Obesity can turn body fat toxic
A lucky few escape the link with disease-causing inflammation, two studies find
By Janet Raloff
Obesity can trigger inflammation in the fat cells found just below the skin, creating an environment that has been linked with the development of both diabetes and heart disease, two new studies indicate.
The findings suggest that people need to worry about all types of body fat, not just the deeply embedded fat that earlier work had focused on. But the new work also hints that some face a higher risk than others.
In the body, most fat clusters under the skin in what’s known as subcutaneous adipose tissue. Much of the rest, called visceral fat, accumulates within muscle and between organs deeper inside the body. For more than a decade, studies have shown that obesity triggers visceral fat to begin spewing hormonelike chemicals called cytokines. These proinflammatory chemicals have been linked with metabolic syndrome, a constellation of abnormalities that can include impaired insulin sensitivity (known as insulin resistance), fat buildup around the waist, high blood pressure and low concentrations of HDL, the good cholesterol.
“There’s been this sort of ill-proven idea that subcutaneous adipose tissue is not harmful and that visceral adipose tissue is the vicious demon that makes us sick,” says Gökhan S. Hotamisligil of the Harvard School of Public Health in Boston, who was not involved in the studies. The new data, he says, reinforce the fact that subcutaneous fat is far from benign.