Brain function differs in obese children, study shows

Diet and exercise may not be enough to restore normal weight or prevent overweight children from becoming obese, they conclude. It may be necessary to change their brain function.

In a paper published in the journal Heliyon, the researchers suggest that mindfulness, a practice used as a therapeutic technique to focus awareness, should be studied as a way to encourage healthy eating and weight loss in children.

"Adults, and especially children, are primed towards eating more," said senior author Kevin Niswender, M.D., Ph.D. "This is great from an evolutionary perspective ... but in today's world, full of readily available, highly advertised, energy dense foods, it is putting children at risk of obesity."

"We think mindfulness could recalibrate the imbalance in the brain connections associated with childhood obesity," added co-senior author Ronald Cowan, M.D., Ph.D. "Mindfulness has produced mixed results in adults ... So far there have been few studies showing its effectiveness for weight loss in children."

Childhood obesity in the United States has nearly doubled during the past 30 years, and among adolescents it has tripled. In 2010, a third of U.S. children were considered obese or overweight.

The Vanderbilt study included 38 children, five who were considered obese and six who were overweight. Their eating behaviors were assessed using a questionnaire, and their brain function was assessed using magnetic resonance imaging (MRI).

Three brain regions in adults are potent modulators of eating habits: the nucleus accumbens, associated with reward-motivated behaviors; the frontal pole, associated with impulsivity; and the inferior parietal lobe (IPL), associated with response inhibition, the ability to inhibit or override a response such as overeating.

The researchers used MRI to determine the balance of functional neural connectivity between these eating-related brain regions in children of various weights.

"We wanted to look at the way (their) brains function in more detail so we can better understand what is happening neurologically in children who are overweight and obese," said first author and Vanderbilt graduate student BettyAnn Chodkowski.

They found that as weight increased among children, the connectivity between the inhibition-associated IPL and reward-associated nucleus accumbens decreased, while connectivity between the nucleus accumbens and the impulsivity-associated frontal pole increased.

This suggests that unhealthy eating behaviors and obesity could reflect an imbalance in the functional connectivity of brain areas associated with response inhibition, impulsivity and reward.

The practice of mindfulness can increase response inhibition and decrease impulsivity. Mindfulness has been used to encourage healthy responses to everyday adversities, although few studies have tested its use in the area of healthy eating or weight loss among children.

Among adults, mindfulness has had mixed results when used for weight loss and weight control, which may reflect "the extreme tenaciousness of adult obesity," as well as age-related loss of brain plasticity, the researchers noted.

This supports the importance of early identification of children at risk for obesity, and the need to develop novel methods to treat and prevent it, they concluded.