How this gene variant influences what we eat

Washington D.C.: Hate the taste of broccoli? Do you perceive honey as too sweet? According to a new study, a common gene variant should be blamed for our food choices.

The McGill-led research team has recently discovered that for girls who are carriers of a particular gene variant (DRD4 VNTR with 7 repeats), the crucial element that influences a child's fat intake is not the gene variant itself.

Instead, it is the interplay between the gene and girls' early socio-economic environment that may determine whether they have increased fat intake OR healthier than average eating compared to their peers from the same class background. The DRD4 repeat 7 is found in approximately 20 per cent of the population and is known to be associated with obesity, especially in women.

Lead researcher Laurette Dube said that they 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, but they 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.

Dube noted that 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 determines "for better or worse" a child's preference for fat and consequent obesity as the years pass by.

Interestingly, the researchers found this effect to be true only in the girls that they tested. They speculate 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.

Another possibility they advance is that at age four, it may simply be too early to see these effects in boys since boys and girls gain weight at different stages at this age, and may also have different behavioural responses to hunger and feelings of satiety.

These results underscore the importance of moving beyond a 'one-size-fits-all' approach to childhood obesity prevention, said Dube, adding "we need to move towards targeted approaches that focus on populations that are particularly vulnerable to both genetic and environmental factors: those who are biologically more vulnerable under adverse environments are those likely to be more responsive to improvements in their conditions."

The study appears in JAMA Pediatrics.