Hidden fat in muscles linked to higher heart attack risk
New research published in the "European Heart Journal" indicates that individuals with higher levels of hidden fat in their muscles are more likely to be hospitalised or die due to heart attacks and heart failure. Researchers assert that body mass index (BMI) is not a significant factor.
The latest research, published in the European Heart Journal, suggests that intramuscular fat can significantly increase the risk of heart disease, irrespective of body mass index (BMI). The research team, led by Prof. Viviana Taqueti of Brigham and Women's Hospital and Harvard Medical School, conducted studies that provided new insights into the impact of intramuscular fat on heart health.
Intramuscular fat and heart health
Intramuscular fat is primarily known in gastronomy — the renowned Japanese Wagyu beef owes its prized "marbling" to it. Farmers achieve this by providing cows with a stress-free life, comfortable living conditions, abundant food, minimal exertion, and even relaxing massages. Unfortunately, in humans, intramuscular fat can lead to serious health issues.
The study revealed that individuals with higher levels of muscle fat are more susceptible to damage in the small blood vessels of the heart, which increases the risk of heart attacks and heart failure.
Intermuscular fat can be found in most muscles in the body, but the amount of fat can vary widely between different people. In our research, we analyse muscle and different types of fat to understand how body composition can influence the small blood vessels or ‘microcirculation’ of the heart, as well as future risk of heart failure, heart attack and death," Prof. Taqueti emphasised.
The study involved 669 Brigham and Women's Hospital patients diagnosed with chest pain and shortness of breath. The average age of participants was 63, and the majority were women. The research found that for every 1% increase in muscle fat fraction, the risk of coronary microvascular dysfunction (CMD) increased by 2%, and the risk of serious heart disease increased by 7%, irrespective of other known risk factors and BMI.
Individuals with high levels of intramuscular fat and evidence of CMD were particularly at risk of death, heart attacks, and heart failure.
Scientists: BMI is not relevant here
Prof. Taqueti emphasises that intramuscular fat can contribute to inflammation and impaired glucose metabolism, leading to insulin resistance and metabolic syndrome. These chronic damages can affect the heart's blood vessels. Understanding the impact of intramuscular fat on heart health can help identify individuals at high risk, irrespective of their BMI.
Research suggests that people with a higher percentage of lean muscle mass have a lower risk of heart disease. Conversely, subcutaneous fat does not increase this risk. Prof. Taqueti and her team are investigating the impact of different treatment strategies, such as exercise, diet, or weight-loss medications, on body composition and heart health.
These findings may be crucial for understanding the impact of new therapies on heart health. However, it remains unknown how to lower the risk in individuals with fatty muscles effectively. Research on this issue is ongoing.
