A groundbreaking study published in the Journal of the American Geriatrics Society has unveiled a perplexing connection between increasing fat deposits in muscle tissue and heightened cognitive decline risk. Over a span of five years, researchers observed that elevated levels of fat in thigh muscles were associated with accelerated and more significant cognitive decline in older individuals, irrespective of factors such as overall weight, other body fat deposits, muscle strength or mass, and traditional dementia risk factors.
Dr. Caterina Rosano, a professor of epidemiology at the University of Pittsburgh’s School of Public Health and corresponding study
author, highlighted the unique role of muscle adiposity in cognitive decline, distinct from other fat types or muscle characteristics. Dr. Rosano expressed the need to understand the communication between muscle fat and the brain, along with investigating whether reducing muscle adiposity could potentially lower the risk of dementia.
The location of muscle fat storage holds significance in this context. The study involved 1,634 adults aged 69 to 79 years, with muscle fat measured using CT scans at the beginning and end of a six-year period. Cognitive function assessments were conducted at multiple intervals throughout the study duration. Dr. Rosano emphasized that while fat is generally detrimental to the brain due to the release of inflammatory factors, muscle, as an endocrine organ, produces substances beneficial for brain health. This insight formed the basis for exploring the impact of muscle adiposity on the brain.
“It’s something that hides in the body,” Dr. Rosano commented, emphasizing the hidden nature of fat. Kelsey Costa, a registered dietitian nutritionist and health research consultant, highlighted the significance of intramuscular fat as a predictor of muscle and mobility function, metabolic health, and various conditions like diabetes, stroke, and cardiovascular disease. Costa noted that the study’s findings indicate that intramuscular fat is also a significant risk factor for cognitive decline.
The study’s results were consistent among both Black and white men and women. Researchers are now exploring whether fat stored in muscles in other parts of the body may also contribute to cognitive risks. While dieting may not directly reduce muscle adiposity, Dr. Rosano underlined the importance of addressing other risk factors for dementia, such as smoking, excess weight, high blood pressure, and diabetes, especially for individuals with fat in their muscles.
Costa emphasized the importance of maintaining a healthy weight, controlling fat accumulation, and adopting dietary interventions and increased physical activity to maintain optimal intramuscular fat levels. Future research conducted by University of Pittsburgh scientists aims to investigate pharmacological interventions, potentially involving the muscle protein myostatin, to reduce muscle adiposity.
“To prevent or slow cognitive decline, medical professionals should emphasize healthy lifestyle behaviors with a focus on weight management, nutrient-dense eating patterns, and muscle strength/mass maintenance,” Costa advised. “To maintain muscle health, individuals must consume adequate dietary protein and engage in physical activity, including progressive resistance training.”