Twelve healthy volunteers with the Apo-A-IV-1 gene and twelve healthy volunteers who instead have the Apo-A-IV-2 gene each consumed a standard diet supplemented daily by a high-cholesterol food  A high level of cholesterol in the blood is associated with an increased risk of heart disease
After three weeks, the blood cholesterol levels of the subjects in the second group were unchanged, whereas the blood cholesterol levels of those with the Apo-A-IV-1 gene rose 20 percent
The presence of the Apo-A-IV-2 gene may inhibit the elevation of blood cholesterol.