Cutting Back on Fat Is Safe for Kids
Things got a little murkier later on. At their five-year follow-up, the difference in cholesterol levels between the two groups seemed to level off. Both groups of children had lower levels of LDL and total cholesterol than when the study began, but now their levels were almost the same. And at the seven-year follow-up, LDL cholesterol had increased slightly, and again, the researchers found little difference between the two groups.
The results are still encouraging, though. The lack of difference at five and seven years may have been due to reduced compliance with the reduced-fat program, says Andrew Tershakovec, MD. "But when they looked specifically at a group of kids who really stayed with the program, then there was more of an effect."
He says that the unrestricted group had better cholesterol levels than expected, "which may have also accounted for the lack of difference at the last follow-up." Tershakovec, who was not involved in the study, is director of the Lipid-Heart Clinic at Children's Hospital of Philadelphia.
Obarzanek points out that going through puberty causes a natural decline in LDL levels. And the small increase at the end of the study may have been due to the adolescents entering adulthood.
The average age at the end of the seven years was 17, she says, and this is the beginning of their LDL level approaching adulthood levels. "We know that adult levels of LDL levels are higher than children's, so there will be a natural rise no matter what we do.
"But the idea is to make the rise a little bit smaller than what it would have been ordinarily," she says.
High-density lipoprotein or HDL cholesterol, the "good" cholesterol, remained similar between the two groups throughout the study. The lower-fat diet did not appear to affect its levels.
However, Gregory Miller, PhD, who is vice chairman of nutrition research at the National Dairy Council in Rosemont, Ill., is concerned about how these study results can be applied to real life.
"They say that it's safe to put kids on a low-fat diet when they're closely followed by pediatricians and nutritionists and are getting a lot of dietary advice on a regular basis," he says, "But this might not work in the real world.