High-fat diet linked to anxiety, depression and Alzheimer's in mice

Fatty foods could cause anxiety, depression and cognitive difficulties, as well as making people overweight, a study has warned.

The University of South Australia study looked at mice fed a high-fat diet for 30 weeks, a long period in terms of mouse lifespans.

Researchers found a clear link between the high-fat diet and subsequent deterioration in their cognitive abilities, including developing anxiety, depression and worsening Alzheimer’s disease.

The mice also developed diabetes.

Neuroscientist and biochemist Associate Professor Larisa Bobrovskaya said: "Obesity and diabetes impair the central nervous system, exacerbating psychiatric disorders and cognitive decline. We demonstrated this in our study with mice.

Read more: Obesity at 'epidemic levels in Europe'

"Obese individuals have about a 55% increased risk of developing depression, and diabetes will double that risk.

"Our findings underline the importance of addressing the global obesity epidemic. A combination of obesity, age and diabetes is very likely to lead to a decline in cognitive abilities, Alzheimer’s disease and other mental health disorders."

The research was published in the journal Metabolic Brain Disease.

The researchers said the study added to the growing body of evidence linking chronic obesity and diabetes with Alzheimer’s disease, predicted to reach 100 million cases in humans by 2050.

In the study, mice were randomly allocated to a standard diet or a high-fat diet for 30 weeks, starting at eight weeks of age.

Read more: Childhood obesity reaches ‘epidemic’ levels due to Covid lockdowns

Food intake, body weight and glucose levels were monitored at different intervals, along with glucose and insulin tolerance tests and cognitive dysfunction.

The mice on the high-fat diet gained a lot of weight, developed insulin resistance and started behaving abnormally compared to those fed a standard diet.

Genetically-modified Alzheimer’s disease mice showed a significant deterioration of cognition and pathological changes in the brain while fed the high-fat diet.

The researchers found that mice with impaired cognitive function were also more likely to gain excessive weight due to poor metabolism caused by brain changes.

Watch: Diabetes drug leads to significant weight loss in those with obesity