Do your genes make you lazy?


Do your genes make you lazy?

Do your genes make you lazy?

Obesity levels in the UK have been steadily increasing for the past eight years. In 2011 the proportion of adults with a healthy body mass index (BMI) was just 34% in men and 39% in women, but could there be a genetic reason for this rise?

Scientists may have identified a mutated gene that encourages you to exercise less and gain weight. This so called ‘couch potato’ gene was identified in mice and causes a desire to eat more and move less.

The gene affected the mice’s ability to produce and regulate dopamine signalling in the brain. This was shown to have the surprising effect of sudden weight gain, despite the fact that the affected mice ate the same amount as their unaffected cage mates. This could well be the first documented example of ‘unexplained’ weight gain that hasn’t been linked to a disorder. The mice with the mutated gene went on to develop symptoms similar to a human condition known as ‘metabolic syndrome’, something that usually happens as a result of diabetes or high blood pressure.

The affected dopamine receptors – which can normally pass through cell membranes – were found to accumulate within brain cells instead of being transported to the cell surface where they normally function. The transmission of dopamine has been proven to affect the bodies’ physical activity levels; hence this ‘build-up’ has a negative impact on the host’s motivation to live an active lifestyle. To combat this, researchers injected both groups of mice with a drug to stimulate inactive dopamine receptors, causing the mice with the mutated gene to become more active and lose significantly more weight than the normal mice: 13% compared to 7%.

This discovery could revolutionise treatments for obesity and obesity-related metabolic syndrome. However, it is not yet known how prevalent the mutated gene is in humans, or what affect the dopamine drugs used in the mice-study would have on humans.

Co-author Professor John Speakman from the University of Aberdeen is hopeful for the future. There are a significant number of people worldwide that have metabolic syndrome and it greatly impacts their day to day life. Even though these mutations are ‘rare’ in humans, he commented that “the population of sufferers that may benefit from being treated with dopamine receptor drugs runs into many millions of patients”.

The Overseas Development Institute has recently announced that one in three people worldwide are now overweight, with 64% of adults in the UK being classified as overweight or obese. Therefore, any possible treatment for obesity would have a massively positive impact on our society.

For more information about the genetic tests which can help you lose weight, check out ‘DNAFit’ and ‘BioClinics’ in our health listings.

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