Friday, December 04, 2015
The aroma of a savoury platter is known to trigger hunger pangs among the most reluctant of eaters. Now, a new study has used food smells to show that obese children may find it difficult to stay away from food because they may have a different brain wiring.
The findings of the study were presented at the Radiological Society of North America's annual meeting in Chicago. The study protocol entailed magnetic resonance imaging (MRI) scan of the brains of 30 children aged 6-10 years, while they were exposed to distinct smells. The children were asked to smell two food items, namely chocolate and onion, and a non-food item, diluted acetone (a nail polish remover ingredient). Half of the children were obese [body mass index (BMI) >30 kg/ m2], while the remainder were healthy (BMI= 19–24 kg/ m2).
Interestingly, the researchers found that the food smells triggered opposite reactions among the heavy and normally weighted children. In the case of obese kids, the food odours activated the brain areas linked to impulsive behaviour and obsessive-compulsive disorder. The odour of onion or chocolate triggered activity in the portion of brain involved in impulsive decisions. However, no such activity was evident from the MRI scans of the brain areas that control the impulse to eat.
Contrastingly, when the healthy children smelt food, the researchers saw activity in parts of the brain responsible for regulating pleasure, planning and emotional processing or memory. The obese kids also showed much greater brain responses when they smelt the chocolate or onion compared to the healthy kids. When these kids smelt the acetone, the parts of their brain related to memories and risk assessment were activated. The healthy subjects appeared to show no interest in the acetone smell.
Dr. Pilar Dies-Suarez, head of radiology at the Federico Gomez Children's Hospital of Mexico in Mexico City said, “The findings suggest that children with obesity are not able to stop eating. Thus, treatment of obesity must focus on the impulsivity problem.”
However, this study is limited by several drawbacks. The study neither gives any information to show that the children could not control food cravings, nor does it inform about the feeding patterns of the obese kids. Moreover, the sample size is small, and the results are preliminary and merely hint a relationship between impulsive brain reactions and children's weight. Although the researchers are still unsure about a causative relationship, the study espoused that obese children may have different brain wiring.
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