Reishi mushroom (Ganoderma lucidum) is a fungus that is used in the traditional medical systems of China, Japan, Korea, and other Asian countries. Reishi supplements come as capsules, tablets, extracts, powders, and teas.
Claims for Reishi
Reishi mushrooms are said to treat elevated cholesterol levels or other hyperlipidemia. They are also said to boost the immune system, increase strength and stamina, treat cancer, and treat lower urinary tract symptoms in men.
Evidence for Reishi
A 2016 Cochrane systematic review of use of reishi for treatment of cancer included 5 randomized, controlled-trials (373 patients) (1). The analysis found that patients who were given reishi in combination with their chemotherapy/radiation therapy had greater tumor regression with treatment than those treated with chemotherapy/radiation therapy alone, and quality of life improved. Treatment with reishi alone did not show a benefit. There was no evidence of survival benefit.
A systematic review of use of different medicinal mushrooms in cancer patients reported that reishi may improve physical symptoms and quality of life, although there was significant heterogeneity in the included studies (2).
Reishi may potentially have antiviral effects against dengue, enterovirus, other viruses and microbes (3).
Adverse Effects of Reishi
Nausea, insomnia, liver toxicity, anorexia, and chronic diarrhea have been reported. Although safety of long-term use has been reported, there is no information on the use of reishi in pregnancy or lactation.
Drug Interactions with Reishi
Reishi may increase the risk of bleeding in patients treated with antiplatelet and anticoagulation medications. It may also produce hypotension with antihypertensives and additive hypoglycemia with antihyperglycemic medications.
References
1. Jin X, Ruiz Beguerie J, Sze DM, Chan GC. Ganoderma lucidum (Reishi mushroom) for cancer treatment. Cochrane Database Syst Rev. 4(4):CD007731, 2016. Published 2016 Apr 5. doi:10.1002/14651858.CD007731.pub3
2. Narayanan S, de Mores AR, Cohen L, Anwar MM, Lazar F, Hicklen R, Lopez G, Yang P, Bruera E. Medicinal Mushroom Supplements in Cancer: A Systematic Review of Clinical Studies. Curr Oncol Rep. 2023 Jun;25(6):569-587. doi: 10.1007/s11912-023-01408-2
3. El Sheikha AF. Nutritional Profile and Health Benefits of Ganoderma lucidum "Lingzhi, Reishi, or Mannentake" as Functional Foods: Current Scenario and Future Perspectives. Foods. 2022 Apr 1;11(7):1030. doi: 10.3390/foods11071030
