Losing It Can be Good for the Brain
A map of the United States prepared by the Centers for Disease Control (CDC) includes a color key: blue for states where less than 20 percent of the inhabitants are obese, and red or tan for states whose obese population exceeds 20 percent.
There are no blue states on the map. Nearly 36 percent of U.S. adults, and 30 percent of people in Ohio, are obese, reports the CDC, which calls obesity “common, serious and costly.”
The causes and health effects of obesity are being scrutinized closely as excessive weight gain has emerged as a major public health issue. A Kent State University researcher is studying the problem from a slightly different angle – if obesity is bad for the heart and liver, can it also be bad for the brain?
It has long been known that the more obese you are, the more you are at risk for getting Alzheimer’s disease or other types of neurological disorders, noted John Gunstad, Ph.D., associate professor in the Department of Psychology whose research specialty is neuropsychology and health.
That fact led him to wonder, “If excess weight causes memory problems, can losing significant weight have the opposite effect?”
Feeling sharp, thinking clearlyIn a study spanning more than four years, Gunstad followed 125 patients who had bariatric surgery, resulting in sudden weight loss, and a control group of patients who did not.
“The primary motivation for looking at surgery patients is that we know they lose a lot of weight in a short amount of time, so it was a good group to study,” he said.
At the start of the experiment, a quarter of those undergoing surgery had meaningful impairments in memory or other mental abilities. Three years after surgery, only 4 percent did.
Improvements were particularly noteworthy on tests of memory and executive functioning in the patients who had the surgery. Executive functioning is a complex set of mental abilities that include problem solving, planning and organizing behavior.
“This is the first evidence to show that by going through this surgery, individuals might improve their memory, concentration and problem solving,” said Gunstad.
Gunstad was not surprised at the study’s results. “A lot of the factors that come with obesity – such as high blood pressure, type 2 diabetes and sleep apnea – that might damage the brain are somewhat reversible. As those problems go away, memory function gets better.”
While tests showed that, patients noticed a difference, too. After losing weight, “patients often report they feel sharper, they have greater clarity,” Gunstad said.
Most of those who had the surgery kept the weight off. But patients who re-gained weight started to show some of the memory impairments that existed before surgery.
The link to Alzheimer’sThe research was funded by a $1.5 million grant from the National Institutes of Health. Gunstad was the principal investigator on a team that included researchers from Cornell Medical College and Weill Columbia University Medical Center in New York City; the Warren Alpert Medical School of Brown University, Providence, R.I.; the University of Missouri-St. Louis and the Neuropsychiatric Research Institute in Fargo, N.D.
Last fall he was the only university researcher to speak at the Cleveland Clinic’s annual Medical Innovation Summit; he talked about his findings in a panel discussion on “Diet, Obesity and Alzheimer’s Disease.” Another panelist, Jeff Cummings, M.D., director of the Cleveland Clinic’s Lou Ruvo Center for Brain Health, said that Alzheimer’s disease has been called “type 3 diabetes” by some because of its strong link to obesity. About half of the risk for the disease is linked to age and genetics, he noted, but the other half is linked to areas that are at least partly controllable.
“You can reduce your risk with lifestyle modification,” he said.
As Gunstad said, “One of the things about obesity, relative to some other medical conditions, is that something can be done to fix it.”
Older patients, those most at risk for Alzheimer’s disease, were once thought to be ineligible for bariatric surgery. But improvements to the procedure have increased the age limit on its use. He now wants to examine whether older bariatric patients show the same improvements in memory and other mental abilities as younger patients and clarify whether bariatric procedures might reduce the risk of Alzheimer’s disease over time. Data from a pilot study suggest they can, he said.
“One of the things we know is that as individuals’ heart health gets better, their brain health also improves.”
About the ResearcherJohn Gunstad earned his Ph.D. in clinical psychology at Ohio University in 2002. He was a postdoctoral fellow and an intern in clinical neuropsychology at Brown University Medical School.
He received an Early Career Research Award from the International Neuropsychological Society and awards for teaching and research from Kent State.
His research areas are the effects of aging and disease on neurocognitive function, with a particular interest in cardiovascular disease and obesity.