I am one of those people that cannot say no to a burger. Or a chocolate bar. In fact, the healthier the snack, the lesser I am attracted to it. It is almost as if I have a predisposition towards high calorie foods rich in sugar as well as fats. This phenomenon has been the focus of a recent research conducted by Dr. Tony Goldstone, who has undertaken to find out if the genes of an individual affect an individual’s food choices.
Dr. Tony Goldstone’s Study
Dr. Tony Goldstone, together with his colleagues from Imperial College in London, UK, carried out a study using 45 white European participants of body mass index starting from 19.1 kg/m2 (normal weight) to 53.1 kg/m2 (super obese) and within the 19-55 year age bracket. The DNA of the participants was mapped out and the variants near the Fat Mass and Obesity-associated protein gene (FTO gene) and the Dopamine Receptor D2 gene (DRD2 gene) were determined. The participants were then shown pictures of foods high and low in calories, asked to rate them, and the researchers, using functional magnetic resonance imaging scanned the brain activity of the participants after visualization of the different calorie foods.
How does this FTO gene and DRD2 gene cause obesity?
Variants near the FTO gene found on chromosome 16 predispose an individual to obesity. This is because these variations result in an increase in the blood levels of ghrelin, also known as the hunger hormone. As a result, an individual has an elevated urge to eat, even after feeding. The variations are also associated with an altered response to ghrelin as well as food images.
The researchers also discovered that those with the variants near the FTO gene perceived foods high in calories as more enticing compared to foods low in calories, and showed increased orbitofrontal cortex activity.
Variants near the DRD2 gene increased the striatum activity, and this caused an increase in the cravings for foods high in calories, due to increased release of dopamine signals. The result of increased levels of ghrelin, increased perception of high calorie foods as enticing and the increased craving for these foods is the predisposition to obesity.
The Possibility of Individualised Obesity Therapy.Approximately
79 million adults in the US are obese. This figure represents more than one third of adults living in the US. With obesity comes a number of complications such as, non-insulin dependent diabetes mellitus, heart disease, some cancers and stroke. While the combination of exercise and proper dietary therapy has been used as the mainstay treatment of therapy, factors such as the variants in the FTO gene and DRD2 gene can hinder appropriate response to these therapies, especially dietary therapy.
As such, more individualized therapies have been suggested for these patients, such as use of gut hormones that act on the dopamine cells within the central nervous system to reduce the cravings for foods high in calories resulting from the altered dopamine production.