Obesity Linked to Impaired Brain Function in Adolescents
A new study links obesity and metabolic syndrome (MetS) with cognitive and brain impairments in adolescents.
Researchers at New York University School of Medicine say pediatricians should take their findings into account when considering the treatment of childhood obesity.
As childhood obesity has increased in the U.S., so has the prevalence of metabolic syndrome, a constellation of three or more of five health problems, including abdominal obesity, low HDL (good cholesterol), high triglycerides, high blood pressure and pre-diabetic insulin resistance.
Lead investigator Dr. Antonio Convit, a professor of psychiatry and medicine at NYU School of Medicine, and his colleagues have previously linked metabolic syndrome to neurocognitive impairments in adults, but this association was generally thought to be a long-term effect of poor metabolism. Now, the research team has revealed even worse brain impairments in adolescents with metabolic syndrome.
“The prevalence of MetS parallels the rise in childhood obesity,” Convit said. “There are huge numbers of people out there who have problems with their weight. If those problems persist long enough, they will lead to the development of MetS and diabetes. As yet, there has been very little information available about what happens to the brain in the setting of obesity and MetS and before diabetes onset in children.”
For the study, researchers compared 49 adolescents with metabolic syndrome to 62 teens without the disorder. Of those who were not in the MetS group, 40 percent were considered overweight or obese, so while they were not in ideal health, they did not have three out of the five health issues needed to fall into the MetS group.
The research team balanced each group according to age, socioeconomic status, school grade, gender and ethnicity to ensure things like cultural differences in diet and access to quality healthcare did not cloud the data. They then conducted endocrine, MRI, and neuropsychological evaluations on the adolescents and found that those classified as having MetS showed significantly lower math and spelling scores, as well as decreased attention span and mental flexibility.
They also showed differences in brain structure and volume, presenting with smaller hippocampal volumes, which is involved in the learning and recall of new information; increased brain cerebrospinal fluid; and reductions of microstructural integrity in major white matter tracts in the brain. The more MetS health problems the participants had, the more profound the effect across the board, according to the researchers.
“The kids with MetS took longer to do tasks, could not read as well and had poorer math scores,” Convit said. “These findings indicate that kids with MetS do not perform well on things that are very relevant to school performance.”
The researchers concluded that even a few years of problems with metabolism may cause brain complications. They suggest the adverse impact of MetS on brain function in children could be used by pediatricians as a powerful motivator to get families more involved in meaningful lifestyle change.
“Only now are pediatricians becoming aware of some of these issues,” Convit said. “Many pediatricians don’t even take a blood pressure, and they certainly are not taking cholesterol levels and testing insulin resistance.”
He added that about one third of children who are obese have abnormal cholesterol levels and more than 40 percent of those who are really obese have insulin resistance.
“Obesity in kids is sky high,” he said. “Nearly 40 percent of the U.S. population is considered obese. Parents need to understand that obesity has medical consequences, even in children, and some of those consequences may be impacting more than just the long term health of the cardiovascular system. We need to do what our grandmothers have told us all along: ‘Eat well, don’t overeat and try to move as much as possible.'”
Convit added that simple changes in daily routine, such as walking more or taking the stairs, would go a long way in preventing MetS. Future research is needed to determine whether the reductions in cognitive performance and structural brain abnormalities are reversible with significant weight loss, he added.
“The take home message is that just being overweight and obese is already impacting your brain,” Convit said. “Kids who are struggling with their weight and moving toward having MetS may have lower grades, which could ultimately lead to lower professional achievement in the long run.”
“These are run-of-the-mill, garden-variety kids, not kids that came into the hospital because they were sick. It is imperative that we take obesity and physical activity seriously in children. In this country, we’re taking away gym class in order to give children more class time in an effort to improve school performance, but that effort may be having the exact opposite effect.”
The study, funded by the National Institutes of Health, appeared online in Pediatrics.
Wood, J. (2012). Obesity Linked to Impaired Brain Function in Adolescents. Psych Central. Retrieved on April 21, 2015, from http://psychcentral.com/news/2012/09/08/obesity-linked-to-impaired-brain-function-in-adolescents/44318.html