For many centuries, reishi mushroom has been tied to several beneficial properties when it comes to improving health and treating diseases. The secret behind all this propaganda surrounding reishi mushrooms goes back to its rich nutritional composition which gives it an edge when compared to other medicinal mushrooms from the same origin.
In fact, Paul Stamets, a medical researcher, and mycologist says “Today, reishi stands out as one the most valuable of all polypore mushrooms in nature for the benefit of our health. Many naturopaths and doctors prefer organically grown reishi from pristine environments because they are purer.”
In this article, we’re going to take a deep dive into the diverse benefits and use of reishi mushrooms as foretold and evidenced by science.
- Benefits of Reishi Mushrooms
- Possible Risks and Side Effects
- The Bottom Line
Benefits of Reishi Mushrooms
Many studies have mentioned the superior effects of reishi mushrooms on the human body, and how they may be used to treat several health conditions due to their antioxidant, anti-inflammatory, anticancer, antimicrobial, and immune-boosting properties. Below is a list of the health benefits that have been discovered by scientific studies thus far, these include the following:
1. Boosting the Immune System
When it comes to the immune system, reishi mushrooms have been linked to boosting immunity upon their consumption. This is primarily done through the following three mechanisms which are:
- Stimulating the immune system to activate immune cells
- Protecting the body against external threats (these include foreign pathogens like bacteria, fungi, or viruses)
- Managing autoimmune diseases (when the body’s cells, tissues, or organs attack itself)
- Regulating inflammation (anti-inflammatory function), and clearing toxins from the body
The immune-boosting property of the reishi mushroom was proven in a review study that was published in the journal of Pharmacological Sciences in 2005, which explains that the reishi mushroom holds an effect on antigen-presenting cells, mononuclear phagocyte system and promotes both humoral immunity, and cellular immunity.
As for inflammation, a study published in the Journal of Nutrition and Cancer in 2010, reveals that a specific type of reishi mushroom plays a role in controlling the gene expression of certain inflammatory pathways.
Other immune functions of the reishi mushroom in managing autoimmune diseases and immunodeficiencies are illustrated in a review study published in the Journal of Hematology/Oncology and Stem Cell Therapy in 2015, which explains the positive impact of the reishi mushroom on Natural killer cells (a type of immune cell responsible for protecting the body against internal threats like cancer, viruses or autoimmune diseases), and how they can be used in combating these types of immune diseases.1–6
2. Anti-Cancer Properties
Reishi mushroom is known for their anti-cancer activity which plays a role in eliminating internal threats, especially cancer.
This anti-cancer activity of reishi mushrooms was evidenced through two studies, the first was a clinical trial published in the Journal of Immunological Investigations in 2003, which showed that reishi mushrooms enhanced the immune responses in patients who had cancer in the late stages.
The second study was published in the Journal of International Immunopharmacology in 2006, which indicated that the reishi mushroom had immunomodulating properties in patients with advanced stages of colorectal cancer. However, both studies recommend further investigations to confirm their safety and efficacy.
3. Managing High Blood Pressure
Reishi mushrooms have the potential in normalizing heart health and fight high blood pressure through the following mechanisms:
- Increasing blood flow
- Reducing blood pressure
- Increasing good cholesterol (called HDL)
- Promotes weight loss
For example, a study that was published in the journal Molecules in 2014, showed that reishi mushrooms may be a very good source of hypotensive peptides (molecules that can lower high blood pressure), which makes reishi mushrooms a good candidate as an antihypertensive agent.
Moreover, another study that was published in the British Journal of Nutrition in 2012, reveals that the reishi mushroom reduces cholesterol levels, body weight, and high blood pressure.7,8
4. Diabetes Mellitus Treatment
Diabetes mellitus is one of the most common and serious diseases out there, in fact, it’s estimated that the number of people who suffer from diabetes in the US is 34.2 million people. So, when the reishi mushroom was associated with regulating blood sugar levels, it was a pleasant surprise!
Evidently, pre-clinical research conducted on lab animals has reported back the positive impact of the reishi mushroom as an antidiabetic agent owing to molecules found in its composition which help in reducing sugar levels in the blood. A study in the Journal of Archives of Pharmacal Research in 2012, found that taking reishi mushrooms significantly reduced fasting serum blood glucose levels in lab mice.
Similarly, another study published in PloS one in 2013, revealed that aside from the antidiabetic effects of reishi mushrooms, they also contain antioxidant properties which help in managing diabetes complications as well.
As for reishi mushrooms’ antidiabetic effects on humans, a study published in the International Journal of Medicinal Mushrooms in 2004, uncovered the safety and efficacy of utilizing reishi mushrooms in lowering blood sugar levels in patients with type 2 diabetes.9–11
5. Improving Liver Health
Reishi mushrooms are considered natural liver tonics (herbs that improve the functions of the liver) as they provide the liver with the following functions:
- Managing liver enzymes
- Anti-inflammatory and antioxidant properties
- Reversing liver fibrosis
- Clearing toxic metabolites
- Destroying viral threats to the liver (ex. Hepatitis)
- Boosting immune activities of Kupffer cells
- Protecting the liver and promoting cells regeneration
A study published in the International Journal of Medicinal Mushrooms in 2013, reports that reishi mushrooms may help in treating acute liver injury due to their antioxidant properties. Moreover, another study published in the journal of Pharmacology in 2019, adds that aside from their antioxidant properties, reishi mushrooms also have anti-inflammatory properties which protect the liver and help in treating liver injury.
