By Emma Hitt, PhD
ATLANTA, Jan 14 (Reuters Health) - Obese people may lower their heart disease risk by losing a moderate amount of weight, as shedding pounds appears to cut blood levels of proteins involved in inflammation, according to Italian researchers.
Obesity, a burgeoning problem in many developed nations, is a major risk factor for heart disease. Abdominal fat, in particular, is linked to an increased risk of cardiovascular disease.
Weight gain, especially around the abdomen, is also known to increase levels of immune system proteins called cytokines. Certain cytokines cause an inflammatory response, which can contribute to the formation of fatty deposits in the arteries known as atherosclerosis.
In the new study, a team led by Dr. Dario Giugliano from the Second University of Naples, Italy, wanted to see what effect weight reduction might have in reducing levels of circulating cytokines in obese individuals.
The researchers recruited 56 healthy obese women aged 25 to 44. At the beginning of the study, they compared the obese women with 40 normal-weight women of similar age.
The investigators found that obese women had increased levels of two cytokines--called tumor necrosis factor-alpha and interleukin 6--as well as increased expression of atherosclerosis-promoting proteins that are known to be triggered by increased cytokine levels.
After one year on a program of diet, exercise and behavioral counseling, each of the obese women lost at least 10% of their starting weight (about 22 pounds, on average). They also showed a significant reduction in their levels of cytokines and other potentially damaging proteins.
"Weight loss represents a safe method for downregulating the inflammatory state and ameliorating (blood-vessel) dysfunction in obese women," the researchers conclude in the January 15th issue of Circulation: Journal of the American Heart Association.
"This is the first study evaluating the effect of sustained long-term weight loss on cytokine levels in obese women," Giugliano told Reuters Health.
Giugliano pointed out that cytokine levels returned toward normal values, even though women did not lose all their excess weight.
"This is reassuring," he said, pointing out that the findings indicate that obese people need not reach a normal weight to reduce their heart risks. Instead, Giugliano said, losing around 10 to 20 pounds could make a difference.
"The past two decades have seen an explosive increase in both obesity and diabetes," Giugliano said. "So, it is reassuring that lifestyle changes may...reduce rates of cardiovascular events."
SOURCE: Circulation 2002;105.
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