The efficacy of Ganoderma lucidum for treatment of cardiovascular risk factors

Abstract

Background Cardiovascular disease is the world's leading cause of death and disability. In recent years the Chinese medicinal mushroom Ganoderma lucidum, also called ling zhi or reishi, has been marketed in Western countries with claims to improve cardiovascular risk factors. These factors include elevated blood glucose, elevated blood pressure and abnormal lipid profiles. Research about the effects of Ganoderma lucidum in humans is limited. The studies that exist might have methods or reporting that introduce potential for bias. Therefore, the effectiveness of Ganoderma lucidum for treatment of cardiovascular risk factors has not been clearly established. Aim The aim of this research was to evaluate the efficacy and safety of Ganoderma lucidum for the treatment of pharmacologically modifiable cardiovascular risk factors. Method Two studies were conducted in this research. The first study was a randomised controlled clinical trial to evaluate the efficacy and safety of Ganoderma lucidum for treatment of hyperglycaemia and other cardiovascular risk components of the metabolic syndrome. Eighty-four participants with type 2 diabetes mellitus and metabolic syndrome from Sydney, Australia were randomised to one of three intervention groups: Ganoderma lucidum, Ganoderma lucidum with Cordyceps sinensis or placebo. The dosage was 3 grams Ganoderma lucidum per day for 16 weeks. The study utilised a clinical trial design with randomisation, allocation concealment and blinding of participants, therapists and assessors. The primary outcome measure was blood glucose and the other components of the metabolic syndrome were the secondary outcomes for this study. The second study was a systematic review to evaluate effects of Ganoderma lucidum on cardiovascular risk factors. Included trials required participants to have received treatment for at least one cardiovascular risk factor. Twenty-two English and Chinese language databases were searched for randomised and controlled clinical trials. Specified journals and reference lists were hand-searched and experts in the field were contacted to locate additional sources. The primary outcome measures were blood glucose, blood pressure and lipid profile. Two authors independently selected trials, assessed risk of bias and cross-checked the data extraction and analysis results. Results Seventy-three participants completed the clinical trial. No effects attributable to Cordyceps sinensis were detected, and therefore the data for the two active intervention groups were combined for all further analyses. Ganoderma lucidum did not reduce glycosylated haemoglobin (HbA1c) or fasting plasma glucose during the 16-week treatment period. The treatment effect for HbA1c was 0.13 per cent (95 per cent confidence interval [CI] of -0.35-0.6) (p=0.6), and for fasting plasma glucose 0.03mmol/L (95 per cent CI of -0.9-0.96) (p=0.95), both in favour of the control group. Clinical trial secondary outcomes were blood pressure, triglycerides, high-density lipoprotein cholesterol (HDL-C), metabolic syndrome diagnostic status and health-related quality of life. For each of these, no statistically or clinically significant differences between Ganoderma lucidum groups were detected. There was no overall increased risk of adverse events for persons taking Ganoderma lucidum (161 per cent v. 160 per cent; RR 1.01, 95 per cent CI not estimable). However, Ganoderma lucidum was associated with increased risk of a subset of mild events of headache, fatigue, and gastrointestinal effects (57 per cent v. 33 per cent; RR 0.37, 95 per cent CI 0.15-0.94). The systematic review identified four trials eligible for inclusion, with 375 participants. One of these was our unpublished randomised controlled trial, which was awarded a low risk of bias. The other three studies had an unclear risk of bias. Due to incomplete reporting, only one outcome from one study was suitable for meta-analysis with our clinical trial results. Results from the pooled data of 134 persons found Ganoderma lucidum was not associated with a clinical or statistical reduction in HbA1c (WMD: -0.10 [95 per cent CI -1.05-0.85]). Conclusion Evidence from this randomised clinical trial and systematic review does not support the use of Ganoderma lucidum for treatment of cardiovascular risk factors in people with diabetes mellitus.

Date of Award	2012
Original language	English