Not all fat is created equal. Compared to people who accumulate fat in the hips and thighs, people who store fat in their stomachs run a much higher risk of cardiovascular disease, diabetes and other obesity-associated health issues.
In a paper recently published in the international, peer-reviewed journal PLoS ONE, Concordia University’s Sylvia Santosa, assistant professor in the Department of Exercise Science, shows that low testosterone levels lead to changes in fat cells in the lower body but not in the upper body.
The study sheds light on how testosterone controls where fat is stored, and reveals that men who have low levels of testosterone show a shift in how they store body fat. Like women, they store more fat in their hips and thighs.
To prove this, Santosa and co-author Michael Jensen, from the Mayo Clinic in Minnesota, analyzed the amount of stored fat that comes directly from food consumption by giving male study subjects a liquid meal with a radioactive tracer.
They later collected samples of fat from the abdomen and the thigh to see how much of the fat contained in the meal was stored. They found that men with low testosterone stored more fat in the thigh than men with normal testosterone.
Santosa and Jensen also analyzed some of the proteins that break fat down and store it. They found that abnormal protein levels provided clues as to how the presence of testosterone changes the functioning of fat cells.
It turns out that the levels of a protein involved in trapping fat within cells were much higher in the thigh cells of men with low testosterone levels, suggesting that testosterone controls body fat distribution by influencing the proteins that trap fat.
These findings can serve as a warning sign for many. While those with lower body fat are at less risk for diseases associated with obesity than those with upper body fat, those with low testosterone may have an imbalance in their fat-storage system, which can lead to unhealthy cells.
“The main focus for researchers right now is to understand why people are shaped the way they are,” says Santosa. “It’s only through this knowledge that we can progress to treatment and prevention.”
Partners in Research: This study was supported by funding from the National Center for Research Resources, the National Institutes of Health, the American Diabetes Association, the Natural Sciences and Engineering Research Council of Canada and the Canadian Diabetes Association.