A team of researchers based at the University of Aberdeen have uncovered a genetic ‘switch’ which they believe makes Europeans far more likely to opt for high-fat food and alcohol than those in Asia.
The study, published in the Journal of Neuropsychopharmocology, reported that European and Asian populations have differences in an important genetic switch – which controls the activation of the galanin gene – that regulates appetite and thirst.
The researchers, led by Dr Alasdair MacKenzie, said that the genetic ‘switch’ differed by groups of people from different regions. For example, they found the switch was mutated and weaker in 16 per cent of Europeans and 30 per cent of Asians.
“The switch controls the areas of the brain which allows us to select which foods we would like to eat and if it is turned on too strongly we are more likely to crave fatty foods and alcohol,” said Dr MacKenzie. “The fact that the weaker switch is found more frequently in Asians compared to Europeans suggests they are less inclined to select such options,” he added,
The researchers compared the DNA of humans to that of mice and birds, revealing a genetic switch, also known as an enhancer, which has remained unchanged for 300 million years.
The switch controls the galanin gene, which when turned on in an area of the brain called the hypothalamus, regulates appetite and thirst.
The team also noticed that the switch was different in some people and when they compared different racial groups they found that it had mutated and was weaker in 16 per cent of Europeans and 30 per cent of Asians.
The study does not, however, just explain rising obesity rates across the West, said MacKenzie, pointing to the possibility that the genetic difference is a survival mechanism that helped European ancestors in the winter months.
“These results give us a glimpse into early European life where brewing and dairy produce were important sources of calories during the winter months. Thus, a preference for food with a higher fat and alcohol content would have been important for survival,” said MacKenzie.
“It is possible that during the winter individuals with the weaker switch may not have survived as well in Europe as those with the stronger switch and as a result those in the west have evolved to favour a high fat and alcohol rich diet,” he added.
Source: Journal of Neuropsychopharmocology
Published online ahead of print, doi: 10.1038/npp.2011.93
“Differential Activity by Polymorphic Variants of a Remote Enhancer that Supports Galanin Expression in the Hypothalamus and Amygdala: Implications for Obesity, Depression and Alcoholism”
Authors: S. Davidson, M. Lear, L. Shanley, B. Hing, et al