Along with a risk of hypertension, heart disease and diabetes, scientists have come up with another reason to avoid obesity: Brain shrinkage.
A UCLA study released Tuesday shows the brains of obese older adults are on average 8 percent smaller than their more fit counterparts.
“If you can do anything about obesity, know that you are not only saving your waistline, but saving the life of your brain,” said Paul Thompson, senior author of the study and a professor of neurology at UCLA.
The study is the first time researchers have linked neurological illnesses such as dementia with obesity, which is normally associated with an increased risk of heart attack and stroke.
Thompson, along with Cyrus Raji of the University of Pittsburgh School of Medicine, compared brain scans of 94 people in their 70s as part of a larger study looking at the causes brain damage.
The researchers were surprised when they broke the group down by Body Mass Index, finding a sharp contrast in brain decline among those who were normal weight, overweight and obese.
Those who were overweight had an average decline of 4 percent, showing brain loss in the basal ganglia, which regulates motor skills and learning; the corona radiata, or white matter composed of axons that carry neural traffic throughout the brain; and the parietal lobe, which regulates a number of sensory functions such as navigation and spacial sense.
Those who were obese had even more extensive loss in the frontal and temporal lobes, which are critical for planning and memory; in the anterior cingulate gyrus, which affects attention; the hippocampus, which controls long-term memory and the basal ganglia.
“This also applies to younger people,” said Thompson, a Redondo Beach resident. “When you take good care of yourself throughout your life, you feel better and you build up kind of a reserve in the brain. The good news is that this is something you can do something about.”
Ralph Ford, a retired school teacher in Redondo Beach who leads a fitness class for seniors, wasn’t surprised by the results.
“Exercise makes a big difference,” said Ford, 64. “You see it all the time. The ones who are consistent with weights and exercise have good posture, stay active and are more alert.”
Another piece of good news from the study: It appears the tissue loss is reversible – at least, to an extent. Five years after their initial scan, some of the study participants were able to reverse the tissue loss by up to
4 percent, Thompson said.
The percentages may seem small, but people would start to experience noticeable mental decline, such as memory loss and reduced motor skills, at 8 percent decline, researchers say. By comparison, people with Alzheimer’s disease have about 10 percent less brain mass than others.
“We all lose brain tissue as we age,” Thompson said. “But we find that the more effort you put into staying healthy and exercising, the less you experience decline.”
The research was funded by the National Institute on Aging, the National Institute of Biomedical Imaging and Bioengineering, the National Center for Research Resources and the American Heart Association.