Obesity messes with the brain
Memory and concentration diminish as organ's wiring sustains damage
By Janet Raloff
Obesity subtly diminishes memory and other features of thinking and reasoning even among seemingly healthy people, an international team of scientists reports. At least some of these impairments appear reversible through weight loss. Researchers also report one likely mechanism for those cognitive deficits: damage to the wiring that links the brain’s information-processing regions.
A number of studies in recent years have shown that individuals with diseases linked to obesity, including cardiovascular disease, hypertension and type 2 diabetes, don’t score as well on cognitive tests as less hefty individuals do. To test whether weight alone — and not disease — might be partially responsible, John Gunstad of Kent State University in Ohio and his colleagues recruited 150 obese individuals for a series of cognitive tests. These people weighed on average just under 300 pounds, although some were substantially heavier. Two-thirds would shortly undergo weight-loss surgery.
Scores on the tests were assessed against those of people in the Brain Resource International Database, a large multicenter project with data on very healthy people. Obese individuals in the new study initially performed on the low end of the normal range for healthy individuals from the database on average, Gunstad says, although nearly one-quarter of the obese participants’ scores on memory and learning actually fell within what researchers consider the impaired range.
Tested again 12 weeks after bariatric surgery — when most had shed some 50 pounds — the lighter but still heavy patients scored substantially better. Most now performed “within the average or greater-than-average range for all cognitive tests,” the researchers reported online in October in Surgery for Obesity and Related Diseases.