Food for thought: Obese and overweight children have less developed brains

Overweight children could struggle at school because piling on the pounds affects their brain health, a study suggests.

Researchers have discovered that a higher weight and BMI in children could influence key areas of the brain’s connectivity.

This could affect attention span and the ability to juggle multiple tasks, they warned.

The team, from the Yale School of Medicine in Connecticut, analyzed brain imaging data for 5,169 children aged between nine and 10-years-old.

They specifically looked at connectivity between the neural regions and how much white matter was present, which is important for communication between different areas of the brain.

This was then compared to the children’s BMI z-scores, a measure of weight adjusted for a child’s age and sex.

It comes after a study found eating junk food can trigger aches or make people more sensitive to pain — even if they are healthy and slim, a study suggests.

Results from the latest study revealed there were structural changes in the brains of children who had a higher weight and BMI, including ‘significant impairment’ to the white matter.

Some of the areas most affected included the white matter of the corpus callosum – a large bundle of more than 200 million nerve fibers that connect both sides of the brain.

The scientists also observed a thinning of the outer layer of the brain which has been associated with impaired executive function, for example being able to plan, focus attention, remember and juggle multiple tasks.

Researcher Simone Kaltenhauser said it is known that being obese is associated with poor brain health in adults, but previous studies on children have often focused on small populations or single aspects of brain functioning.

‘It is striking that these changes were visible early on during childhood,’ she said.

‘Increased BMI and weight are not only associated with physical health consequences but also with brain health.

‘Our study showed that higher weight and BMI z-scores in nine and 10-year-olds was associated with changes in macrostructures, microstructures and functional connectivity that worsened brain health.’

Senior author Sam Payabvash, an assistant professor of radiology and biomedical imaging, said the study’s findings provide an important mechanistic explanation of other research that shows higher BMI in children is associated with poor cognitive functioning and school performance.

A previous study has found that girls who are obese at the age of 11 get lower exam grades as they move through school.

One of the most comprehensive studies to examine the link between obesity and academic attainment found girls’ grades fell in core subjects over five years if they were overweight.

The research, by Dundee, Strathclyde, Georgia and Bristol universities, found that girls who were obese at the age of 11 continued to have lower achievement levels at 13 and 16.

The scientists said poor mental health and the stigma linked with being overweight could be a cause of the trend.

But Dr Josie Booth, author of the study, said at the time: ‘Other research suggests that there is a biological impact which could lead to poorer performance, but we can’t answer that with this study.’

Another study, carried out in China in 2017, found childhood obesity was associated with poor academic performance, and that this was partially due to obese children having poor short-term memory skills.

The current findings were presented at the annual meeting of the Radiological Society of North America in Chicago.