But, as a Jackson Laboratory (JAX) research team showed, mice that exercised avoided the kind of damage that in humans has been associated with dementia, stroke and other negative outcomes, despite being fed a and gaining significant weight.
In research published in the journal Neurobiology of Aging, the team fed genetically identical mice either a western diet or typical, grain-based mouse chow from age 2 to 12 months, roughly the equivalent of human middle age. The western-diet mice were further divided into exercisers and non-exercisers.
The brains of the western diet-fed mice that did not exercise showed inflammation, white matter damage and cerebrovascular decline. The western diet also appeared to adversely affect the normal repair process of myelin, the protective coating of nerve fibers. Collaborators at Indiana University showed that similar changes were observed in human subjects with high body mass indices.
Yet the mice that exercised avoided these pathologies. “Encouragingly,” says whose team performed the research, “a modifiable risk factor such as exercise appears to prevent the neuroinflammation and cerebrovascular and white matter damage that the chronic consumption of a western diet causes.”
Study lead author Leah Graham, Ph.D., noted, “Understanding how exercise mitigates damaging effects from a western diet and obesity will help identify new potential treatments for brain disorders.”
Graham et al.: Exercise prevents obesity-induced cognitive decline and white matter damage in mice. Neurobiology of Aging, published online May 3, 2019.