New Study Found The Obesity Gene is not the only Thing to Blame.

A McGill-led research team has recently discovered that for girls who have a particular gene variant (DRD4 VNTR with 7 repeats), the crucial element that influences a fat intake, are more likely to suffer from obesity if they come from a lower income family.


A McGill-led research team has recently discovered that for girls who have a particular gene variant (DRD4 VNTR with 7 repeats), the crucial element that influences a fat intake, are more likely to suffer from obesity if they come from a lower income family. Interestingly, boys who had the same gene variant were not affected in the same way.


“The Study found that among girls raised in poorer families, those with DRD4 repeat 7 had a higher fat intake than other girls from the same socio-economic background,” says Laurette Dubé, the lead researcher on the study and Scientific Director of the McGill Centre for the Convergence of Health and Economics. “But, the study also found that girls with exactly the same gene variant who came from wealthier families, compared to these with the same economic conditions, had a lower fat intake. This suggests that it’s not the gene acting by itself, but rather how the gene makes an individual more sensitive to environmental conditions that determine “for better or worse” a child’s preference for fat and consequent obesity as the years pass by.”


200 young Canadian children used food diaries kept by the parents. The Parents calculated the percentages of fat, protein and carbohydrates the children were taking in. The BMI of the children were measured, and saliva tests were used to identify which of the children carried the DRD4 repeat 7 gene. The family income was calculated as a way of measuring the quality of the socio-economic environment in which the children were being raised.


” It was suggested that if the higher fat intake already reported by us in 7-repeat girls could be modified by the social environment — and the study showed that it can, as the fat intake will increase or decrease in 7-repeat girls according to their socio-economic status,” said Dr. Patricia Silveira, based in the Faculty of Medicine at the Universidade Federal do Rio Grande do Sul in Brazil, the first author on the study done in collaboration with McGill, University of Toronto and McMaster University. “This is important because to change the focus from the gene (previously “blamed” for the risk for increased fat preference) to the environment, since the effects of the gene will vary according to the conditions in which the child is raised.”


“It was previously assumed that the 7-repeat variant caused weight gain in these patients by increasing the rewarding aspects of certain foods. These new results suggest a different way that the gene might affect food choices” says Dr. Robert Levitan. Levitan is a co-investigator on the project, leader for the childhood obesity program in the MAVAN cohort, and Senior Scientist at the Centre for Addiction and Mental Health (CAMH), has studied the DRD4 gene in various female adult overeater populations. Boys at the same age don’t show the same clear pattern of food preferences. Interestingly, the researchers found this effect to be true only in the girls that they tested. The study suggest that this may be because, from an evolutionary standpoint, it may have been more important for girls to be able to gain weight easily to adapt to adverse conditions in order to reproduce.


“All that can be said with certitude from this research is that the gene variant will influence food choices differently according to the environment, but it is not known how the gene is influencing food preferences,” said Silveira.


“These results underscore the importance of moving beyond a ‘one-size-fits-all’ approach to childhood obesity prevention,” said Dubé.”Society needs to move towards targeted approaches that focus on populations that are particularly vulnerable to both genetic and environmental factors: people who are biologically more vulnerable under adverse environments are likely to be more responsive to improvements in the child’s conditions.”


Childhood obesity is a national epidemic. Nearly 1 in 3 children (ages 2-19) in the United States is overweight or obese, putting them at risk for serious health problems. As parents, caregivers, brothers and sisters, leaders in schools, communities and healthcare, statistics show Americans are beginning to create a nation where the healthy choice is the easy choice.


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Release ID: 103817