Dec. 3, 2024 – Having belly fat during your 40s and 50s may be a sign that the brain is already becoming sick and shrinking, increasing the risk of Alzheimer’s disease later in life.
Researchers were able to directly link a type of abdominal fat called visceral fat to brain changes that are often seen in people with dementia, including Alzheimer’s disease. Visceral fat is a type of fat that builds up between and around your organs and can reduce blood flow to the brain.
The findings are being presented at this week’s Radiological Society of North America conference in Chicago. They are important because they point to the significance of weight management early in life for preventing the devastating disease.
The study was small and included 80 people, all in middle age and with no cognitive problems. The average age was 49, and a little over half of the participants met the criteria for obesity. The researchers used imaging to evaluate the types of fat around the people’s abdomens, livers, and thighs and to look for signs of brain changes known to impact Alzheimer’s risk, including evidence of amyloid plaques and tau tangles.
“To our knowledge, our study is the only one to demonstrate these findings at midlife where our participants are decades out from developing the earliest symptoms of the dementia that results from Alzheimer's disease,” said Mahsa Dolatshahi, MD, MPH, a postdoctoral research associate at the Mallinckrodt Institute of Radiology (MIR) at Washington University School of Medicine in St. Louis, MO, in a news release.
The researchers also found that people with a condition that can lead to diabetes called high insulin resistance are at increased risk of having amyloid brain plaques in middle age. Low levels of HDL cholesterol were also linked with amyloid plaques.
"A key implication of our work is that managing Alzheimer's risk in obesity will need to involve targeting the related metabolic and lipid issues that often arise with higher body fat," said senior study author Cyrus A. Raji, MD, PhD, associate professor of radiology at MIR.
The findings build upon a similar study that was presented by the same research team at last year’s RSNA conference, which linked belly fat in midlife to memory loss up to 15 years later.
Nearly 7 million people in the U.S. have Alzheimer’s dementia, most of whom are 75 or older. The earliest symptoms of dementia include losing interest or enthusiasm for things, depression, and difficulty remembering recent conversations, names, or events. Later symptoms include confusion, communication problems, and behavioral changes. People with advanced disease have difficulty walking, speaking, and swallowing.
