People with more muscle and less visceral fat tend to have brains that appear biologically younger, according to advanced MRI-AI analysis.
The results point toward lifestyle and therapeutic approaches that prioritize muscle preservation and targeted visceral fat reduction for better brain health.
Muscle–Fat Balance Linked to Younger Brain Age
Researchers report that people with more muscle and a lower ratio of visceral fat to muscle tend to show signs of a younger biological brain age. These findings come from a study that will be presented next week at the annual meeting of the Radiological Society of North America (RSNA). Visceral fat refers to the fat stored deep in the abdomen around important internal organs.
“Healthier bodies with more muscle mass and less hidden belly fat are more likely to have healthier, youthful brains,” said senior study author Cyrus Raji, M.D., Ph.D., associate professor of radiology and neurology in the Department of Radiology at Mallinckrodt Institute of Radiology at Washington University School of Medicine in St. Louis, Missouri. “Better brain health, in turn, lowers the risk for future brain diseases, such as Alzheimer’s.”
How Body Composition Reflects Brain Health
Brain age is an estimated biological age of the brain based on a structural MRI scan. Muscle mass measured through body MRI can serve as an indicator for interventions aimed at reducing frailty and supporting brain health, while brain age calculated from structural images may help identify Alzheimer’s disease risk factors, including muscle loss.
“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,” Dr. Raji said. “It shows muscle and fat mass quantified in the body are key reflectors of brain health, as tracked with brain aging.”
MRI + AI Reveal Muscle, Fat, and Brain Aging Patterns
In the ongoing research, whole-body MRI scans were performed on 1,164 healthy adults (52% women) across four locations. The average chronological age of the group was 55.17 years. The team used MRI with T1-weighted sequences, which highlight fat as bright and fluid as dark, allowing clear visualization of muscle, fat, and brain tissue. An artificial intelligence (AI) tool then measured total normalized muscle volume, visceral fat (hidden belly fat), subcutaneous fat (fat under the skin) and brain age.
The analysis showed that individuals with a higher visceral fat to muscle ratio tended to have an older brain age, while subcutaneous fat did not meaningfully relate to brain age.
“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,” Dr. Raji said. “The fat just under the skin wasn’t related to brain aging. In short, more muscle and a lower visceral fat to muscle ratio were linked to a younger brain.”
Actionable Steps: Build Muscle, Reduce Visceral Fat
Building muscle and reducing visceral fat are actionable goals, he added. Whole-body MRI and AI brain-age estimates provide objective endpoints to design and monitor interventions, including programs or therapies under study that lower visceral fat while preserving muscle.
Dr. Raji noted that this work demonstrates how body and brain health are closely linked.
“This research has validated widely held hypotheses about the association between body composition biomarkers and brain health and provides a foundation for those biomarkers to be included in future trials of various metabolic interventions and treatments,” he said.
GLP-1 Drugs, Muscle Loss, and Future Therapies
While widely prescribed glucagon-like peptide-1 (GLP-1) weight loss drugs, such as Ozempic, are powerful at inducing fat loss, they may also be related to a higher burden of muscle loss. According to Dr. Raji, the findings of this study could inform the design of future therapeutics, such as GLP-1 medications that target visceral fat more than subcutaneous fat and minimize muscle loss.
Toward Smarter Fat-Loss Treatments for Brain Health
“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.”
Meeting: 111th Scientific Assembly and Annual Meeting of the Radiological Society of North America (RSNA)
Co-authors are Somayeh Meysami, M.D., Soojin Lee, Ph.D., Saurabh Garg, M.Sc., Nasrin Akbari, M.Sc., Rodrigo Solis Pompa M.D., M.H.Sc., Ahmed Gouda, M.Sc., Thanh Duc Nguyen, Ph.D., Saqib Abdullah Basar, M.B.B.S., M.P.H., Yosef G. Chodakiewitz, M.D., David A. Merrill, M.D., Ph.D., Alex Exuzides, Ph.D., M.D., Amar P. Patel, M.D., Daniel J. Durand, M.D., M.B.A., and Sam Hashemi, M.Sc.
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