In a UK study on children’s food intake and energy use, researchers found that those carrying a variant of a gene known to be linked to obesity, ate an average of 100 extra calories per meal suggesting the gene influenced food intake and choice.
The study was the work of corresponding author Dr Colin Palmer of the Biomedical Research Institute, Ninewells Hospital and Medical School, University of Dundee, Scotland, and colleagues from other universities in Scotland and England, and is published online on 11 December in the New England Journal of Medicine, NEJM.
When they compared the food intake of children carrying a particular variant of an obesity-linked gene called FTO to children who did not have that variant, Palmer and colleagues found that while they ate the same weight of food, their energy intake was higher, regardless of their own body weight, suggesting that the children with the gene variant were choosing to eat food richer in calories. This led them to suggest that perhaps the FTO variant was evidence of a “hyperphagic phenotype”, a genetic make up that makes people to eat too much.
Several studies have shown strong links between variants of the FTO gene and obesity but how it affects energy use and food intake is not so clear.
For this study, Palmer and colleagues studied 2,726 Scottish children aged from 4 to 10 with known height and weight and who had had tests to see if they had a particular variant of the FTO gene known as rs9939609. They also studied a small subset of the children, 97 in all, and measured their food intake, body fat, and energy use and looked for links between those variables and the FTO variant.
The results showed that:
- In the large group and the subsample, the FTO variant was linked to increased weight and body mass index (BMI, weight in kilos divided by the square of the height in metres).
- In the subsample, the FTO variant was linked to increased body fat but not lean mass.
- Although total and resting energy use was higher in children with the FTO variant, resting energy use was in line with that expected for their age and weight, suggesting that those carrying the gene variant did not metabolize food differently.
- The FTO variant was linked to higher energy intake independently of body weight.
- But children with the FTO variant ate the same weight of food as children who did not have it.
The authors concluded that:
“The FTO variant that confers a predisposition to obesity does not appear to be involved in the regulation of energy expenditure but may have a role in the control of food intake and food choice, suggesting a link to a hyperphagic phenotype [people genetically predisposed to over-eating] or a preference for energy-dense foods.”
“An Obesity-Associated FTO Gene Variant and Increased Energy Intake in Children.”
Cecil, Joanne E., Tavendale, Roger, Watt, Peter, Hetherington, Marion M., Palmer, Colin N.A.
N Engl J Med, Volume 359, Number 24, pp 2558-2566, published online 11 December 2008.
Sources: Journal Abstract.
Written by: Catharine Paddock, PhD