Consumption of one egg per day reduces the expression of HMG‐CoA reductase in peripheral mononuclear cells (PBMC) to maintain LDL cholesterol concentrations

Abstract

Thirty three subjects (men and women, 40–75 y) were recruited and randomly assigned to consume either 1 egg per day (n = 13) (203 additional mg cholesterol/d) (EGG) or the equivalent amount of egg substitute (n = 9) (0 additional mg cholesterol/d)(SUB) for 12 wk. We isolated plasma and peripheral blood mononuclear cells both at baseline and wk 12 to determine plasma lipids and the expression of genes involved in maintaining plasma LDL cholesterol (LDL‐C) and genes associated with reverse cholesterol transport. Plasma LDL‐C was reduced over time for all subjects in the EGG (134 ± 27 to 129 ± 30 mg/dL) and SUB (127 ± 14 to 113 ± 30 mg/dL) groups (p< 0.05). HDL cholesterol (HDL‐C) was increased by 17% in the EGG (P < 0.05) while no changes were observed in the SUB group. Dietary records indicated that subjects in the EGG were consuming 408 mg cholesterol/d compared to 165 mg in the SUB group. The expression of ATP binding cassette (ABC) AI and ABCG1 transporters or the LDL receptor were not affected over time or by diet. In contrast, the expression of HMG‐CoA reductase was decreased from 2.97 ± 2.7 to 1.37 ± 1.44 to arbitrary units (P<0.025) in the EGG and from 2.5 ± 2.1 to 1.04 ± 0.75 arbitrary units in the SUB group (p <0.025). These results suggest that the observed decreases in LDL‐C in both groups can be associated with a suppression of HMG‐CoA reductase gene expression [supported by the Egg Nutrition Center].