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  • Researchers at the Radiological Society of North America have linked a specific type of body fat to the development of Alzheimer’s Disease.
  • Obesity is already a risk factor for the development of Alzheimer’s, but this is the first time research has linked that risk with a specific type of fat.
  • The research opens up new avenues for prevention by focusing treatment on fat loss.

Belly fat in middle age is a predictor of Alzheimer’s Disease, according to new research presented by the Radiological Society of North America.

Researchers looked at visceral fat, a specific type of fat that makes up only a small portion of an individual’s body mass, but is critically located in the abdominal cavity, in close proximity to many vital organs. Visceral fat is sometimes called hidden fat because it is not visible from the outside.

In a new study presented at the RSNA Annual Meeting, visceral fat was associated with changes in the brain that are an early signal of the development of Alzheimer’s Disease.

Dr. Heather M. Snyder, PhD, the Alzheimer’s Association’s Vice President of Medical and Scientific relations, told Healthline that the study, although small, was important.

“We know there are associations seen in past large studies that connect things like body mass index and obesity with later life risk of memory changes and possibly dementia. This new work seeks to understand the associations of things like obesity and BMI to the brain’s structure — and maybe overall health — as it relates to Alzheimer’s,” she said. Snyder was not involved with the study.

To conduct the study, researchers analyzed data from 54 participants ranging in age from 40-60 years old. All of the participants were cognitively healthy, but clinically obese, with an average BMI of 32. Using MRI scans the team was able to take images of the abdominal cavity and measure the amount of both visceral fat and subcutaneous fat (the more common type of fat found underneath the skin).

The team also took MRI brain scans to observe any potential associations between brain volume and visceral fat. Of particular interest is the thickness of the cortex, which controls important functions like language, reasoning, and memory.

Alzheimer’s Disease is known to destroy neurons and their connections in the cortex, resulting in loss of volume or “shrinking” as it progresses.

The researchers also used a battery of other relevant tests that could indicate brain changes or biomarkers for inflammation and Alzheimer’s development, including glucose tolerance tests (insulin resistance), and PET scans focusing on amyloid plaques and tau tangles — the “plaques and tangles” that are a hallmark of Alzheimer’s.

Participants with a higher ratio of visceral fat to subcutaneous fat had higher levels of tau and amyloid proteins in their brains identified through the PET scans. A higher ratio of visceral fat was also associated with more inflammation, another risk factor for Alzheimer’s.

“Even though there have been other studies linking body mass index (BMI) with brain atrophy or even a higher dementia risk, no prior study has linked a specific type of fat to the actual abnormal Alzheimer disease protein in cognitively normal persons up to 25 years before they would show the earliest symptoms of Alzheimer disease,” Dr. Cyrus A. Raji, MD, PhD, an Associate Professor of Radiology and Neurology and Director of Neuromagnetic Resonance Imaging at the Washington University School of Medicine, told Healthline.

And this is good news. Not only does the study help shed more light on one of the biological pathways that can lead to Alzheimer’s but also promotes the important message that some of these risk factors can be identified and modified early on.

“We are excited to see these initial findings and look forward to more work and collaborations in this area, with a focus on brain health. The picture on the relationships between body components and brain health is evolving, and we are excited to study the potential mechanisms linking these entities,” said Raji.

Lifestyle changes that include eating healthy and increasing exercise can help improve the amount of visceral fat on your body, even if it’s not visible to the naked eye. Even if you’re not losing weight, aerobic exercise is still good habit for overall health. Be careful though, not all exercise is equal; doing sit ups, for example, might help tighten up your abs, but it isn’t going to have a big effect on abdominal fat.

The Alzheimer’s Association encourages individuals to try a variety of activities to help keep their brain’s sharp, including:

  • Exercise
  • Reading
  • Eating healthy
  • Stopping smoking

You can find out more from their guide, “10 Ways to Love Your Brain.”

“This is such an exciting time in research, and studies like this will help us better understand these risk-related links,” said Snyder.

Visceral fat, which is found around in the organs in the abdominal cavity, is linked to other markers that indicate the development of Alzheimer’s Disease.

Researchers used brain and body imaging (MRI and PET scans), as well as additional testing to demonstrate the association.

The research encourages individuals to make healthy lifestyle changes, particularly in regard to their weight, earlier in life to help prevent Alzheimer’s.