New research from the University of Minnesota sheds light on the relationship between obesity and an often-overlooked aspect of gut health: fungi.

While previous studies have examined the impact of diet on gut bacteria, this research – published this month – is the first to demonstrate a connection between fungi and diet. These findings give important support for the idea that gut fungal communities may contribute to metabolic health.

The project aimed to show whether fungal communities change when bacterial communities change, since researchers knew a high-fat diet impacts bacteria, said Abigail Johnson, a University postdoctoral associate and researcher on the study.

Researchers tackled this question by feeding mice either normal or high-fat chow to induce obesity, Johnson said.

They then used DNA samples from the mice to analyze microbiomes, said Tim Heisel, a University researcher with the project.

The study shows a high-fat diet impacts fungal communities and disrupts the structural and functional relationships between fungi and bacteria, said University researcher and grad student Gabriel Al Ghalith.

Since fungi make up a small proportion of gut DNA — there are about a million times more bacteria cells in the gut than fungi — many researchers assumed they didn’t play a significant role in metabolic health, Heisel said.

As a result, gut fungal communities are under-studied, Ghalith said.

This means researchers analyzing fungi aren’t able to reference previous studies on the subject, which makes researchers’ tasks even more difficult, Johnson said.

Recent research has shown that gut microbes play a role in the development of obesity, but these studies have focused on bacteria and ignored the potential impact of fungi on metabolic health.

“A lot more research needs to be done,” Johnson said.