Diet and Brain Health

Cognitive Function May Be Improved By Bariatric Surgery

For people with a Body Mass Index (BMI) of 35 or higher, bariatric surgery can be a life-saving procedure. According to the Mayo Clinic, the medical procedure, which involves making changes to your digestive system to help you lose weight, can reduce a person’s risk of weight-related health problems. These include heart disease, stroke, high blood pressure, high cholesterol, sleep apnea, type 2 diabetes, non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, and certain cancers, such as breast, prostate, and endometrial cancer.

Now a new study published in JAMA Network Open has found that bariatric surgery can affect brain structure and may improve cognitive function.

The Research

A team of researchers in the Netherlands analyzed data—including cognitive function—from 133 participants in a Bariatric Surgery Rijnstate and Radboudumc Neuroimaging and Cognition in Obesity study before (Roux-en-Y gastric bypass) bariatric surgery and at 6 months and 24 months post-surgery. The mean age was 47 and approximately 80% of the subjects were women. Only participants who completed measurements at all the following points in time were included:

• Neuropsychological tests: baseline, 6 months, 24 months

• MRI scans: baseline, 24 months

• Blood samples and anthropometric data: all time points

Primary outcomes included:

• Body weight


• Waist circumference

• Blood pressure

• Medication use

• Cognitive performance

• Brain volumes

• Cortical thickness

• Cerebral blood flow

• Spatial coefficient of variation

Secondary outcomes included:

• Cytokines

• Adipokines

• Depressive symptoms

• Physical activity

The Findings

First, the findings that were somewhat expected:

  1. At the 6-month and 24-month marks, BMI, mean body weight, waist circumference, blood pressure, and inflammatory markers were significantly lower.
  2. At the 24-month mark, medication use for comorbidities was substantially lower.
  3. For many participants, physical activity had increased.

As for cognitive function, the researchers found that, among the participants:

• 11% showed improvement in working memory.

• 24% showed improvement in verbal fluency.

• 31% demonstrated improvements in episodic memory.

• 40% were better able to shift their attention.

• 43% showed improvement in global cognition.

In addition, the temporal lobe—which is involved in processes such as memory, processing vision and sound, and recognizing language and objects—showed changes in function and structure for many participants. Even two years after bariatric surgery, for many of the study participants, the temporal cortex had higher cortical thickness.

Overall, cognitive improvement was sustained in approximately 40% of the participants at 24 months post-surgery. The researchers indicate that these results might be due to lower inflammation and adipokine secretion, remission of comorbidities, higher physical activity, and better mood.

Limitations to the Study

There were several limitations to the study, including:

• There was no control group to help the researchers conclude whether these outcomes were associated with prolonged obesity or aging.

• Less than 20% of the sample was male. Although the sex distribution of the study’s sample does represent the general bariatric surgery population, it’s important to note that brain atrophy is greater in women than in men.

• Cortical surface and curvature were not included. If these parameters had been included, they may have improved the researchers’ understanding of change in cortical volume and thickness.


Wendy Burt-Thomas writes about the brain, mental health and parenting.

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