What Do Obesity, Memory Problems, Stress, and Depression Have in Common?

Epigenetic links have been posited for the apparent relationships among obesity, cognitive decline, stress, and depression. Two studies in mice examine these relationships.

In mice with high-fat diet-induced obesity (DIO) and normal-weight mice, Heyward and colleagues elucidated the mechanism of the well-established association of obesity and memory impairment. On memory tests that required little exertion (because DIO mice are less active), DIO mice had preserved object recognition, but hippocampus-dependent spatial memory was impaired and long-term potentiation was reduced. Global DNA methylation in the hippocampus was similar in DIO and normal mice. However, late in the development of obesity, promoter regions of the gene for sirtuin1 (Si…