Mushrooms are somewhat neglected in medical research, I often feel. This systematic review focused on clinical studies testing the effectiveness of mushrooms in cancer care. A total of 39 met the authors’ inclusion criteria. The studies included 12 different mushroom preparations. Some of the findings were encouraging:
- A survival benefit was reported using Huaier granules (Trametes robiniophila Murr) in 2 hepatocellular carcinoma studies and 1 breast cancer study.
- A survival benefit was also found in 4 gastric cancer studies using polysaccharide-K (polysaccharide-Kureha; PSK) as an adjuvant therapy.
- Eleven studies reported a positive immunological response.
- Quality-of-life (QoL) improvement and/or reduced symptom burden was reported in 14 studies using various mushroom supplements.
- Most studies reported adverse effects of grade 2 or lower, mainly nausea, vomiting, diarrhea, and muscle pain.
The authors caution that limitations included small sample size and not using randomized controlled trial design. Many of the reviewed studies were observational. Most showed favorable effects of mushroom supplements in reducing the toxicity of chemotherapy, improving QoL, favorable cytokine response, and possibly better clinical outcomes.
The authors concluded that the evidence is inconclusive to recommend the routine use of mushrooms for cancer patients. More trials are needed to explore mushroom use during and after cancer treatment.
The use of mushrooms for medicinal purposes has a long history in many cultures. Some mushrooms are known to be highly poisonous, some have hallucinogenic effects, and some are assumed to have pharmacological effects that have therapeutic potential. Some mushrooms possess pharmacologic properties such as anti-tumour, immunomodulating, antioxidant, cardiovascular, anti-hypercholesterolemic, anti-viral, anti-bacterial, anti-parasitic, anti-fungal, detoxification, hepatoprotective, and anti-diabetic effects.
Many modern medicines were derived from fungi. The best-known example is penicillin; others include several cancer drugs, statins and immunosuppressants. In Traditional Chinese Medicine, numerous herbal mixtures contain mushrooms; examples are reishi, maitake and shiitake which are all assumed to have anti-cancer properties.
As the review authors point out, there is a paucity of clinical trials testing the effectiveness of mushrooms, and the existing studies tend to be of poor quality. At present, most of our knowledge comes from traditional use or test-tube studies. The adverse effects depend on the specific mushroom in question and, can in some instances, be serious.
Considering the potential and the complexity of mycomedicine, I find it surprising to not see much more research into this subject.