Hidden Fat May Be Fueling Rapid Aging And Disease

Visceral fat is dangerous to your health and is linked to a number of health conditions including metabolic disturbances, Type 2 diabetes, insulin resistance, and an increased risk of cardiovascular disease. Interestingly enough, visceral fat is actually easier to lose than subcutaneous fat because the body metabolizes it quicker, and your body can eliminate it as sweat or urine. However, most people haven’t even heard of this hidden fat.

The dangers of IMAT have been overlooked for too long

"Everyone knows the dangers of belly fat, and how a build-up fat in your cardiac arteries can cause a heart attack. But there is a type of fat that barely anyone has heard of, despite it being linked to a whole range of life-threatening diseases," says Lead author Dr. Osvaldo Contreras, of the Victor Chang Cardiac Research Institute.

"IMAT is crucial for maintaining muscle function, but in common with other fats, too much of it can be a bad thing. Excessive IMAT deposition can trigger muscle atrophy, diminished functional capacity, inflammation, insulin resistance, cardiovascular diseases, metabolic disorders, and even accelerate the ageing process,” explains Dr. Contreras. 

Exploring the hidden fat

This study explored how the accumulation of this hidden fat called intermuscular adipose tissue (IMAT) and its associated cells can promote a range of diseases such as muscle loss, cardiovascular disease, and type 2 diabetes, and it outlines the implications of IMAT which is located between muscle fibers and muscle groups. 

Around 30-40% of adult body mass is made up of skeletal muscles, and they play roles in regulating metabolism, breathing, body temperature, and physical activity. The researchers outline how an accumulation of fibro-adipogenic progenitor (FAPs) cells leads to an increase in IMAT which can result in nerve-to-muscle connections being damaged. 

This chronic damage and disease-modifying factors can promote a wide range of diseases such as type 2 diabetes, cardiovascular disease, and muscle atrophy. IMAT buildup can be caused by several factors such as sex-related hormone levels, an unhealthy lifestyle, and chronic injuries. 

How do we get rid of IMAT?

Unfortunately, there is no simple way to test for levels of IMAT within the muscle. The researchers hope that in the future, advancements in molecular and imaging assessments, along with targeted biopsies will lead to improved diagnostic tools. 

While the exact molecular pathways regulating the switch from muscle support to fat-storing remain unclear, the researchers suggest that over-accumulation of IMAT can be prevented and reversed through regular exercise and eating a healthy diet. The study also points to drugs such as metformin having the potential to address IMAT accumulation and mitigate tissue damage. 

"While the importance of exercise is often emphasised, its critical role in combating frailty and a myriad of diseases is often overlooked," adds Dr. Flores-Opazo, of the Institute of Health Sciences, Universidad de O'Higgins, Chile, and the study's first author. "Regular exercise, including weight training, is imperative for maintaining muscle health and resilience."

"We are hopeful that a deeper understanding of IMAT biology and better testing will pave the way for novel therapeutic strategies targeting various debilitating conditions. We believe this study represents a remarkable step forward in our understanding of human physiology and pathophysiology,” Dr Contreras adds.