By now, most of us have likely heard about the gut-brain axis and the growing body of research into the gut microbiome – the ecosystem of bacteria, viruses, and other microbes that inhabit our gastrointestinal system. I even covered this in a recent video.

Current research has been exploring how the microbes in the gut (and the substances they produce – known as metabolites) can influence overall health. Studies have shown that the diversity and richness of gut microorganisms can differ in conditions, including obesity, anxiety, depression, gastrointestinal and immune conditions, and many more. We also know that factors such as diet, environment, age, sex, and genetics can all impact the gut microbiome.

It’s also believed that gut microbiome changes take time, which is one reason why nutritionists like myself recommend introducing new diets to our pets gradually over several days.

Until recently, microbiome research has focused on how the gut affects the brain. However, a new study published in the peer-reviewed journal ‘Nature Metabolism’ has shown that the brain can, in turn, influence the composition of gut bacteria, increasing or decreasing certain bacterial families in mice within just 2 to 4 hours.

Like most research, the study has some limitations, and this is just one piece of research in an area that should be explored further. However, it throws up some interesting considerations, such as the importance of mood and brain function when assessing the gut microbiome and how testing may only provide us with a snapshot in time.

https://www.nature.com/articles/s42255-025-01280-3#data-availability