Cochrane: Cardiovascular disease is the name given to any disease, such as
heart attack or stroke, that affects the heart and circulatory system
(which moves blood around the body). Risk factors for cardiovascular diseases include high blood pressure, and high levels in the blood of glucose and cholesterol. People with cardiovascular risk factors are more likely to have a heart attack or stroke than people without them. Ganoderma lucidum (G lucidum), also known as 'lingzhi' or 'reishi', is a mushroom that is commonly used in traditional Chinese medicine.
In China, G lucidum
is taken in the traditional form of a decoction (mashed and boiled in
water), or in tea or coffee. Recently it has been manufactured as an
extract in tablets and capsules for the western market, as it is now
being used in western countries in the hope that it might improve cardiovascular health.
The purpose of this review
Researchers from the Cochrane Collaboration tried to determine whether G lucidum, when compared with another medicine or a fake medicine – called a placebo – is an effective treatment for reducing cardiovascular risk factors.
What this review discovered
The researchers searched the medical literature up to June 2014 to identify all the relevant medical research. They identified a total of 5 medical studies that compared G lucidum with placebo in a total of 398 people with type 2 diabetes. Overall the quality of the studies was poor. Unpublished data was obtained for two of the included studies and one study was translated from Chinese. The daily doses of G lucidum taken varied between trials from 1.4 g to 5.4 g. In 1 trial participants in the G lucidum group took capsules that contained either G lucidum only, or a mixture of G lucidum (75% of capsule weight) and another fungus called Cordyceps sinensis (25% of capsule weight). Duration of trials varied from 12 to 16 weeks.
Two of the 5 trials reported results for the participants treated with G lucidum only, but not for those treated with placebo, and so the information from them could not be used. The remaining 3 trials with 157 participants provided information for analysis.
This information showed that G lucidum was not an effective treatment for reducing blood glucose, blood pressure, or cholesterol. It was not clear whether G lucidum might reduce blood glucose after a meal, as the only information for this came from a single study of indeterminable quality.
There was not enough information to determine the overall safety of taking G lucidum. One study showed some increased risk of mild harms in participants who took G lucidum in the form of nausea, diarrhoea or constipation.
Future research in this field should include clinical trials that are better reported.