This type of common middle-aged fat may predict Alzheimer’s

New research has established a link between a specific type of body fat and brain proteins that are the hallmark of Alzheimer’s disease.

The type of fat is especially common in middle-aged people — and can signal Alzheimer’s a full two decades sooner than symptoms of the memory disease.

In a study presented at the annual meeting of the Radiological Society of North America (RSNA), a team from the University of Washington School of Medicine linked visceral fat – which forms around vital organs such as the heart, liver and stomach – increasing the likelihood of developing dementia within two decades.

“This crucial result was discovered because we investigated the pathology of Alzheimer’s disease from middle age — in the 40s and 50s — when the disease’s pathology is in its earliest stages,” said lead study author Mahsa Dolatshahi, MD, MPH, postdoctoral research associate at Mallinckrodt. The Institute of Radiology (MIR) at Washington University School of Medicine in St. Louis, Mo.

“And possible modifications such as weight loss and reduction of visceral fat are more effective as a means of preventing or delaying the onset of the disease.”

One in 5 women and 1 in 10 men will develop Alzheimer’s in their lifetime.

Alzheimer’s is the most common form of dementia, characterized by a decline in memory, thinking and learning. Nearly 7 million Americans have been diagnosed with dementia, but researchers say millions more likely have symptoms of dementia but no official diagnosis.

Dolatshahi and his team focused their study on the link between Alzheimer’s and modifiable factors such as obesity and body fat distribution.

The study included 80 cognitively normal middle-aged subjects, meaning they had no current signs of dementia. Approximately 57.5% of these participants qualified as obese, and the average body mass index (BMI) of all participants was 32.31.

The CDC defines obesity as having a body mass index (BMI) of at least 30, and 20% of Americans meet this criteria.

Participants underwent brain positron emission tomography (PET), body MRI, metabolic assessment (glucose and insulin measurements) and a lipid (cholesterol) panel. MRI scans are used on the abdomen to measure the volume of subcutaneous fat, which is just under the skin, and visceral fat, which is deeper, less visible and surrounds the organs.

PET scans were used to measure traces associated with clumps of brain-clogging proteins called amyloid plaques, an indicative biomarker of Alzheimer’s.

The team found that higher levels of visceral fat were associated with increased amyloid, accounting for 77% of the effect of high BMI on amyloid accumulation.

“Our study showed that higher visceral fat was associated with higher PET levels of two characteristic pathological proteins of Alzheimer’s disease – amyloid and tau,” said Dolatshahi.

To our knowledge, our study is the only one to demonstrate these findings in middle age, where our participants are decades away from developing the earliest symptoms of dementia resulting from Alzheimer’s disease.

Dolatshahi and his team noted that lifestyle modifications that prevent or reduce the accumulation of visceral fat could theoretically help prevent or delay the development of Alzheimer’s disease.

Previous research found that visceral fat can lead to inflammation in the brain, one of the main mechanisms contributing to Alzheimer’s disease.

“A major implication of our work is that managing Alzheimer’s risk in obesity will need to include targeting the metabolic and lipid issues that often arise with higher body fat,” said senior study author Cyrus A. Raji, MD, Ph.D., associate professor of radiology at MIR.

Raji, Dolatshahi and their colleagues will also present a study showing the link between visceral fat, obesity and cerebral blood flow. In the latest study, the team found that those with high visceral fat showed lower blood flow to the brain.

“This work will have a significant impact on public health because nearly 3 out of 4 Americans are overweight or obese,” Raji said.

“Knowing that visceral obesity adversely affects the brain opens up the possibility that treatment with lifestyle modifications or appropriate weight loss medications could improve cerebral blood flow and potentially decrease the burden and risk of Alzheimer’s disease.”

Previous research has proven that refined carbohydrates and ultra-processed foods (UPF) are common culprits of belly fat and contributors to cognitive decline. Experts suggest that a Mediterranean diet is the best way to combat this fat and potentially prevent dementia. Additional measures to avoid the debilitating disease include regular exercise, abstinence from alcohol and quality sleep.