Medicinal mushrooms are fungi that have played an essential role in traditional Oriental Medicine systems for thousands of years, and over 100 species are found in modern Chinese medicine.
Of the myriad of health benefits that western science is just now getting caught up on, mushrooms offer surprising immune system-boosting properties that make them a promising supplemental avenue of prevention and treatment for a wide variety of diseases such as cancer, HIV, and more.
We will take a look at the top mushrooms for immune support backed by the most recent scientific studies, as well as how you would go about taking these immune-supporting fungi to maximize their benefits.
How do Mushrooms Boost the Immune System?
Mushrooms in general stimulate, strengthen, and modulate the immune system. While mushrooms contain a wide variety of bioactive constituents such as proteins, nucleotides, terpenoids, and polysaccharide peptides, the biologically active polysaccharides of many different chemical compositions are of particular interest for their immune stimulating and modulating effects.
The majority of these polysaccharides belong to the group of B-glucans. B glucans are natural components of the fungi cell wall and are mostly medically associated with stimulating cells in the innate immune system, but also have been purported to have anti-carcinogenic, antioxidant, cardioprotective, antiviral, antibacterial, hepatoprotective, and detoxifying effects.
A Quick Overview of the Immune System
It is well-established that mushrooms are adept at immune modulation and affect a variety of key players of the immune system, including hematopoietic stem cells, lymphocytes, macrophages, T cells, dendritic cells (DCs), and natural killer (NK) cells. While the known mechanisms behind the immune system are incredibly complex and interconnected, this section will be a basic rundown of the major components of the immune system that are influenced by mushroom bioactive compounds.
The immune system can be broken down into the innate immune system and the adaptive immune system. Innate immunity refers to the immediate, non-specific immune response against pathogens, including physical, chemical, and cellular defenses. Adaptive immunity is the long-term, specific immune response created by the exposure to a foreign substance. It is mediated by T and B lymphocytes and when gone awry, results in autoimmune diseases.
A hematopoietic stem cell is a type of immature blood cells that can develop into other cells, such as white blood cells, red blood cells, or platelets.
Lymphocytes are found in lymph throughout the body and are the white blood cells. The three major types of lymphocytes include B cells, T cells, and NK cells.
Macrophages are the scavengers of the immune system, they are a type of white blood cell that engulfs cellular debris, cancer cells, microbes, and other foreign substances.
T cells are a type of lymphocyte crucial to the adaptive immune response by searching out and destroying foreign invaders. T-cells can be divided into two basic types: Helper T-cells and cytotoxic T-cells. Helper T-cells activate cytotoxic T-cells and macrophages to attack infected cells or stimulate the B-cells to secrete antibodies. Cytotoxic T-cells directly kill cells by recognizing specific antigens on the cell surface of those that are infected, damaged or cancerous. These cells also secrete cytokines, such as interleukins, which are signaling proteins which mount a full immune response by stimulating or inhibiting the response of other immune cells.
Dendritic cells initiate the adaptive immune response by processing antigens, or specific proteins that “label” the invaders, and present it on the cell surface to the T cells of the immune system.
The Anti-Cancer Properties of Medicinal Mushrooms
Several medicinal mushrooms, which will be discussed below, are implicated in slowing the growth of tumors, regulating tumor genes, decreasing tumor angioneogenesis, and increasing malignant-cell phagocytosis. The stimulating effects on NK cells, macrophages, and T cells make them attractive options as adjunct therapies to chemotherapy, either to enhance the therapy’s effectiveness or mitigate the negative effects of the therapy, namely myelosuppression.
These cells additionally stimulate the production of cytokines, which are key mediators of the full immune response. The anti-cancer properties are mostly brought about from the stimulation of Th-1 cytokines, notably interferon gamma, which is involved in the production of tumor-specific antigens.
The Top Mushrooms for Boosting the Immune System
Turkey tail is packed with free-radical fighting antioxidants and contains several polysaccharopeptides that are associated with immune-boosting properties. Two bioactives in turkey tail are Krestin (PSK) and polysaccharide peptide (PSP) are well-studied both in vitro and in vivo.
It has been found in one phase I clinical trial to enhance immune responses in human breast cancer patients by stimulating T-cells, B-cells, and NK cells when taken at 6 or 9g daily for 6 weeks. According to one review, is also associated with suppressing inflammation, inhibiting the proliferation of cancer cells, helping cancer patients’ immune system fight tumors, and increasing the efficacy of chemotherapy drugs like docetaxel.
Eliza and colleagues demonstrated an increased rate of survival for cancer patients who took this mushroom, especially participants with breast, gastric, and colorectal cancers. In one study, PSK increased the survival rate significantly of stage II/III colorectal patients compared to controls.
Reishi (Ganoderma lucidum)
Known as Lingzhi or the “mushroom of immortality”, this mushroom is a very potent immune system regulator and stimulator. It has a balancing action on the immune system by being able to reduce immune system activity when overstimulated and support the immune system when weakened. In general, it increases the amount of active immune system cells.
