The brains of overweight and obese people display images of white matter similar to those found in brains of leaner people ten years older, a new University of Cambridge research study titled “Obesity associated with increased brain-age from mid-life,” recently published in Neurobiology of Aging.
The report suggests that the brains of obese middle age people are ten years older than leaner people in the same age category.
Lisa Ronan, PhD, first author of the study, led the research team that studied 473 people, ages 20 – 87, at the Cambridge Centre for Aging and Neuroscience, to study the impact of obesity on the brain structure of adults and to determine whether obesity can be linked to brain changes typical in the aging process.
Individuals were divided into two categories by weight; lean and overweight.
Striking differences were found in the volume of white matter in the brains – overweight people had bigger widespread reduction in white matter. White matter is the brain tissue that connects areas of the brain and allows information to flow between regions. Human brains begin to shrink at about middle age, but because of the recent findings investigators now believe that obesity may speed the onset and progression of brain aging.
The team then calculated how white matter volume was related to age across the two groups. In one example, an overweight 50 year-old had a comparable white matter volume to a lean 60 year-old, implying an average difference in brain age of up to a decade.
“As our brains age, they naturally shrink in size, but it isn’t clear why people who are overweight have a greater reduction in the amount of white matter,” said Ronan, of the Department of Psychiatry at the University of Cambridge, in a press release. “We can only speculate on whether obesity might in some way cause these changes or whether obesity is a consequence of brain changes.”
The differences were observed only from middle-age onward.
Paul Fletcher, the study’s senior author and professor at Cambridge’s Department of Psychiatry said the consequences for health, in an aging society with increasing rise in obesity, is potentially a serious matter.
“The fact that we only saw these differences from middle-age onwards raises the possibility that we may be particularly vulnerable at this age. It will also be important to find out whether these changes could be reversible with weight loss, which may well be the case,” Fletcher said.
No connection was made between the difference in brain white matter and cognitive abilities, as so far measured by standard IQ tests.
“We don’t yet know the implications of these changes in brain structure. Clearly, this must be a starting point for us to explore in more depth the effects of weight, diet and exercise on the brain and memory,” said co-author Sadaf Farooqi, a professor at the Wellcome Trust-Medical Research Council Institute of Metabolic Science at Cambridge.