There is yet another organ that experiences profound, and likely long-term, benefits from weight loss surgery: The brain.
The connection between body weight and brain function is well known. Overweight and obese people have a much higher likelihood of developing Alzheimer’s disease — about 35% higher — than normal weight people.
Though this relationship isn’t totally understood, researchers know, based on the new study, that it appears to be reversible. That is, when obese people lose weight, the adverse effects on the brain seem to reverse as well.
The team used PET scans to measure the metabolic activity in a group of women before and six months after weight-loss surgery. They also gave the women cognitive tests at the same time points to measure the women’s thinking abilities. Normal weight women served as controls.
Obesity may force the brain to work harder to achieve the same level of cognition.
Before the surgery, certain areas of the brains of the obese women used sugar at a higher rate than that of normal weight women. One of the regions affected was the posterior cingulate gyrus, known to be involved in the development of Alzheimer’s disease.
Six months after the surgery, the differences in sugar metabolism were no longer evident.
Women who had bariatric surgery also did better on tasks like planning and organizing after the surgery than they had done before it. Other mental functions, including memory, did not show a difference.
Increased metabolic activity in the brain before the surgery wasn’t correlated with better performance on the tests — performance only improved after the surgery, the Brazilian researchers point out.
“Our findings suggest the brain is another organ that benefits from weight loss induced by surgery,” said study author Cintia Cercato in a statement. “The increased brain activity the obese women exhibited before undergoing surgery did not result in improved cognitive performance, which suggests obesity may force the brain to work harder to achieve the same level of cognition.”
The authors are hopeful that weight-loss surgery might have significant effects not only for cognitive function, but also for more serious brain disorders and diseases like dementia.
“Since bariatric surgery reversed this activity,” said Cercato, “we suspect the procedure may contribute to a reduced risk of Alzheimer's disease and other forms of dementia.”
It’s also likely that the results extend to weight-loss methods besides surgery: Losing weight the old-fashioned way, with diet and exercise, might have similar effects on brain function and Alzheimer’s risk.
If you are overweight or obese, talk with your doctor about which method of weight loss might be best for you. Whichever route you choose, all the research suggests that being a healthy weight is one of the most important things you can do for your long-term health.
The study is published in the Journal of Clinical Endocrinology & Metabolism.