Specific mushroom alters microbiome of mice to reduce obesity

Natural medicinal products are used around the world and prominently in Eastern civilizations. One such product, the Ganoderma lucidum mushroom has been used for centuries to promote better health. Scientific research has shown that polysaccharides (complex sugars) isolated from the fungus prevent fat cell formation in diabetic mice, and other isolates promote antidiabetic activity. Scientists in Taiwan were curious as to whether G. lucidum had any effect on body weight and obesity-related disorders such as chronic low-grade inflammation which leads to insulin resistance, type 2 diabetes, and fatty liver disease, and they published their results in Nature Communications.

The researchers tested whether water extract of G. lucidum mycelium (WEGL) can decrease obesity in high fat diet-fed mice (HFD).  A group of mice was fed a control chow diet, while another group was fed a high fat diet for 8 weeks. The chow and HFD-fed mice were treated daily with either water or WEGL at 2, 4, or 8% for two months.

The obese-human microbiome is often characterized by an increased Firmicutes- to-Bacteroidetes ratio. The researchers examined the gut microbiome of the mice and found that treatment of HFD-fed mice with 4% and 8% WEGL reduced the bacterial ratio to resemble one similar to that of chow-fed mice. In another test, 8% WEGL HFD-fed mice had an increased variety of bacterial species that negatively correlate with obesity, such as Parabacteroides goldsteinii, Anaerotruncus colihominis, Roseburia hominis, and more.  

WEGL fecal transplants were performed on some mice as well, which determined that it was indeed the altered gut microbiota of WEGL HFD-fed mice that is improved as the obese mice receiving the fecal transplant had reduced weight and a reduced Firmicutes-to-Bacteroidetes ratio. Overall, it appears that WEGL affects the gut microbiome of HFD-fed mice in a way that alters it to more closely resemble the microbiome of chow-fed mice. It was discovered that the high molecular weight polysaccharide fraction of WEGL may be responsible for its beneficial effects. While this is an exciting finding, this study was conducted in mice and it will be important to better understand the impacts this has on humans before people are out buying these mushrooms with the hope that it will lead to decreased obesity. 

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