Weight Loss Alone May Lower Risk of Heart Disease
Lowers levels of dangerous inflammatory molecule
MONDAY, Feb. 4, 2002 (HealthDayNews) -- Weight loss alone might improve your odds against getting heart disease, a new study suggests.
Overweight people who take the pounds off can reduce blood levels of C-reactive protein, an inflammatory molecule that has been linked to an increased risk of heart attack and stroke, researchers report.
A group of 61 obese women who were guided through a year-long weight reduction program and lost an average of 33 pounds also reduced their blood levels of C-reactive protein by almost a third, says an article in tomorrow's issue of Circulation.
"The link between obesity and C-reactive protein was suspected from the results of other studies," says Andre Tchemof, who led the study while at the University of Vermont. "We demonstrated that creating a weight loss reduced this risk factor."
The key was losing fat, Tchemof says. The women lost an average of more than six pounds of muscle, but "the loss of muscle mass was not related to the change in C-reactive protein," he says. "It really looks like fat loss is the best predictor of C-reactive protein changes."
Earlier studies have shown that fat cells release interleukin-2, a factor that stimulates C-reactive protein production by the liver, Tchemof says. The women averaged a fat loss of more than 20 pounds. While they reduced abdominal fat by more than a third, "total body fat loss was a better predictor of plasma C-reactive protein changes than abdominal fat loss," he says.
C-reactive protein has gained attention because of studies indicating that heart attacks and stroke might be due in part to inflammation that leads to blockage of the arteries. However, weight loss carries additional risk reduction benefits, Tchemof says. For example, there was an increased level of sensitivity to insulin, which is known to be beneficial.
Carolyn Mold, who is doing basic research on C-reactive protein, cautions the case against it as a risk factor for cardiovascular disease is not proven.
Studies in her laboratory show that C-reactive protein interacts with receptors in a number of different cell types, says Mold, who is a professor of molecular genetics and microbiology at the University of New Mexico.
"Some of them are pro-inflammatory, and some are not," she says. "It could be that C-reactive protein is an indicator of the inflammation that is associated with heart disease, rather than being causal. I tend to lean toward the indicator theory."
Whatever its role in heart disease, it's hard to say how much fat must be lost to achieve a clinically important reduction of C-reactive protein levels, Tchemof says. One previous study found that a six-pound loss had no effect. "It's somewhere between 3 kilograms and 15 kilograms," he adds.
In addition, he has a familiar lament: "Everybody can induce weight loss, but it seems harder to have subjects maintain lower weight after that weight loss."
An informal follow-up found a number of the women had gained back all the lost weight, Tchemof adds.
"How to maintain weight loss is a really critical question," he says.
What To Do
The study adds weight to the advice about following a sensible diet and using physical activity to keep weight under control.