Image by Mohamed Hassan on Pixabay

“Dr. Amen and collaborators provide compelling evidence that obesity alters blood supply to the brain to shrink the brain and promote Alzheimer’s disease.”

COSTA MESA, Calif. – Health experts say around half of American adults are overweight or obese. While excessive body weight is linked to a number of serious health conditions, including diabetes and heart disease, a new study reveals it can also reduce blood flow to the brain. Researchers warn this can put overweight individuals at great risk for Alzheimer’s disease.

The study examines brain blood flow in 17,721 adults between 18 and 94. To do this, researchers use a brain imaging technique known as single photon emission computed tomography (SPECT).

SPECT’s results showing the decrease in blood flow based on body mass. (Credit: Amen Clinics)

SPECT is a technique in which doctors inject a radioactive tracer into a patient’s blood and then use a special camera to look at the flow of blood. Participants were then split into five categories: underweight, normal weight, overweight, obese, and morbidly obese — to examine blood flow in each of their brains. The brain scan data reveals lower blood flow across virtually all brain regions as body weight increases.

These findings have important implications for learning and memory disorders, such as Alzheimer’s disease. Low brain blood flow is a strong predictor of future Alzheimer’s cases. The study also finds particularly strong links between body weight and blood flow in several brain regions known to be affected by Alzheimer’s disease. These areas includes the temporal and parietal lobes, hippocampus, posterior cingulate gyrus, and precuneus.

A healthy body’s impact on the brain

“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,” says lead author Dr. George Amen in a media release.

“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,” adds George Perry, editor-in-chief of the Journal of Alzheimer’s Disease.

The Centers for Disease Control and Prevention says Alzheimer’s is the most common form of dementia. Symptoms typically appear after age 60 and the risks increase as you get older. The CDC adds nearly 43 percent of Americans adults over 60 are obese.

The study is published in the Journal of Alzheimer’s Disease.

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