The human gut is home to over a trillion microbes, and it’s becoming increasingly clear that this swirling mass of life impacts our health in profound and important ways. Adding to this growing body of evidence, researchers have now apparently found that a certain type of mushroom, used in Chinese medicine for centuries, might alter this delicate bacterial composition in mice, helping them to slow weight gain.
The researchers, from Chang Gung University in Taiwan, found that the mushroom Ganoderma lucidum reduced weight gain in mice fed a high fat diet compared to those eating the same diet but without the extract. Whether this study is transferable to humans is not yet known, though the results are intriguing. The study is published in Nature Communications.
The composition of the bacteria in your gut, known as the microbiome, is thought to at least in part contribute to obesity and weight gain. For example, earlier this year it was reported that an otherwise healthy-sized woman who received a fecal transplant – used to cure her from a chronic C. difficile infection – from her obese daughter later became obese herself.
Considering that the bacteria in your gut contribute to nutrient acquisition and energy regulation, it may not come as a surprise that they could also have a role in weight gain. To test how the mushroom could influence the bacteria in the guts of mice, the researchers fed two groups of mice on a high fat diet. At the same time, they gave one group the mushroom extract and not the other.
What they found was that the mice on the diet and without the fungus gained a total of 42 grams over two months, while those also being fed the extract only gained 35 grams over the same period. So while it didn’t prevent weight gain, it certainly slowed it. Then, to test if this was indeed a result of an alteration to the animals' microbiomes, the researchers gave a fecal transplant from the mushroom-fed mice to the others.
The procedure successfully transferred the benefit gained by eating the fungus to those that hadn’t fed on it, helping the obese mice to keep off the pounds, pointing quite firmly to a bacterial component. Before you get too excited, no one is suggesting that sprinkling the mushroom on all of your food will stop you from gaining weight. For a start, we currently do not know whether it will have the same impact on people, and additionally, the slimmest mice in the study were those that were simply fed a normal, healthy diet.