WINSTON-SALEM, N.C. -- Physicians at Wake Forest University Baptist Medical Center reported today the first demonstration of a gene-diet interaction that affects the absorption of cholesterol in humans.
Richard B. Weinberg, M.D., professor of internal medicine and head of the section on gastroenterology reported at the American Heart Association meeting that the demonstration could eventually pave the way for individualized diet prescriptions.
For several years, Weinberg has been studying a common genetic variant of a standard protein in the blood that appears to protect the people who have it from excess dietary cholesterol.
In the current study, Weinberg and his colleagues reported, "The amount of cholesterol our subjects absorbed was controlled by the type of fat in the diet and whether or not they carried the variant gene. Subjects with the apo A-IV-2 (the scientific name for the variant gene) absorbed much less cholesterol than the 'normal' subjects."
He said about 15 percent of the population carry the apo A-IV-2 gene; most of the rest have the apo-A-IV-1 gene. In the current study, the subjects, mostly medical students and staff members of the Wake Forest University Baptist Medical Center, were tested with three high cholesterol diets, varying the amounts of saturated fat or polyunstaurated fat.
The investigators compared people with the normal gene to people with the variant gene on each of the three diets.
One diet had 35 percent of the daily calories from fat, and 15 percent of total calories were from saturated fat. The second diet also had 35 percent of the calories from fat, and 15 percent of total calories from polyunsaturated fat. The third high-cholesterol diet was low fat, with only 20 percent of the calories from fat, and the fat was made up of equal amounts of saturated fat, polyunsaturated fat (such as vegetable oil) and monounsaturated fat (such as olive oil).