Weight-loss surgery designed to combat over-eating and obesity can benefit the brain as well as the waistline, research suggests.
There is even some evidence that it may reduce the risk of Alzheimer’s disease, scientists believe.
Bariatric surgery is generally used as a last resort to help people who are dangerously overweight. It involves either reducing the size of the stomach or shortening the distance food travels through the digestive tract.
“We found some areas of their brains metabolised (processed to produce energy) sugars at a higher rate than normal weight women”
The procedures, available on the NHS, are known to be highly effective in cases of serious obesity. But they also appear to have a positive influence on brain activity, according to the new findings.
A study of the impact of bariatric surgery on 17 obese women found it produced distinct improvements in mental functions linked to planning, strategy and organisation.
Professor Cintia Cercato, from the University of Sao Paulo in Brazil, said: “When we studied obese women prior to bariatric surgery, we found some areas of their brains metabolised (processed to produce energy) sugars at a higher rate than normal weight women.
“In particular, obesity led to altered activity in a part of the brain linked to the development of Alzheimer’s disease – the posterior cingulate gyrus,” she said.
“Since bariatric surgery reversed this activity, we suspect the procedure may contribute to a reduced risk of Alzheimer’s disease and other forms of dementia,” she added.
It was already known that obese individuals are 35% more at risk of developing Alzheimer’s than people of normal weight.
The research focused on a procedure known as a Roux-en-Y gastric bypass (RYBG) which combines the two types of bariatric surgery.
Positron emission tomography (PET) brain scans and a range of neuropsychological tests were used to assess its effect over a period of six months.
Results from the obese women were compared with those from a “control” group of 16 lean women who did not undergo bariatric surgery.
The scans showed that the excessive brain activity seen in the obese women disappeared after the procedure. Six months post-surgery, brain metabolism levels were similar in both groups of women.
In addition, bariatric surgery seemed to improve the performance of the obese women in a test of “executive function”.
This is the brain’s ability to connect past experience and current action, and is involved in planning, organising and making strategic decisions.
Other tests measuring various aspects of memory and thinking ability showed no change after bariatric surgery.
The results appear in the Journal of Clinical Endocrinology & Metabolism, published by the Endocrine Society.
Professor Cercato said: “Our findings suggest the brain is another organ that benefits from weight loss induced by surgery.
“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.”