45 middle-aged, mildly hypercholesterolemic subjects, 15 each in APOE E3/3, E3/4, and E4/4 groups matched for sex/age/BMI/menopausal status/baseline cholesterol, followed a fixed sequence of 3 diets: a standardized baseline diet (38% fat, 300 mg cholesterol/d), a modified NCEP-style diet (34% fat, 265 mg cholesterol/d), then that diet plus added cholesterol (566 mg/d). The E4/4 group showed both the largest cholesterol-lowering response to the low-fat/low-cholesterol diet (-14.1%) and the largest rise when cholesterol was added back (+10.4%) — i.e., E4/4 carriers were the most diet-responsive in both directions.
relevance_note: Directly supports “ApoE4 carriers respond more” for dietary cholesterol specifically — in direct tension with Weggemans/Zock 2001’s null finding on the same question; the two anchor ApoE studies for this thread disagree, which the graph needs to carry forward rather than average away.