A genetic mutation found in a small group of people might protect their heart against the effects of a high-fat diet. More specifically, the gene mutation speeds up the breakdown of triglycerides, those fats that clog arteries. The researchers say the gene variant is rare in the general population.

The researchers at the Maryland School of Medicine used blood samples from 800 volunteers in the Old Order Amish community to search for genes that might be associated with levels of fat particles called triglycerides in the blood stream. They gave the participants a super-high-fat milk shake (78 percent of calories from fat), and then monitored them for the next six hours. The researchers used blood samples to measure how much fat was churning through their bloodstreams.

They found that individuals with a mutation in the APOC3 gene, which encodes a protein, called apoC-III, that inhibits the breakdown of triglycerides, had the lowest blood tryclyceride levels. Those with the mutation had higher levels of “good” HDL-cholesterol and lower levels of “bad” LDL-cholesterol, the researchers reported Thursday in the journal Science. Their levels of artery-hardening were relatively low, which means they were less likely to develop cardiovascular disease.

The findings raise “the possibility that therapies aimed specifically at down-regulating APOC-III expression will be clinically efficacious and safe in reducing the morbidity and mortality associated with coronary heart disease,” the researchers report. Dr. Toni Pollin, Ph.D., of the University of Maryland School of Medicine, says that she and her colleagues will conduct more studies to better understand the physiology of APOC3 gene and related pathways.