New research shows moderate supplementation of vitamins C and E can slow the progression of hardening of the arteries or atherosclerosis in high-risk children with a genetic risk factor that makes them susceptible to the disease.
The study appears in the Aug. 12 issue of Circulation: Journal of the American Heart Association.
Researchers say it's the first study to show that moderate doses of antioxidant vitamins can reverse endothelial dysfunction, a condition in which the blood vessels aren't flexible enough to expand and contract in response to changes in blood flow. It's also an early sign of atherosclerosis.
Antioxidants Reduce Risks
In the study, researchers followed 15 children and young adults between the ages of 9 and 20 who had a genetic abnormality that leads to childhood onset of high levels of "bad" LDL cholesterol, which is known to increase the risk of heart attacks early in life. They also looked at children with high levels of combined fats- cholesterol and triglycerides.
The participants were put on the National Cholesterol Education Program (NCEP) Step II diet for six months. This diet limits the amounts of total and saturated fats. After six weeks on the diet, the children were randomly assigned to receive 500 milligrams (mg) of vitamin C and 400 international units (IU) of vitamin E or placebos for alternating periods.
Researchers then measured the participants' endothelial function using an ultrasound that detects changes in blood flow in the arm. In particular, researchers calculated changes in the dilation of the artery, known as flow-mediated dilation (FMD). In healthy children, FMD ranges between 8% and 12%, but the FMD among the at-risk children averaged only 5.7% at the start of the study.
After therapy with vitamins C and E and the NCEP diet, the study showed that the children's FMD increased to an average of 9.5%.
Researchers say those results are significant because reduced FMD is an early indicator of heart disease in later life.
"There is evidence from epidemiological studies that diets rich in antioxidants can decrease the risk of coronary artery disease, which is why we decided to look specifically at these high risk children," says researcher Marguerite Engler, PhD, of the University of California at San Francisco, in a news release.
"The dose of vitamin C used in the study can be readily achieved with whole food, but only 20 percent of children consume the recommended five or more servings of fruit and vegetables a day," says Engler. "Rich sources of vitamin E and whole grains and nuts are also deficient in the typical American child's diet."