This mushroom is associated with numerous anti-cancer properties according to one review such as inducing tumor cell death in various human and murine cell lines as well as reducing the chance of tumor metastasis, making it an ideal adjunctive therapy for cancer. Indeed, extracts from Reishi, specifically ganoderic acid, were recently found to increase the accumulation of the chemotherapeutic agent cisplatin inside tumor cells.
Reishi’s mechanism of action involves activating NK cells, white blood cells, and a number of bone marrow cells through main bioactive polysaccharides and proteins such as ganoderic acid, danderenic acid, lucidenic acid, and GLPS.
Chaga (Inonotus obliquus)
This mushroom has been used as a folk remedy over the centuries to treat various cancers in Russia and Siberia. Recent evidence suggests Chaga possesses anti-cancer effects, immunomodulatory properties, and could be a great immune enhancer during chemotherapy. In immunosuppressed mice, Chaga extract was found to increase the number of white blood cells in the blood marrow and chemically protective cytokines, giving it promising potential to recover the bone marrow system that is impaired during standard cancer therapies.
An additional study from 2015 found Chaga polysaccharide significantly increases macrophages in mice.
Its main bioactive compounds are thought to be triterpenes, and betulinic acid, as well as immune-enhancing phytochemicals present in many other medicinal mushrooms.
Shiitake (Lentinula edodes)
Shiitakes are one of the most popular and well-studied gourmet mushrooms. It contains a bioactive polysaccharide called Lentinan, which is a unique immunopotentiator capable of improving quality of life and extending survival in cancer patients.
Regular consumption (in this study, they consumed either five or ten grams of dried shiitake for 4 weeks) has been associated with improved immunity by improving NK cell proliferation and decreasing inflammation by its stabilizing effect on C-reactive protein and pro-inflammatory cytokines.
The mushroom also may help the body fight some types of cancer. In carcinoma, melanoma, and breast epithelial cell lines used in this 2006 study, shiitake mushrooms, specifically their ethyl acetate mycochemical constituents, were able to inhibit the growth of tumor cells and induce apoptosis, or programmed cell death.
Cordyceps (Cordyceps sinesis and Cordyceps militaris)
Also known as caterpillar fungus, this fungi lives on certain ceterpillars in the high mountains of China. It is used for many ailments in Traditional Chinese Medicine, including strengthening the immune system, kidney disorders, and improving athletic performance. Its main bioactives are cordycepin and nucleosides.
Hot-water extracts from Cordyceps militaris and Cordyceps sinensis have been implicated as a potent immune activator and anti-cancer adjunct treatment, with effects ranging from improving active immunity against cancer, activating apoptosis of cancer cells, and decreasing tumor size, to decreasing blood supply to cancer cells, and extending lifespan in cancer patients. In general, cordyceps has been shown to downregulate Th-2 cytokines, which is beneficial for cancer treatment. Additionally, cordycepin was found to induce apoptosis of human leukemia cells.
Host Defense has a variety of gluten free, organic non-gmo Cordyceps products.
Mushrooms and HIV/AIDS
The HIV virus selectively infects and kills helper T-lymphocytes resulting in severe immune suppression.
Mushrooms also have great potential to be an adjunct treatment for HIV alongside standard ARV therapies. Various bioactives polysaccharides, especially beta-glucans like lentinan from Shiitake, as well as many triterpenes, all possess immune-enhancing and anti-viral properties.
Triterpenes like ganoderic acid isolated from Reishi were found to possess anti-HIV properties. Beta-glucans found in the maitake mushroom increased CD4+ T-cells as well as increased subjective well-being in HIV patients.
Immune Assist 24/7 is one promising treatment approach which contains multiple polysaccharides derived from shiitake, reishi, cordyceps, turkey tail, and Agaricus brasiliensi. In a study of 8 HIV-infected patients, three tablets of 800mg three times daily produced a significant increase in T-lymphocyte levels. Host Defense offers this mushroom blend here.
Overall, promising anti-HIV properties have been noted in several in vitro studies and in some human trials, but more controlled clinical trials will have to be conducted to assess its efficacy as a therapeutic agent.
What is the best way to ingest mushrooms for their immune benefits?
Since many of the purported health benefits of medicinal mushrooms have been assessed in animal models where intraperitoneal injections were used of the bioactive extracts, it is difficult to say what the best route of ingestion is.
However bioactive polysaccharides, such as beta-glucans, are found in the fruiting bodies, cultured mycelia, and culture broth of the mushrooms discussed. Hot water and alcohol mushroom extracts in powdered form are the best choice, as this method is used in the available clinical trials. Mushroom sprays, such as the MycoShield Multi Mushroom Spray from Host Defense, contains a blend of several immune-supporting mushrooms in the form of mycelium extracts, but the precise polysaccharide percentages are not listed.
It’s clear that medicinal mushrooms offer great therapeutic potential in cancer patients and immunocompromised individuals due to the presence of several polysaccharides and other bioactive constituents that interact in an adaptogenic way with the innate and adaptive immune system.
When choosing to supplement medicinal mushrooms for immune support, opt for extracts to maximize the benefit, especially a blend of water and alcohol dual-extracts to harness the full spectrum of immune enhancement offered by these amazing fungi.