Abdominal fat packed deep between the organs is directly linked to colon cancer, according to a new animal study.
The study, published in the journal Cancer Prevention Research, shows the direct impact of abdominal, also known as visceral, fat.
"There has been some skepticism as to whether obesity per se is a bona fide cancer risk factor, rather than the habits that fuel it, including a poor diet and a sedentary lifestyle," study researcher Derek M. Huffman, Ph.D., a postdoctoral fellow at the Institute for Aging Research at the Albert Einstein College of Medicine, said in a statement. "Although those other lifestyle choices play a role, this study unequivocally demonstrates that visceral adiposity is causally linked to intestinal cancer."
The study involved three groups of mice. The first group underwent sham surgery, and ate as much food as they wanted -- which led to them becoming obese. The second group of mice also were allowed to eat as much as they wanted -- also leading to them becoming obese -- but researchers surgically removed the visceral fat from them. The third group of mice underwent sham surgery, but had their calorie intake restricted; because they ate less than the other mice, they had less visceral fat.
Researchers found that the mice that underwent the sham surgery and were allowed to eat as much as they wanted were the ones more likely to have intestinal tumors. Meanwhile, the mice whose visceral fat was surgically removed, as well as the mice whose calories were restricted, were less likely to have intestinal tumors.
There were also differences in the relationship between visceral fat and intestinal tumors, when taking the mouse's sex into account. Specifically, female mice experienced fewer intestinal tumors when their visceral fat was surgically removed, but not when they underwent the calorie restriction and sham surgery. Researchers found that the opposite was the case for male mice.
This is hardly the first time abdominal fat in particular has been pegged to specific health risks, though other studies have shown more correlation-type associations. One study, presented at the annual meeting of the Radiological Society of North America, showed an association between higher amounts of abdominal fat and decreased bone strength in men. Another study, published in the Journal of the American Medical Association, showed an association between abdominal fat and Type 2 diabetes.
And yet another study, presented at a meeting last year of the European Society of Cardiology Congress, showed that people with too much belly fat may have an increased risk of death -- even higher than people who are obese.