Obesity impairs brain neuroplasticity, increasing the risk for dementia and cognitive decline.
Having obesity increases a person’s risk for developing many chronic diseases, including dementia. The global prevalence of obesity is approximately 13 percent. A recent study suggests that obesity impairs brain neuroplasticity.
Neuroplasticity, the brain’s capacity to reorganize itself in response to changes in its environment, is critical during periods of learning, psychological stress, and trauma. Some evidence suggests that obesity impairs neuroplasticity. People with dementia and Alzheimer’s disease often have impaired neuroplasticity.
The study involved 30 young adults, 14 of whom had obesity and 16 of whom had healthy body weights. The authors of the study measured the participants' brain plasticity using a technique called theta burst transcranial magnetic stimulation (cTBS) – a procedure involving repeated pulses of electrical stimulation. They applied cTBS to the motor cortex of the participants' brains (an area responsible for the planning, control, and execution of voluntary movements) to briefly suppress excitability, a nerve’s capacity to produce an action potential.
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They found that cTBS suppressed cortical excitability in the participants in the healthy weight group but not among those in the obese group, suggesting impaired neuroplasticity among those with obesity.
The authors of the study suggested that the reduced neuroplasticity observed among the obese participants might be due to inflammation, a common feature in obesity and a key driver in many chronic diseases. However, they also posited that the impairments were due to reduced levels of brain-derived neurotrophic factor (BDNF) – a cell signaling protein that plays key roles in a number of signaling pathways. BDNF levels and signaling are often decreased in the setting of obesity, but exercise increases BDNF levels.