‘Happy gene’ challenges perceptions about obesity


Researchers at the University have discovered new genetic evidence about why some people are happier than others.

McMaster scientists have uncovered evidence that the FTO gene – the major genetic contributor to obesity – is associated with an eight per cent reduction in the risk of depression. In other words, it’s not just an obesity gene but a “happy gene” as well. The research appeared in a study published Tuesday in the journal Molecular Psychiatry.

The study was conducted by senior author David Meyre, associate professor in clinical epidemiology and biostatistics and a Canada Research Chair in genetic epidemiology; along with first author Dr. Zena Samaan, assistant professor, Department of Psychiatry and Behavioural Neurosciences, and members of the Population Genomics Program, Population Health Research Institute.

“We set out to follow a different path, starting from the hypothesis that both depression and obesity deal with brain activity. We hypothesized that obesity genes may be linked to depression,” says Meyre.

The team investigated the genetic and psychiatric status of patients enrolled in the EpiDREAM study led by the Population Health Research Institute, which analyzed 17,200 DNA samples from participants in 21 countries. Their findings produced the first evidence that an FTO obesity gene is associated with protection against major depression, independent of its effect on body mass index. Depression is a common medical condition that affects up to one in five Canadians.

“The difference of eight per cent is modest, and it won’t make a big difference in the day-to-day care of patients,” Meyre says. “But, we have discovered a novel molecular basis for depression.”

In the past, scientific studies attempting to associate genes with depression have been “surprisingly unsuccessful,” Samaan says. The McMaster discovery challenges the common perception of a link between depression and obesity.

The research was publicized in the Daily Mail, Toronto Star, the New Zealand Herald and several other news outlets.