Weight loss: How bariatric surgery can also help improve cognition

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Researchers say bariatric surgery can provide numerous health benefits. shapecharge/Getty Images
  • Researchers are reporting that bariatric surgery provides physical health benefits as well as improved brain health and better cognition for many people.
  • They said the largest improvements in brain health were in episodic memory and attention.
  • Changes in overall health, including cognition function, remained two years after surgery.

Bariatric surgery is associated with health benefits other than weight loss, including improved cognition, overall health, blood vessel efficiency, and cortical thickness, according to a new study published in JAMA Network Open.


Researchers reported that the health benefits remained for some people as much as two years after the surgery.


The study included 133 participants, between the ages of 35 and 55, with a mean age of nearly 47. About 80% of the subjects were women.


Researchers used neuropsychological tests, MRI scans, and laboratory tests to assess cognition at baseline and again at 6 months and 24 months after surgery. The specific type of bariatric surgery used in the study was called Roux-en-Y gastric bypass.


The researchers collected data for weight loss via body weight, waist circumference, body mass index (BMI), blood pressure, and percentage of total body weight loss.


Results from the bariatric surgery and cognition study

At the end of the study, the researchers found that:


  • 11% participants showed improvement in working memory.
  • 31% participants demonstrated improvements in episodic memory.
  • 24% participants showed improvement in verbal fluency.
  • 40% participants were better able to shift their attention.
  • 43% showed improvement in global cognition.

Depressive symptoms also decreased after surgery.


The researchers also reported that neuroimaging of the temporal lobe showed changes in structure and function in many participants. Specifically, the temporal cortex had higher cortical thickness after surgery and remained so during the two-year follow-up. The temporal lobe is involved in processes such as memory, recognizing language and objects, and processing vision and sound.


Other findings from the study included:


  • Mean body weight, BMI, waist circumference, inflammatory markers, and blood pressure were significantly lower at 6-month and 24-month follow-ups.
  • Medication use for comorbidities was substantially lower at 24 months after surgery.
  • Physical activity increased in many participants.

“I found this quite interesting,” said Dr. Mir Ali, a bariatric surgeon and medical director of MemorialCare Surgical Weight Loss Center at Orange Coast Medical Center in California who was not involved in the study.


“We knew that obesity affected all the major organs in the body, but this study now shows that it also affects the brain. It is surprising because the brain does not have any fat cells,” Ali told Medical News Today.


The authors noted that losing weight frequently brings about a number of physical changes, including improvements in inflammatory biomarkers, co-morbidities, and depressive symptoms.


They also said that some obesity-accelerated brain aging might be improved or stabilized following bariatric surgery.


Limitations to the weight loss surgery study

The researchers reported several limitations to the study.


One was that the research did not include a control group, making it difficult to conclude whether the changes occurred because of prolonged obesity or aging.


Another limitation was that most participants were women. Because brain atrophy is more common in women, the results may not be translatable to the general population.


However, they also note that the gender distribution in their study is representative of the bariatric surgery population.


Understanding bariatric surgery

There are three main types of weight-loss surgery, according to the National Institute of Diabetes and Digestive and Kidney Diseases.


They include:


  • Gastric sleeve
  • Gastric bypass
  • Adjustable gastric band

“The gastric band was popular about 15 years ago. Now, the gastric sleeve is the most common,” Ali said. “The majority of people (about 80 percent) keep weight off after the surgery. The rest might slowly return to their previous eating habits and regain the weight. It is rare that someone would regain weight and return to their previous weight.”


“While the sleeve is the most common, gastric bypass has the highest long-term success rate,” he added. “Although not everyone who is overweight will have cognitive changes, those that do might see improvements in cognitive processes. Not everyone is going to see improved cognitive function because not everyone has decreased cognitive function that is caused by obesity.”


“However, when counseling people on weight loss and bariatric surgery, I would certainly go over the findings from this study,” Ali said. “I do think we need additional research to better understand these findings.”


Besides weight loss, these types of surgeries can help with related conditions, such as diabetes, high blood pressure, sleep apnea, and high cholesterol, according to the American Society for Metabolic and Bariatric Surgery.


These procedures modify the stomach and intestines, resulting in decreased food intake and increased feelings of fullness.