How is Muscle Fat Linked to Cognitive Decline?

According to recent research, there is a growing consensus among experts that the presence of muscle fat in the thighs of older adults could be an indicator of an increased risk of cognitive decline. This finding has shed light on the potential link between body fat distribution and its impact on brain health. It is believed that the fat stored in various areas of the body, including the thighs, can lead to inflammatory conditions that affect the brain. Chronic inflammation has also been associated with a range of cognitive impairments, including memory loss, decreased attention span, and overall decline in cognitive function. Read on to find out how muscle fat is linked to cognitive decline.

A study recently published in the Journal of the American Geriatrics Society in June 2023 has revealed that individuals who experience an increase in muscle fat over time may face a higher risk of cognitive decline. This finding is particularly relevant for older adults.⁽¹⁾

This new research has indicated that a rise in fat levels, specifically within the thigh muscles over a five-year period, is associated with accelerated and more substantial cognitive decline among both men and women in the elderly population. Remarkably, this relationship between muscle adiposity (muscle fat) and cognitive decline remained significant even after accounting for factors such as overall body weight, other fat deposits in the body, muscle strength or mass, and traditional risk factors for dementia.⁽²⁾

According to Dr. Caterina Rosano, one of the study authors and a professor of epidemiology at the University of Pittsburgh’s School of Public Health, the uniqueness of muscle adiposity in its impact on cognitive decline. Research has now shown that this particular type of fat appears to play a distinct role in the cognitive aging process as compared to other types of fat or muscle characteristics.⁽³⁾

The research team further acknowledged the need for more investigation to comprehend the mechanisms by which muscle fat and the brain interact and communicate. They aim to explore whether reducing muscle adiposity could potentially mitigate the risk of dementia.

In the study conducted by Dr. Caterina Rosano and her colleagues, the team made use of CT scans to measure muscle fat in a group of 1,634 adults aged between 69 and 79 years at the beginning and end of a five-year period. Cognitive function assessments were conducted at multiple time points during the study, specifically at years 1, 3, 5, 8, and 10.⁽⁴⁾

This muscle fat is typically known to have adverse effects on the brain since it releases inflammatory substances into the bloodstream. Conversely, muscle, being an endocrine organ, produces factors that are beneficial for brain health. This understanding formed the basis for looking at the potential impact of muscle adiposity on the brain.⁽⁵⁾

It is important to know that fat is more complex than it appears, as it can be concealed within the body. Intramuscular fat has already been identified as a predictor of muscle and mobility function, as well as metabolic health. Health conditions like diabetes, stroke, and cardiovascular disease have already been linked to intramuscular fat. This is why the study’s results indicated that intramuscular fat should also be considered an important risk factor for cognitive decline.

Other experts have also lent their support to the findings of the study since the outcomes suggest intramuscular fat’s significance in cognitive decline is similar for both Black and white men and women.⁽⁶⁾

This research underscored the potential negative effects of intramuscular fat on cognitive function and also emphasized the need for further research in this area. It is now believed that understanding the role of muscle adiposity and its impact on brain health can potentially contribute to the development of preventive strategies and interventions to reduce the risk of cognitive decline in older adults.

The decision of the research team to focus on studying fat in the thighs was based on the fact that this region of the body contains substantial muscle mass, making it easier to detect fat deposits using CT scans. However, ongoing research is now also investigating whether fat stored in muscles in other parts of the body could also contribute to increased cognitive risks.

While the exact reason for the presence of fat in muscles is not yet fully understood, its measurement can provide valuable insights. Having fat in the muscles serves as a warning sign, indicating the need for individuals to exercise extra caution regarding other risk factors associated with dementia.^{(7, 8, 9)}

These additional risk factors may include smoking, excessive weight or obesity, high blood pressure, and diabetes. It is important for individuals with muscle fat to be particularly careful about managing these factors to mitigate the potential cognitive risks they may pose.^{(10, 11)}

By identifying and addressing these risk factors, individuals can take proactive steps to reduce their likelihood of cognitive decline and enhance their overall brain health. However, further research is still necessary to fully comprehend the mechanisms underlying the relationship between muscle fat and cognitive function.

While dieting may not directly target the reduction of muscle adiposity, it is important to recognize that muscle fat is not the sole factor impacting brain health. There are other aspects as well that can have negative effects on the brain as well.

It is important to know that intramuscular fat accumulation tends to increase with age and obesity, making it crucial to maintain a healthy weight and control excess fat buildup. This highlights the significance of adopting strategies to keep intramuscular fat levels within an optimal range.

To achieve this, several approaches can be employed. First, making dietary changes can be beneficial. A well-balanced diet that includes a variety of nutrient-rich foods such as fruits, vegetables, whole grains, lean proteins, and healthy fats can help support overall health and weight management. It is important to focus on portion control, limit processed and high-sugar foods, and prioritize nutrient-dense choices.⁽¹²⁾

In addition to dietary modifications, incorporating strength training exercises into one’s fitness routine can be advantageous. Strength training helps build and maintain muscle mass, which can aid in reducing intramuscular fat levels. This can involve exercises that target major muscle groups, such as weightlifting, resistance band workouts, or bodyweight exercises.⁽¹³⁾

Engaging in regular aerobic exercise is also beneficial. Activities like walking, jogging, cycling, swimming, or dancing can help burn calories, improve cardiovascular health, and contribute to overall weight management.⁽¹⁴⁾

Furthermore, ensuring adequate sleep is crucial for maintaining optimal brain health and managing weight. Poor sleep habits have been linked to weight gain and metabolic disturbances, which can influence muscle adiposity. Establishing a consistent sleep schedule and creating a conducive sleep environment can support quality sleep.⁽¹⁵⁾

It is important to note that these strategies should be implemented as part of a holistic approach to overall health and well-being. Consulting with healthcare professionals, such as registered dietitians, personal trainers, or physicians, can provide personalized guidance and recommendations based on individual circumstances and goals.

Many researchers are exploring potential pharmacological interventions to address muscle adiposity. There are studies going on to investigate various substances, including the natural muscle protein myostatin, as potential targets for reducing muscle fat. It is important for researchers to actively pursue interventions aimed at reducing intramuscular fat levels. By doing so, researchers can determine if such interventions have the potential to mitigate the risk of cognitive decline in aging populations.

The implementation of lifestyle modifications such as dietary changes, exercise, and improved sleep, represents a comprehensive approach to address the risk factors associated with cognitive decline. By pursuing these multifaceted strategies, researchers and healthcare professionals aim to enhance our understanding of the complex relationship between muscle fat and brain health, ultimately offering potential avenues for preventive and therapeutic interventions in the future.

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