Similarly, a recent study published in the journal of Cytokines in 2020, discovered that reishi mushrooms play a role in intercepting and inhibiting inflammatory pathways which participate in liver injury.12–15
6. Antioxidant Activity
Although not supported by many studies — reishi mushrooms have been implicated in enhancing the antioxidant activity in the body. The growing interest in food and supplement sources with antioxidant activity has grown significantly owing to their benefits in preventing and treating many diseases caused by cell damage (ex. Fibrosis and cirrhosis of the lungs or the liver).
One study that was published in the International Journal of Medicinal Mushrooms in 2021, concluded that reishi mushrooms have very active and rich antioxidant properties. In fact, the authors said “G. lucidum could be used as a source of strong natural antioxidants for the food and pharmaceutical industries.”16
7. Weight Loss
Following a healthy diet and exercising regularly is one of the main steps of losing weight. Thus, researchers tried to investigate the effect of the reishi mushroom on losing weight, since it has already been implicated with various health benefits that improved the quality of life of many people.
An example of these investigations includes a study published in the Journal of Medicinal Food in 2018, which discovered that the reishi mushroom in fact has hypolipidemic (lipid-lowering) effects in obese mice.17
8. Fighting Depression
Apart from treating physical ailments — some preliminary evidence suggests that reishi mushrooms may also be beneficial in improving mental health by treating depression and fighting fatigue.
For depression, a recent study published in the journal Brain Research Bulletin in 2021, declared that reishi mushrooms are a novel and rapid antidepressant with clinical potential and multiple beneficial mechanisms, particularly in regulating the neuroimmune system.
As evidenced by clinical trial results published in the Journal of Medicinal Food in 2005, reishi mushroom improved symptoms of neurasthenia (an ailment associated with emotional disturbances and extreme fatigue) in 132 patients when compared to those who took the placebo.18–20
9. Alleviating Fatigue
Reishi mushroom has also shown some promise when it comes to treating extreme tiredness and fatigue whether it’s a side effect of other diseases (like neurasthenia) or treatments (like chemotherapy).
According to a study conducted on breast cancer patients which was published in the journal of Evidence-Based Complementary and Alternative Medicine in 2012, reishi mushroom improved fatigue symptoms associated with cancer and significantly improved patients’ quality of life.
Possible Risks and Side Effects
To this day, there hasn’t been enough body of evidence on the effects of reishi mushrooms on humans to validate their safety without an issue of doubt. However, it’s recommended that you consult your doctor first before taking it so that they see if you’re the right candidate for it.
Possible side effects to look out for include the following:
- Chronic diarrhea
- Dryness in the mouth, nose, and throat
- Feeling itchy
- Bloody stool
- Bleeding nose
- Stomach upset
- Liver toxicity
Liver toxicity is one of the most fatal complications that has been encountered so far with reishi mushrooms. This was reported back in two case studies of patients who took reishi mushroom in powder form and subsequently developed liver toxicity that lead to one patient losing their life. 21–23
However, several factors may have contributed to the above findings.
Reishi mushroom selection – There are more than a thousand types of reishi mushrooms, and only a few are beneficial to our health. For instance, reishi mushrooms grown on lacquer trees, maple trees, and willow trees are known to be toxic. Also, reishi grown in toxic environments are known to be poisonous because it absorbs from its surrounding environment. Further, reishi mushrooms that are not properly stored can become toxic because of mold or other fungus growing on or inside of it.
Reishi mushroom processing – How reishi mushrooms are processed can also affect its toxicity. For instance, it is known that different levels of heat treatment for reishi produce different amounts of sugar and probiotic L. casei. If reishi is not processed or extracted properly (or whether any chemical compound was used), toxicity can be the result.
Thus, it is likely that the side effects of reishi from these scientific studies are a cause of improper reishi mushroom selection or processing.
There are several considerations to take before deciding on the dosage of reishi mushrooms, these include the following:
- Form of reishi mushroom (ex. Fresh reishi mushroom, capsules, extract, or powder form)
- Other medications being used
- Type and size of reishi mushroom
- Product type
- Overall health and medical history of the individual
So, you must talk with your healthcare provider first so that they can guide you towards the most suitable dosage and form of reishi mushroom to use.
The Bottom Line
Reishi mushrooms have been utilized extensively in traditional medicine owing to their diverse health benefits and positive effects on improving the lives of many people who suffer from diseases whether mental or physical. Although there’s still a need for further investigations on the safety and effectiveness of reishi mushrooms, many research studies have already proven the positive benefits of reishi mushrooms on humans.
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2. Zhang Y, Lin Z, Hu Y, Wang F. Effect of Ganoderma lucidum capsules on T lymphocyte subsets in football players on “living high-training low.” Br J Sports Med [Internet]. 2008 Oct [cited 2022 Aug 11];42(10):519–22. Available from: https://pubmed.ncbi.nlm.nih.gov/18048435/
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17. Liang Z, Yuan Z, Li G, Fu F, Shan Y. Hypolipidemic, Antioxidant, and Antiapoptotic Effects of Polysaccharides Extracted from Reishi Mushroom, Ganoderma lucidum (Leysser: Fr) Karst, in Mice Fed a High-Fat Diet. J Med Food [Internet]. 2018 Dec 1 [cited 2022 Aug 12];21(12):1218–27. Available from: https://pubmed.ncbi.nlm.nih.gov/30183494/
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