Mushrooms play a hidden role in gut health

The Research Brief is a brief presentation of interesting academic work.

The big idea

Mice with specific fungal communities living in their gut gained more weight from consuming processed foods than mice whose gut microbiomes harbored different fungal communities. This is evident from our study published March 5th in the journal Communications Biology.

Microbiomes are communities of microorganisms. In this study, we investigated whether the fungus members of the gut microbiome – called the mycobioma – have altered their host’s metabolic response to processed foods. To do this, we received genetically identical mice from four different companies – each with different fungal microbiomes – and fed the mice either standard mouse chow or processed chow similar to the typical American diet. After six weeks, we measured her body fat and the genes and hormones involved in metabolism.

We specifically studied the relationship between the fungal microbiome and processed foods – foods containing, for example, refined sugars, monounsaturated fats, and white flour – as these foods have been linked to unhealthy weight gain in humans. Eating processed foods made most mice fatter, but how much weight and how their metabolism changed varied between mice with different microbiomes. After measuring the microbiomes of each mouse, we used machine learning to find out which fungi had the greatest impact on metabolism.

We found that mice whose gut microbiomes contained more Thermomyces fungi – which manufacturers use to break down fat in commercial processes – and fewer Saccharomyces – yeasts used in baking and brewing – gained about 15% more weight than mice with different microbiomes . We found similar but smaller differences in mice on normal diets.

Why it matters

The gut microbiome can affect metabolism.

Most people assume that the microbiome is made up entirely of bacteria. Fungi – although usually less common than bacteria – are often critical members of these microbial communities. Microbiomes vary between individuals, so the types of fungi that live in your gut may be different from those of your neighbor. This also applied to the mice in our study.

Researchers have only recently discovered the fungal microbiome and have limited knowledge of how it affects human health. Our study is one of the first to determine how intestinal fungi can affect metabolism.

If intestinal fungi affect metabolism in humans in a manner similar to that in mice, researchers may be able to develop diets that are tailored to specific microbiomes. It might also be possible to adjust a person’s fungal microbiome to help control weight in certain situations – for example, after weight loss surgery.

Which is not yet known

Scientists are still learning what types of mushrooms make their home in the gut versus mushrooms that may be just coming through. While many of the interactions between people and their intestinal fungus are likely to be beneficial, it may not always be. For example, mushrooms can play a role in irritable bowel syndrome and increase the risk of developing pancreatic cancer.

Not only could the presence or absence of certain fungi have direct health effects, but the interaction of fungi with bacteria is likely very important too. Our work has taken some important first steps to understand the complex relationship between bacterial and fungal communities as they work together to digest processed foods.

What’s next

We plan to conduct studies in humans and mice to investigate how the fungal microbiome affects metabolism in high fat diets and after weight loss surgery. To learn more about how different fungi affect metabolism, we would like to make mice with artificial microbiomes that we either assemble ourselves or transplant from a human donor.

This article was originally published on The Conversation by Kent Willis and Justin D. Stewart at UCL. Read the original article here.

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