Packing on the pounds may increase your body mass index, but it won't increase brain volume, according to a new MRI study. Although the human brain inevitably shrinks as it ages, researchers have found that the brains of obese subjects appear 10 years older at middle age than their fitter counterparts.
The UK study, entitled Obesity associated with increased brain-age from mid-life, and published in the journal Neurobiology of Aging, scanned the brains of 473 participants. Using BMI as classification, 246
of the participants were lean, 150 were overweight and 77 were obese. The subjects were divided into two groups (lean and overweight) to have their cognitive abilities tested and their brains scanned.
The researchers noticed that the volume of white matter (the region of the brain responsible for communication between various brain networks) in the overweight group was significantly less than the lean subjects. Furthermore, brain scans of 50 year-old obese subjects resembled scans of 60 year-old lean subjects.
Lead author of the study, Professor Paul Fletcher of the University of Cambridge, said, "We're living in an aging population, with increasing levels of obesity, so it's essential that we establish how these two factors [white matter and obesity] might interact, since the consequences for health are potentially serious."
At this point, the researchers can't say whether obesity is a consequence of changes to white matter, or if it's the other way around.