Hidden Belly Fat in Midlife Linked to Alzheimer’s Disease

Middle-aged adults who have visceral fat surrounding their internal organs in their belly may be at higher risk of developing Alzheimer’s disease.

Having such fat deposits could trigger changes in the brain related to Alzheimer’s up to 15 years before symptoms of the neurological disease appear — and as early as age 50 — according to research presented at the annual meeting of the Radiological Society of North America.

The findings have not yet been published in a peer-reviewed journal.

Details from the belly fat study

In their study, researchers sought to identify associations between amyloid and tau proteins — known to interfere with cellular communication in the brain — with high body mass index (BMI) scores, obesity, insulin resistance, and fatty abdominal tissue in middle-aged individuals who had no signs of cognitive issues.

Researchers led by Dr. Mahsa Dolatshahi, a post-doctoral research fellow with Mallinckrodt Institute of Radiology (MIR) at Washington University School of Medicine in St. Louis, previously reportedTrusted Source that higher visceral to subcutaneous fat ratio in the belly was associated with higher presence of amyloids in the precuneus cortex, the brain region known to be affected early by amyloid pathology in Alzheimer’s disease.

Higher levels of visceral fat also were associated with increased inflammation in the brain, those researchers reported.

In the new study, the relationship between belly fat and Alzheimer’s was found to be stronger in men than among women.

“Even though there have been other studies linking BMI with brain atrophy or even a higher dementia risk, no prior study has linked a specific type of fat to the actual Alzheimer’s disease protein in cognitively normal people,” said Dolatshahi in a press statement. “Similar studies have not investigated the differential role of visceral and subcutaneous fat, especially in terms of Alzheimer’s amyloid pathology, as early as midlife.”

“Since we know visceral fat is already linked to so many bad health outcomes, including heart health, it makes sense that it’s also linked to poorer brain health, but it’s important that we do the studies like these to define that link with evidence,” Dr. Mary Ellen Koran, an assistant professor of radiology and radiological sciences at Vanderbilt University Medical Center & School of Medicine in Tennessee, told Medical News Today.

How visceral fat can cause inflammation

Dolatshahi said that inflammatory secretions of visceral fat “may lead to inflammationTrusted Source in the brain, one of the main mechanisms contributing to Alzheimer’s disease.”

“We don’t know whether this is a cause or effect—perhaps an unhealthy lifestyle is linked to more visceral fat but is also linked to worse brain health,” said Koran, whose expertise includes identifying Alzheimer’s disease through radiology. “This warrants more research in this direction before we can move this clinically.”

For example, she said, “I don’t think we know what a ‘normal’ amount of visceral fat, is and that’s something that needs to be explored.”

How this research could help in Alzheimer’s diagnosis

Researchers said the findings could point the way to earlier detection of Alzheimer’s disease among an at-risk population.

“By moving beyond body mass index (BMI) in better characterizing the anatomical distribution of body fat on MRI, we now have a uniquely better understanding of why this factor may increase risk for Alzheimer’s disease,” said Dr. Cyrus Raji, a senior study author and an associate professor of radiology and neurology and director of neuromagnetic resonance imaging at MIR.

Koran said the problem with using BMI to assess health risks is that it doesn’t account for individuals with high amounts of muscle mass. Likewise, using waist circumference as a yardstick doesn’t distinguish between visceral and subcutaneous fat.

“We know that visceral fat is linked to lots of poor health outcomes, so perhaps we need other ways to evaluate visceral fat, and imaging lends itself well to seeing what’s going on inside the body non-invasively,” she said. “Perhaps we will be able to quantify this with a low-cost, non-radiation modality like ultrasound in the future.”

Why it’s important to reduce belly fat

Reducing belly fat might reduce Alzheimer’s risk, the study suggests.

“One strategy that has been proven effective in reducing belly fat is engaging in regular aerobic exercise,” such as running, swimming, cycling, and dancing, all of which get your heart rate up and increase oxygen flow throughout the body, said Taylor Wilson, a nutrition and exercise expert and founder of Active Recovery Companions.

“When you engage in aerobic exercise, your body burns calories, including those stored in the belly area,” he told Medical News Today. “Over time, this calorie burn can lead to overall weight loss and a reduction in belly fat. Additionally, aerobic exercise has been shown to have a more significant impact on belly fat reduction compared to resistance training alone.”

“We know we can target fat with healthy diets and exercise,” Koran added, “but now there are also effective drugs coming to market, like Ozempic. But we’d still have to study the long-term effects of these drugs on visceral fat and on brain health.”

Ozempic and other similar medications have been approvedTrusted Source by the Food and Drug Administration for type 2 diabetes but most haven’t yet been given the OK to officially be used for weight loss. Some of those drugs are now being prescribed off-label by some doctors for weight loss.

So far, Wegovy is the only one of these medications to be approved for weight loss.

Source : Medical News Today