Researchers have found that a long-term high fat diet not only causes obesity, and other metabolic disorders, but also causes cognitive decline in the mice studied.
The research found that mice fed a high-fat diet for 30 weeks, resulting in diabetes, and a subsequent deterioration in their cognitive abilities, including developing anxiety, depression and worsening Alzheimer's disease.
Mice with impaired cognitive function were also more likely to gain excessive weight due to poor metabolism caused by brain changes.
Alzheimer’s disease has been tentatively linked with poor diet, in particularly a high-fat processed diet, and a sedentary lifestyle.
Study author UniSA neuroscientist and biochemist Associate Professor Larisa Bobrovskaya says the research adds to the growing body of evidence linking chronic obesity and diabetes with Alzheimer's disease, predicted to reach 100 million cases by 2050.
In the study the mice that were being fed the high-fat diet gained a lot of weight and then developed insulin resistance, but they also started behaving abnormally in comparison to the mice fed a standard diet.
Meanwhile the 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 stated: “"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."
Associate Professor Larisa Bobrovskaya continued: "Obesity and diabetes impair the central nervous system, exacerbating psychiatric disorders and cognitive decline. We demonstrated this in our study with mice."
Jing Xiong, Isaac Deng, Sally Kelliny, Liying Lin, Larisa Bobrovskaya, Xin-Fu Zhou.(2022) Long term high fat diet induces metabolic disorders and aggravates behavioral disorders and cognitive deficits in MAPT P301L transgenic mice. Metabolic Brain Disease, DOI: 10.1007/s11011-022-01029-x