Morbid obesity may have a deleterious effect on young, developing brains, according to researchers whose studies have revealed that obesity in toddlers is linked to lower IQ scores later in life.
The association of obesity with metabolic problems like diabetes, high cholesterol and hypertension is a well documented fact.
Dr. Daniel Driscoll, a professor of pediatric genetics at the University of Florida said, "We're postulating that early-onset morbid obesity and these metabolic, biochemical problems can also lead to cognitive impairment."
Driscoll and his colleagues conducted their studies on 18 children and adults with early-onset morbid obesity that is with a weight at least 150 per cent of their ideal body weight before age four.
The study has been published in the August issue of the Journal of Pediatrics. A second group of 19 children and adults with Prader-Willi syndrome which is a genetic disorder that causes people to eat non-stop and become morbidly obese at a young age if not supervised was also studied.
The control group consisted of 24 normal-weight siblings who shared the same genetic and socio-economic background as the research subjects.
It was found that children and teens who were obese as toddlers not for any known genetic reason fared as poorly on IQ tests with an average score of 78 as people with Prader-Willi with an average score of 63.
Driscoll said, "It was surprising to find that they had an average IQ score of 78, whereas their control siblings were 106."
"We feel this may be another complication of obesity that may not be reversible, so it's very important to watch what children eat even from a very young age. It's not just setting them up for problems later on; it could affect their learning potential now."
MRI brain scans revealed lesions in the white matter of several patients with Prader-Willi and early-onset morbid obesity.
Such lesions are typically found in adults with Alzheimer's disease or in children with untreated phenylketonuria.
Driscoll said that these lesions are probably a result of metabolic changes in the young brain, adding that obesity later in life did not carry the risk for cognitive impairments because their brains are developed enough to fend off the damage.