PLOS: Fatty foods impair brain function

A diet rich in fatty foods not only increases the risk of obesity and diabetes but can also impair brain function, accelerating the development of neurodegenerative diseases, including Alzheimer’s disease. This conclusion was reached by researchers at Chiba University in Japan. The study was published in PLOS Genetics.

The scientists showed that a high-fat diet disrupts autophagy — the “cellular waste recycling” process vital for neuron health. Experiments on fruit flies revealed that defects in this mechanism damage long-term and intermediate memory, while short-term memory remains unaffected.

“Our results suggest that diet-induced memory impairment is not irreversible and can be improved through interventions that stimulate autophagy, such as physical exercise or intermittent fasting,” noted study leader Associate Professor Ayako Tonoki.

To test the link between diet and cognitive functions, the flies were kept on either a normal or high-fat diet for one week. Those fed fatty foods showed higher levels of lipids and glucose, along with poorer performance in memory tests. Protein analysis confirmed impaired autophagy: the number of “recycling” cellular vesicles dropped, while accumulation of the marker protein Ref(2)p increased.

Crucially, memory function was restored through artificial enhancement of autophagy — both via genetic methods and through the use of the compound rapamycin.

The researchers also discovered that the main problem lay in the final stage of cellular “waste disposal” — the fusion of autophagosomes and lysosomes. In animals on a high-fat diet, this process was blocked, as confirmed by changes in the expression of lysosome-related genes.

“Our study demonstrates how directly our eating habits affect brain health. It also brings us closer to developing strategies — from nutritional choices to new drugs — that can help protect cognitive function and slow brain aging,” Tonoki emphasized.