract of reishi mushroom is “significantly superior to placebo with respect to the clinical improvement of symptoms in neurasthenia.” 
In addition to supporting immune functions, reishi can also improve energy levels, improve liver functions, protect the liver from damage, balance hormones and lower blood pressure. As an antioxidant and anti-inflammatory, it also protects heart health and lowers the risk of heart disease. The really great thing is that reishi mushrooms can improve so many health parameters without causing any significant side effects.
With winter approaching, using reishi mushroom supplements may be a good idea to give your immune system a much-needed boost. It may not only help you ward off viral and bacterial infections but reduce the risk of allergies in people who are prone.
“It is advisable to consult your healthcare practitioner before taking any supplement as they may interfere with any existing health condition, or any medication you are currently taking. But always weigh up the advantages, and pros and cons for yourself. Do your own research and never rely solely on what others tell you. Even your doctor does not know everything."
- Cör et al. Antitumour, Antimicrobial, Antioxidant and Antiacetylcholinesterase Effect of Ganoderma Lucidum Terpenoids and Polysaccharides: A Review. 2018.
- Lu et al. NK cells kill mycobacteria directly by releasing perforin and granulysin. J Leukoc Biol. 2014
- Gao et al. Effects of ganopoly (a Ganoderma lucidum polysaccharide extract) on the immune functions in advanced-stage cancer patients. Immunol Invest. 2003
- Karwa et al. Naturally occurring medicinal mushroom-derived antimicrobials: a case-study using Lingzhi or Reishi Ganoderma lucidum (W. Curt.:Fr.) P. Karst. (higher Basidiomycetes). Int J Med Mushrooms. 2012
- Naveenkumar et al. Screening of Antifungal Activity of Ganoderma Lucidum extract Against Medically Important Fungi. Indian Journal of Public Health Research & Development. 2018
- Chang et al. Ganoderma lucidum stimulates NK cell cytotoxicity by inducing NKG2D/NCR activation and secretion of perforin and granulysin. Innate Immun. 2014
- Zheng et al. Ganoderma lucidum polysaccharides eradicates the blocking effect of fibrinogen on NK cytotoxicity against melanoma cells. Oncol Lett. 2012 Mar;3(3):613-6.
- XingZhing et al. Ganoderma lucidum (Reishi mushroom) for cancer treatment. The Cochrane Database of Systematic Reviews. 2016
- Pillai et al. Enhancement of repair of radiation induced DNA strand breaks in human cells by Ganoderma mushroom polysaccharides. Food Chemistry. 2010.
- Tang et al. A randomized, double-blind and placebo-controlled study of a Ganoderma lucidum polysaccharide extract in neurasthenia. J Med Food. 2005