by Dr. Meenakshy Varier on  August 6, 2020 at 12:58 PM Health Watch
Highlights:
  • Neuroimaging scans show a decreased blood flow in all regions of the brain across categories of overweight, obesity, and morbid obesity.
  • Obesity-related brain changes affect similar regions of the brain that are vulnerable to cognitive disorders like Alzheimer’s disease, like the hippocampus
  • Obesity should be targeted for interventions designed to improve brain function, prevent Alzheimer disease, and optimize cognition in younger populations

An increase in body weight is linked to a decrease in brain activity and blood flow. A decrease in blood flow in the brain is a major risk factor for developing many psychiatric and cognitive conditions like Alzheimer's disease.

Alzheimer's disease (AD) is the most common cause of dementia, and lifestyle factors like midlife-obesity, are increasingly recognized as risk modifiers for AD. Modifying lifestyle factors are important as currently there is a lack of effective treatments for AD.
Alzheimer’s Disease Risk Increases With Body Weight

Previous studies have shown that overweight and obesity-related brain changes occur in the same brain region, targeted by AD pathology, such as the hippocampus. Obesity is a systemic pro-inflammatory state that causes hypoperfusion by promoting hypertrophic inward remodeling of the cerebral vasculature.


The findings of one of the largest studies that link obesity to brain dysfunction, state that low cerebral flow that can be assessed by neuroimaging scans, is a major predictor that a person will develop Alzheimer's disease. It is also associated with depression, ADHD, bipolar disorder, schizophrenia, traumatic brain injury, addiction, suicide, and other conditions.

Functional neuroimaging is one of the major resources in identifying potential risk factors for dementia and age-related changes in the brain. Regional cerebral blood flow is used to track obesity-related brain abnormalities.

Scientists analyzed over 35,000 functional neuroimaging scans using single-photon emission computerized tomography (SPECT) from more than 17,000 individuals to measure blood flow and brain activity. The findings of the new brain imaging study are published in the Journal of Alzheimer's Disease.

Currently, 72% of Americans are overweight, and around 42% are obese.

"This study shows that being overweight or obese seriously impacts brain activity and increases the risk for Alzheimer's disease as well as many other psychiatric and cognitive conditions," explained Daniel G. Amen, MD, the study's lead author and founder of Amen Clinics, one of the leading brain-centered mental health clinics in the United States.

Neuroimaging of baseline scans or while in resting state, as well as concentration scans, while performing a concentration task, has revealed striking patterns of progressively reduced blood flow in all regions of the brain across categories of underweight, normal weight, overweight, obesity, and morbid obesity.

In particular, brain areas vulnerable to Alzheimer's disease, the temporal and parietal lobes, hippocampus, posterior cingulate gyrus, and precuneus, were found to have reduced blood flow along the spectrum of weight classification from normal weight to overweight, obese, and morbidly obese.

George Perry, PhD, Editor-in-Chief of the Journal of Alzheimer's Disease and Semmes Foundation Distinguished University Chair in Neurobiology at The University of Texas at San Antonio, stated, "Acceptance that Alzheimer's disease is a lifestyle disease, little different from other age-related diseases, that is the sum of a lifetime is the most important breakthrough of the decade. Dr. Amen and collaborators provide compelling evidence that obesity alters blood supply to the brain to shrink the brain and promote Alzheimer's disease. This is a major advance because it directly demonstrates how the brain responds to our body."

There is an imminent need to address obesity to improve brain function. It could be in the form of initiatives to prevent Alzheimer's disease or attempts to optimize cognition in younger populations. This is important in improving outcomes across all age groups.

Dr. Amen added, "One of the most important lessons we have learned through 30 years of performing functional brain imaging studies is that brains can be improved when you put them in a healing environment by adopting brain-healthy habits, such as a healthy calorie-smart diet and regular exercise."

Source: Medindia

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