In Addition to Obesity, Diets High in Fat Can Also Cause Cognitive Decline

A study, conducted on animals by a team from the University of South Australia, confirms that an excessively fat diet not only surprisingly leads to more fat in the abdominal area, but also shrinks the brain, increasing the risk of developing dementia, including Alzheimer’s disease. The study which was published in the journal Metabolic Brain Disease reminds us of the strong link between metabolism, cerebrovascular health, and cognition and makes us aware of the central role of diet.

Obese Woman

The study clearly shows that in mice fed a diet rich in fat for 30 weeks – which leads to diabetes – there is a link between excess dietary fat and the subsequent decline in cognitive abilities that follows, with the added bonus of developing mental conditions such as depression and anxiety. In mice already suffering cognitive decline, such a high-fat diet exacerbates Alzheimer’s disease.

In the study, the mice were randomly assigned to either a regular diet or a diet high in fat for 30 weeks, starting at 8 weeks of age. The amount of food, body weight, and glucose levels were all monitored at different times during the study, and glucose and insulin intolerance tests and cognitive tests were also performed.

The study shows that the mice that were fed a high-fat diet became obese, developed insulin resistance, and began to behave abnormally in comparison to their counterparts on the standard diet.

Alzheimer’s model mice fed the high-fat diet showed a rapid and significant decline in cognition with visible pathological changes in the brain.

Obesity and diabetes both alter the central nervous system thereby worsening psychiatric disorders, and causing rapid cognitive decline. But the link also holds in the other direction: mice whose cognitive function is already impaired are also more likely to become overweight due to poor metabolism, which is also caused by these brain changes.

This work adds to the growing body of scientific evidence that already links chronic obesity and diabetes with Alzheimer’s disease whose prevalence could reach 100 million cases by 2050. It suggests that a more balanced diet could also help reduce the burden of this cognitive epidemic. Obese people have an approximately 55% higher risk of developing depression and diabetes further doubles this risk.

These findings highlight the importance that should be given to the global obesity epidemic. In an aging population, the combination of obesity and diabetes is very likely to lead to rapid cognitive decline, Alzheimer’s disease, and other mental disorders.