LONDON — It is bad for your blood pressure, knocks years off your life and is a strain on your heart. Now scientists have discovered that gaining weightlowers your intelligence.
A five-year study of more than 2,200 adults claims to have found a link between obesity and the decline in a person’s cognitive function.
The research, conducted by French scientists, was published for the first time this month in Neurology journal. It involved men and women between 32 and 62 years of age who took four mental-ability tests, then repeated them five years later.
The researchers found that people with a body mass index — a measure of body fat — of 20 or less could recall 56 percent of words in a vocabulary test, but those who were obese, with a BMI of 30 or higher, could remember only 44 percent.
The fatter subjects also showed a higher rate of cognitive decline when they were retested five years later: Their recall dropped to 37.5 percent, but those with a healthy weight retained their level of recall.
To explain the reduced cognitive powers, Maxime Cournot, who headed the study, suggested that hormones secreted from fats could have a damaging effect on cerebral cells, resulting in less brain function.
“Another explanation could be that since obesity is a widely known cardiovascular risk factor, due to the thickening and hardening of the blood vessels, that the same happens with the arteries in the brain,” said Dr. Cournot, an assistant professor in clinical epidemiology at Toulouse University Hospital.
“It would be logical that losing weight would make your cognitive function increase,” she added.
David Haslam, the clinical director of the National Obesity Forum, established in 2000 to raise awareness of the health implications of being overweight, said the new research was “alarming.”
“It goes to show obesity affects every single organ in the human body,” he said. “No one wants to be obese, especially when it causes dementia and heart disease, but the news that it affects your brainpower will come as a shock and is alarming.”
But Anne Widdecombe, a former British Cabinet minister who lost 30 pounds participating in a television show called “Celebrity Fit Club,” said she was skeptical of the study.
“You just need to look around the world, and you will see hundreds of thin nitwits and clever fat people,” she said.