Protect Your Brain From Dementia by Keeping a Healthy Weight

Dorian Martin Health Guide
  • Are you overweight or obese? If so, you have a significantly higher risk of developing dementia.


    Researchers have learned that people who are obese have a 64-percent higher risk of developing dementia than a person who is a normal weight. In comparison, people whose weight is classified as obese have a 26-percent higher risk of developing this brain condition than their leaner family members and friends.
    Does that extra weight really make a difference? A new study out of Brazil suggests that it does. This study involved 17 severely obese women who had an average body mass index of 50.1 (which is considered super obese) and 16 women who were at a normal weight. None of the participants had diabetes or a family history of dementia.

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    The researchers looked at brain function before and after weight-loss surgery. The study participants also took an IQ test as well as six other assessments to determine their memory and executive function at the start of the study. Researchers took blood samples and asked the participants to undergo positron emission tomography (PET) scans to measure their brain’s blood flow, oxygen use and sugar metabolism. This nuclear medicine imaging allows the researchers to see firsthand how well the brain is functioning.


    The 17 participants then underwent gastric bypass surgery. This operation decreased the stomach to the size of an egg and diverted food past much of the small intestine.  This procedure reduces the calories that the study participants’ bodies are able to absorb. Half a year after the surgery, the participants’ body mass index was measured and found to be an average of 37.2, which is considered severely obese.


    The researchers then reassessed these 17 participants to see if the surgery made any difference for their brain.  Their analysis found that the obese participants had higher brain metabolism levels prior to the surgery than the 16 leaner participants. Additionally, the PET scans showed that the obese women’s brains seemed to work harder than the brains of the 16 leaner participants. This additional activity showed up primarily in the right hemisphere, which often becomes more active as a way to compensate for cognitive decline.  


    After the surgery and the resultant weight loss, the participants had lower brain metabolism levels; furthermore, differences in the PET scans that were notable between the two groups of participants prior to surgery were no longer apparent. The 17 participants also had higher scores on assessments of executive function, which involves planning and organization.


    The weight loss caused by the surgery also caused the 17 women to be more sensitive to insulin and to have lower blood levels of proteins that are associated with inflammation. The participants’ levels of the anti-inflammatory hormone GLP-1, which may reduce beta-amyloid plaques that are seen in Alzheimer’s disease, also increased following the surgery.


    This study provides additional impetus to remain a healthy weight throughout one’s life (and to lose weight if you’ve packed on extra pounds). Carrying additional weight also increases the risk of developing cardiovascular disease and diabetes, which are both risk factors for developing dementia. So as we get into the cooler months, make yourself a promise to get outdoors and exercise. Embrace a healthy diet that includes lots of produce and whole grains, as well as lean protein. Also, you probably will need to lower your calorie consumption as you age since your body becomes less efficient in burning calories.


  • Primary Sources for This Sharepost:

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    Kaplan, K. (2014). Lower weight, get smarter? Well, maybe. Houston Chronicle.


    Margues, E.L., et al. (2014). Changes in neuropsychological tests and brain metabolism after bariatric surgery. The Journal of Clinical Endocrinology & Metabolism.
    RadiologyInfo.org. (2013). Positron emission tomography.


    Sifferlin, A. (2014). This is what weight loss does to your brain. Time.com.

Published On: August 31, 2014