Visceral fat refers to fat stored deep in the abdomen, around vital internal organs. Scientists have discovered that people with more muscle and a lower ratio of visceral fat to muscle tend to have younger, healthier brains. The related research will be presented at the Radiological Society of North America (RSNA) annual meeting soon.
Brain age generally refers to the biological age estimated based on brain structure as shown in MRI scans. Body MRI can track muscle mass, which is one indicator of overall health. Brain age estimated from structural scans helps reveal risk factors for Alzheimer's disease, such as muscle loss.
Cyrus Raji, an associate professor at Washington University in St. Louis who conducted the study, said that people with more muscle mass and less abdominal fat are more likely to have healthy, youthful brains. Higher levels of brain health reduce the risk of developing brain diseases such as Alzheimer's.
“As the body ages, muscle mass decreases and visceral fat increases, and our research shows that muscle and fat mass are key indicators of brain health and are closely related to brain aging,” Raji said.
This study used whole-body MRI to assess 1,164 healthy adults (52% of whom were women) at four study sites. The participants' mean age was 55.17 years. The research team used artificial intelligence (AI) algorithms to measure muscle volume, visceral fat, subcutaneous fat, and brain age.
The results showed that participants with more muscle mass tended to have younger brains, while those with more visceral fat had older brains, and subcutaneous fat was not associated with brain aging. "In short, more muscle and a lower ratio of visceral fat to muscle mass are associated with a younger brain," Raji said.
Raji explained that focusing on building muscle and reducing visceral fat is actionable. Whole-body MRI and AI-based brain age estimation provide clear benchmarks for those who want to maintain or increase muscle mass while reducing visceral fat. Furthermore, the findings highlight the close link between physical and brain health.
Raji said the study validates the hypothesis about the link between body composition biomarkers and brain health and lays the foundation for incorporating these biomarkers into future trials of metabolic interventions and treatments.
Commonly used glucagon-like peptide-1 (GLP-1) weight-loss drugs, such as smegglutide, can effectively reduce body fat, but can also lead to muscle loss. Raji stated that the research results will help determine the optimal dosage regimen for GLP-1 and guide the development of next-generation therapies aimed at reducing visceral fat rather than subcutaneous fat and maintaining muscle mass.
“According to our research, losing fat, especially visceral fat, while maintaining muscle mass is extremely beneficial for maintaining brain health,” Raji said.
