A Loop from Brain Function to Obesity and Back

Brain function can play a role in the development of obesity. And in turn obesity can play a role in brain function. Many knowledge gaps remain, but fascinating insights keep coming. And dopamine – an important neurotransmitter – seems to lie at the heart of changes in the brain linked to obesity. More and more research links dopamine signaling to the onset of obesity. Dopamine signaling also seems to be linked to declines in brain function linked to obesity and type 2 diabetes.

Linking Altered Dopamine Signals to Obesity

A growing body of research suggests that dopamine signals in the brain play a key role in susceptibility to obesity. Dopamine acts in the brain, regulating responses to food and food cues.

But dopamine signaling and the brain’s response to food is altered in people with obesity. Food cues – sights and smells – produce a stronger response. But actually consuming the food seems to produce less pleasure. Jen Guo and colleagues described this pattern in a 2014 paper in Molecular Psychiatry. More recently, Nils Kromer and Dana Small reviewed the available evidence and suggested that some of these changes may reflect alterations in learning about the rewards of highly caloric foods.

Linking Obesity and Diabetes to Cognitive Impairment

At the same time, brain science researchers find growing evidence to link obesity and diabetes with dementia and declines in brain function. They are working to understand what causes these declines. Is it diet, obesity, or diabetes? It could be a function of all three, plus other factors.

But what’s increasingly clear is that changes in dopamine signaling might be a common pathway for these cognitive impairments.

So we see a bit of a loop, where cause and effect are unclear. Altered dopamine signaling may be the basis for responses to food that contribute to obesity and diabetes. And in turn, diabetes and obesity may lead to changes in dopamine signaling and, ultimately, a decline in brain function.

Obesity is a bit more complex than some quaint popular notions might suggest.

Click here for a new review of dopamine and neurocognitive impairment in diabetes and obesity by Dana Small.

Loop, photograph © maldoit / flickr

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March 31, 2017