Fatty-food consumption triggers psychiatric disorders, increases depression risk

The study at Louisiana State University raises the possibility that a high-fat diet produces changes in health and behavior, in part, by changing the mix of bacteria in the gut, also known as the gut microbiome.

The human microbiome consists of trillions of microorganisms, many of which reside in the intestinal tract. These microbiotas are essential for normal physiological functioning. However, research has suggested that alterations in the microbiome may underlie the host's susceptibility to illness, including neuropsychiatric impairment.

Non-obese adult mice were conventionally housed and maintained on a normal diet, but received a transplant of gut microbiota from donor mice that had been fed either a high-fat diet or control diet. The recipient mice were then evaluated for changes in behavior and cognition.

The animals who received the microbiota shaped by a high-fat diet showed multiple disruptions in behavior, including increased anxiety, impaired memory, and repetitive behaviors. Further, they showed many detrimental effects in the body, including increased intestinal permeability and markers of inflammation. Signs of inflammation in the brain were also evident and may have contributed to the behavioral changes.

John Krystal, Editor of Biological Psychiatry, said that this paper suggests that high-fat diets impair brain health, in part, by disrupting the symbiotic relationship between humans and the microorganisms that occupy the gastrointestinal tracks. Indeed, these findings provide evidence that diet-induced changes to the gut microbiome are sufficient to alter brain function even in the absence of obesity. Further research is necessary, but these findings suggest that the gut microbiome has the eventual potential to serve as a therapeutic target for neuropsychiatric disorders.

The study is published in the Biological Psychiatry.