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MONDAY, Aug. 11, 2003 (HealthDayNews) -- Can a simple daily regimen of vitamins help children with high cholesterol avoid heart disease later in life?
A small study had found that, for children with inherited disorders causing them to have elevated cholesterol levels, adding the antioxidant vitamins C and E enhanced the functioning of the blood vessels.
"This offers a little promise because it shows that vitamins can somehow help the blood vessels open up, or dilate," says study author Marguerite M. Engler, a professor of physiological nursing at the University of California at San Francisco. "If you do that, you may be able to prevent heart disease early in adulthood."
Others are not so sure.
"It's a provocative study, but the conclusion that antioxidant therapy would restore endothelial function is pure speculation," says Dr. Edward Fisher, a professor of medicine and pediatrics at the Mount Sinai School of Medicine in New York City. "The quality and quantity of evidence in this study to make us even think of recommending that children with elevated cholesterol should increase antioxidant consumption is not there."
The findings, which appear in the Aug. 11 online edition of Circulation and the Sept. 2 print issue of the journal, are the first to come out of the EARLY (Endothelial Assessment of Risk from Lipids in Youth) trial, which is looking at dietary interventions and cardiovascular health in children.
Some 50 million children have excessively high levels of LDL ("bad") cholesterol, which puts them at risk for future heart attacks. These children, most of whom have some type of inherited disorder, are usually treated with diet rather than prescription drugs because of their young age.
High cholesterol is associated with endothelial dysfunction, which in turn seems to presage atherosclerosis and future heart disease. The endothelium is the inner lining of the blood vessels.
Oxidation of LDL cholesterol contributes to the buildup of fat in the arteries (atherosclerosis), which in turn can lead to heart attacks and strokes. Theoretically, antioxidants should counter this process.
Although the authors of the study say prior research suggests antioxidants do reduce the risk of coronary artery disease, others question this premise.
"Certainly the role of antioxidants in preventing heart disease is quite controversial and, if anything, strong data is saying it has a neutral effect or negative," Fisher says. "There's this paradox that, on theoretical grounds, antioxidants should be protective, but in fact there is really no strong epidemiological evidence to support that."
Engler's research team looked at 15 children (seven girls and eight boys), aged 9 to 20, who had one of two different inherited cholesterol disorders. "We were already seeing evidence of endothelial dysfunction," Engler says.
All of the participants followed the National Cholesterol Education Program Step II diet for the entire six months of the study.
After an initial six-week period, the participants were randomly assigned to receive either 500 milligrams of vitamin C and 400 international units of vitamin E per day or placebos for the next six weeks. They stopped the vitamins for six weeks and then reversed the assignments for the final six weeks.
The diet had no effect on endothelial dysfunction, although it did reduce LDL cholesterol by 8 percent.
The vitamin supplements, however, improved endothelial function to almost normal levels.
Measuring endothelial function may not be the most reliable indicator, however. Studies have shown that very small actions will change endothelial measurements. "You can drink a milk shake at McDonald's and it changes that number," says Fisher. "The relationship between short-term change and endothelial reactivity measured with this technique to risk of heart disease is not well established."
More information
For more on lowering cholesterol, visit the National Cholesterol Education Program. The American Academy of Family Physicians has information on lowering cholesterol in kids.
