Want to stay sharp into old age? You might want to start hitting the gym.
New research suggests that a hidden trait in your body could hold the key to maintaining a younger brain — and the implications are huge.
“Better brain health, in turn, lowers the risk for future brain diseases, such as Alzheimer’s,” Dr. Cyrus Raji, a neuroimaging scientist and senior author of the study, said in a statement.
In the study, Raji and his colleagues evaluated 1,164 healthy adults averaging 55 years old using whole-body MRI scans.
These high-tech machines provide a detailed view of muscle, brain tissue and two types of fat: subcutaneous, which lies just under the skin, and visceral, the hidden kind that wraps around your organs deep in the abdomen.
The researchers then used AI to measure each person’s muscle and fat volume and estimate their “brain age” — how old the brain looks biologically based on its internal structure.
A brain that appears older than your actual age may be a sign of accelerated aging, while a younger-looking brain could signal a healthier mind.
This biomarker can help identify people at risk of cognitive decline years before symptoms appear, aiding early detection of diseases like Alzheimer’s and allowing for earlier intervention.
After running the algorithm, the team found that the balance between a person’s muscle and hidden belly fat had a major impact on brain age.
“While it is commonly known that chronological aging translates to loss of muscle mass and increased hidden belly fat, this work shows that these health measures relate to brain aging itself,” Raji said.
“The participants with more muscle tended to have younger-looking brains, while those with more hidden belly fat relative to their muscle had older-looking brains,” he explained. “The fat just under the skin wasn’t related to brain aging.”
In light of the findings, Raji suggested that building muscle and reducing visceral fat to improve this ratio is a realistic, actionable goal for anyone looking to support their brain health.
“This research has validated widely held hypotheses about the association between body composition biomarkers and brain health,” he said. “[It] provides a foundation for those biomarkers to be included in future trials of various metabolic interventions and treatments.”
That includes GLP-1s like Ozempic and Wegovy, which are used to treat conditions such as type 2 diabetes and obesity.
These blockbuster medications work by mimicking one or two hormones naturally produced by the body to regulate blood sugar, digestion and appetite. They slow the rate at which food leaves the stomach, helping people feel fuller for longer.
GLP-1s have surged in popularity in recent years, with nearly 12% of Americans having used them to slim down.
Over time, patients taking these drugs typically shed 15% to 25% of their body weight — but excess fat isn’t the only thing they’re losing.
Studies suggest that up to 40% of the weight loss from GLP-1s can come from lean mass, which includes muscles, bones and organs.
This loss could increase the risk of frailty and disrupt the muscle-to-visceral-fat ratio, potentially impacting brain age.
Raji suggested that the study’s findings could help guide the development of next-generation GLP-1s designed to target visceral fat more than subcutaneous fat while protecting muscle mass.
“Losing fat — especially visceral fat — while preserving muscle volume would have the best benefit on brain aging and brain health based on insights from our work,” he said.
“Thus, our study can inform future treatments by promoting research that quantifies MRI of body fat, muscle and brain age, which can help determine the optimal dosing regimens for GLP-1s to achieve the best outcomes in body and brain health.”
