Location, not volume, of fat found to be key
WFU study finds deposits around organs harmful
By Richard Craver | Journal Reporter
Published: September 10, 2008
A new study by medical researchers at Wake Forest University is adding to the evidence that it may be more important where excess weight is on the body than how much a person has.
The researchers monitored 398 black and white Forsyth County residents -- all between the ages of 47 and 86. They used cardiac and CT scans to measure multiple fat depots in the participants.
They found that the amount of fat a person had deposited around organs and in between muscles had a direct correlation to the amount of hard, calcified plaque that person had.
The researchers said that calcified plaque itself is not considered risky. But it is associated with the development of atherosclerosis, or the presence of less stable, fatty deposits in the blood vessels that can lead to heart attack and stroke.
"We are facing an obesity epidemic, which obviously affects many things -- metabolic abnormalities, cardiovascular disease, etc.," said Dr. Jingzhong Ding, the lead researcher and an assistant professor of gerontology at the medical center.
The dangers of having excessive "belly fat" have been documented for years.
Experts have said that too much weight around the midsection can lead to heart disease, Type 2 diabetes and even some types of cancers in men and women. Some of the risks are genetic, with men more likely to gain weight around their middle and women in the legs and buttocks as they age.
"Our hypothesis was that this kind of fat is quite different from subcutaneous fat, or fat just below the skin," Ding said. "Subcutaneous fat may not be as bad as having fat deposited around organs and in between muscles."
Researchers at Duke University Medical Center published a study in 2005 that focused on the levels of fat around the vital organs of 178 white and minority North Carolinians, all of whom were ages 40 to 65.
The Duke study, published in the Journal of Applied Physiology, found that eight months of inactivity increased visceral fat -- the potentially dangerous layer of belly fat -- by about 9 percent.
Meanwhile, people who exercised vigorously for eight months reduced their visceral fat by 8 percent.
The study also found that continued stress can encourage the buildup of fat around the midsection.
"In our study, the control group that did not exercise saw a sizable and significant 8.6 percent increase in visceral fat in only six months," Cris Slentz, the lead author of the Duke study and an exercise physiologist, said at the time.
"That could equate to a weight gain of approximately 4 pounds per year.
"We also found that a modest exercise program equivalent to a brisk 30-minute walk six times a week can prevent accumulation of visceral fat, while even more exercise can actually reverse the amount of visceral fat."
Ding, in another Wake Forest study published in August, found that fat deposited around the heart is associated with calcified plaque in the arteries, and "therefore may be worse than having a high body-mass index or a thick waist."
"We know that even thin people could have excessive fat" around their vital organs, Ding said. "If this hypothesis is confirmed, we should look for ways to specifically target the fat depot" around organs.
The Wake study was financed by the National Heart, Lung and Blood Institute and the National Institutes of Health. It will be in the September issue of the American Journal of Clinical Nutrition, a publication of the American Society for Nutrition