Changes in bacteria in the gut are linked to critical psychological changes,
a new mouse study finds.
A high-fat diet could increase the risk of repetitive behaviours, depression and anxiety, researchers have concluded.
Dr. John Krystal, editor of journal Biological Psychiatry, where the article was published, said:
“This paper suggests that high-fat diets impair brain health, in part, by disrupting the symbiotic relationship between humans and the microorganisms that occupy our gastrointestinal tracts.”
As the authors write, this is the…
“…first definitive evidence that high-fat diet-induced changes to the gut microbiome [the community of organisms in the human gut] are sufficient to disrupt brain physiology and function in the absence of obesity.” (Annadora et al., 2015)
In the study, non-obese mice were fed a normal diet.
But they were then given the gut microbiota — the microorganisms which live in the gut — from another mouse which had been fed a high-fat diet.
These were compared with mice who were given gut microbiota from a mouse fed on a normal diet.
Remarkable changes were seen in the non-obese mice that had been given the microbiota from the high-fat mice.
They showed signs of depression, anxiety, memory problems and repetitive behaviours.
There were also signs of brain inflammation.
High-fat diets have long been known to increase the risk of physical problems like stroke and heart disease.
This study is part of a growing body of research showing the link between brain and gut.
For example, the first ever human study of its kind recently found that consuming a prebiotic bacteria can have an anti-anxiety effect.
The authors conclude:
“…these data are in agreement with the extensive body of literature describing the sensitivity of the brain to diet-induced obesity and the growing number of studies linking gut microbiota to central nervous system health and behavior.
For example, there is a reported high comorbidity [overlap] between psychiatric syndromes, including depression and anxiety, with gastrointestinal disorders, while conversely, recent studies link probiotics to positive changes in mood and behavior.”