Genes Steer Your Cholesterol Ship
Dec. 5, 2000 -- If you're like a lot of Americans, you probably could stand to lower your cholesterol. A new study shows that the choice to do so is up to you -- well, sort of. The researchers tell WebMD that genes may have more power than sheer will in the fight against high cholesterol.
"We were looking into why people differ in their response to cholesterol lowering diets," says study leader Margo A. Denke, MD, associate professor of medicine at the University of Texas Southwestern Medical Center in Dallas. "Some people try very, very hard on a diet, but can't even budge their cholesterol levels. We were trying to determine how much of that was due to genetics."
Between 1997 and 1999, 56 families -- 92 adults and 134 children -- in the Dallas-Ft. Worth area followed two special diets.
During the study, all members of a family got their fat -- 20-25% of total calories -- in the form of either saturated fat-laden butter or margarine with unsaturated fat. For each regimen, families were provided with specially formulated breads, baked snacks, and spreadable fat for cooking. After five weeks, they went back to their normal diet for a month, then switched to the other diet for five more weeks. Cholesterol levels were measured at different intervals during the study.
The research -- which, luckily for the study participants, was halted between Thanksgiving and Christmas each year -- is published in the Dec. 6, 2000 issue of The Journal of the American Medical Association.
"In our study, 80% of people had lower cholesterol levels when they consumed margarine compared to butter," Denke, who is also at the UT Southwestern's Center for Human Nutrition, tells WebMD. Although the overall trend was for cholesterol levels to drop with less saturated fat intake, genetics definitely played a role. Parents who responded -- whose cholesterol went up and down with diet -- had children who responded as well. "And if the parents don't respond, neither do the children," she says.
People are powerless over their genes but one take home message "is that margarine is a better choice than butter, which is one of the most potent cholesterol-raising fats," says Denke. There is increasing evidence, including a recent study looking at the blood vessels of children who'd died in car accidents, that plaques that clog blood vessels begin forming much earlier than previously thought. "What you eat really is very important," she says, "and it is especially important to start out right. There will be big pay-offs as you get older for learning a good diet when you're young."