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As for the weight loss, "any weight loss is better than no weight loss -- and at least they didn't gain weight," Moore says. "But I'm interested in the fact that CLA is found naturally in certain foods [like beef, lamb, and dairy products]. Do we really need to take a supplement?"
Regarding other risk factors:
The CLA pill group had slightly higher LDL "bad" cholesterol.
The CLA syrup group had slightly lower HDL "good" cholesterol.
Both CLA groups had higher lipoprotein levels, a marker of inflammation and heart disease.
Both CLA groups had higher levels of leptin, a hormone thought to be a heart disease marker.
Both CLA groups had higher white blood cell counts, which could trigger damaging artery inflammation.
The CLA groups had only modest changes in blood sugar levels, a marker for diabetes.
Few volunteers dropped out of the study, indicating that the CLA supplements had no bothersome side effects, reports Gaullier.
"The results of this study corroborate and expand on the findings of the previous short-term studies," he writes. His results show that "the effect is greatest in those with highest body mass index," especially women with a 25 to 30 BMI.
'Normal' Changes in the Body
As far as the heart disease risk factors, the variations seen in the CLA groups "are within normal physiological range," Gaullier tells WebMD. Increased white blood cells may reflect the heightened immune response that other studies have shown. In studies in Holland, CLA has been shown to prevent some viral infections.
"CLA has also shown promise in animal studies in preventing atherosclerosis [hardening of the arteries]," he says.
The increased lipoprotein levels may be a byproduct of fat loss, says Gaullier. "The body does show inflammation caused by the process of eliminating fat. We think this is what is happening, but we don't know for certain."
"The mechanism(s) by which CLA decreases body fat mass and increases lean muscle mass is not completely understood," he writes. "CLA is known to accumulate in tissues of animals and humans where it is readily metabolized." CLA may trigger fat cell death, shrink fat cells, or it may speed up metabolism to promote weight loss, he explains.
SOURCES: Gaullier, J. American Journal of Clinical Nutrition, June 2004. Cindy Moore, MS, RD, director of nutrition therapy, The Cleveland Clinic; spokeswoman, American Dietetic Association. WebMD Medical News: "Supplement Can Help Manage Both Weight and Diabetes."