A high-fat diet may be harmful for mental health, potentially leading to depression, according to a new study. Such a diet can also lead to brain inflammation and affect behavior, new research reveals.
Eating foods high in fat has been tied to physical health problems, including an increased risk of heart attacks and strokes.
The gut microbiome, the complete mixture of bacteria in the digestive system of humans, can be altered by consumption of a diet rich in fat, researchers theorize. A typical body contains trillions of microorganisms.
Mice who were fed a normal diet were implanted with bacteria from rodents who had consumed large amounts of fat. These animals were then monitored over time, and their behavior and cognition were measured against a control group who received microbes from mice fed a normal diet.
Louisiana State University researchers wanted to know whether bacteria in the gut can alter behavioral patterns, even in animals who do not exhibit obesity.
Mice who received bacteria from rodents fed a diet high in fat were found to exhibit repetitive behaviors, anxiety and memory impairment. The animals also showed signs of inflammation and increased permeability in their intestines.
Brain inflammation observed in the mice with fat-fed bacteria may have been responsible for behavioral changes seen in the rodents.
"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," John Krystal, editor of Biological Psychiatry, said.
This new study suggests that behavioral changes caused by consumption of a high-fat diet can take place even in animals that are not obese. The mechanism by which a high-fat diet causes mental changes is still unknown, and future research could examine how bacteria in the gut could alter behavior.
Previous research has found correlations between gut bacteria and certain psychological conditions. This new study provides more evidence supporting these earlier findings. Alterations in the microbiome have also been tied to the ability of bodies to fight off illness and heal from injuries.
Obesity and depression are both known to be strongly influenced by genetics, and each condition can compound the other issue. Depressed people often eat fatty foods as a means of feeling better, but obesity, and the social stigma attached to it, can increase feelings of depression.
"One recent study found that overall, obese individuals have a 20 percent elevated risk of depression, and specifically for Caucasian college-educated people with obesity, the depression risk rises to as high as 44 percent," the Obesity Action Coalition reports.
This new study could show an additional tie-in between the two conditions.
Analysis of the role of high-fat diets and gut bacteria on mental health was profiled in the journal Biological Psychiatry.
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