In their work, the scientists focused on the impact of obesity caused by poor nutrition and subsequent weight loss in young mice compared to mice that had reached middle age. In both groups, it was observed that losing excess weight contributed to the restoration of normal blood glucose levels, indicating key metabolic improvements regardless of age.
However, in the middle-aged mice, weight loss led to increased inflammatory processes in the hypothalamus—a region of the brain responsible for controlling appetite, energy expenditure, and other vital functions. This increase in inflammation was recorded at the molecular level and confirmed through detailed microscopic imaging of microglia, which are the brain's immune cells. This inflammatory response persisted for several weeks before gradually subsiding.
Although the long-term consequences of this inflammation remain unclear, the study's findings raise serious concerns. Chronic or poorly controlled inflammation in the brain is associated with memory deterioration and the development of neurodegenerative diseases such as Alzheimer's disease.
“Our data show that weight loss in middle age is not simply a replication of what happens in young people. Weight loss is important for restoring metabolic health in obesity; however, we need to understand how it affects brain health in middle age,” noted Alon Zemer, the lead author of the study.
The research team emphasizes the need for further studies to better understand the causes of temporary brain inflammation that occurs during weight loss in middle age. Future research may help develop strategies that preserve the metabolic benefits of weight loss while simultaneously protecting brain health.
