Although it is natural for our brains to shrink with age, this process can also be affected by obesity, which can act as a catalyst to the onset and progression of brain aging, say scientists.
New research from the University of Cambridge, UK, has found that from middle age, the brains of those who are obese show differences in white matter similar to those seen in slimmer individuals who are ten years older.
To investigate further the team of researchers carried out a cross-sectional study — a study which analyses data from individuals at one point in time — using 473 participants between the ages of 20 and 87.
Of the participants, 246 (51%) were defined as lean, with a Body Mass Index (BMI) between 18.5 and 25(kg/m2), 150 (31%) were overweight with a BMI between 25 and 30 (kg/m2), and the remaining 77 were classed as obese with a BMI great than 30(kg/m2).
Individuals were then divided into two groups, lean and overweight, and MRI scans were taken to look at brain volume. Participants’ cognitive abilities were also tested.
The team first found that the brains in the two groups showed significant differences in the volume of white matter — the tissue that connects areas of the brain and enables communication between different regions — with those in the overweight group showing a large reduction in white matter compared to those in the lean group.
When the researchers looked at how the volume of white matter related to age, they also found that an overweight person in middle-age, for example at 50 years old, showed a volume of white matter similar to a lean person aged 60 years, suggesting a difference in brain age of 10 years.
As these differences were only seen from middle-age onwards, the results imply that brains may be particularly vulnerable during this particular period of ageing.
However despite the differences in the volume of white matter between the two groups, there was no association between being overweight or obese and an individual’s cognitive abilities.
Although the researchers commented that they cannot conclude that obesity is causing the brain changes, or whether obesity may even be a consequence of brain changes, senior author Professor Paul Fletcher commented that, “We’re living in an aging population, with increasing levels of obesity, so it’s essential that we establish how these two factors might interact, since the consequences for health are potentially serious.’
“It will also be important to find out whether these changes could be reversible with weight loss, which may well be the case,” he added.
The study can be found online published in the journal Neurobiology of Aging.
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