Dietary Cholesterol Contained in Whole Eggs Is Not Well Absorbed and Does Not Acutely Affect Plasma Total Cholesterol Concentration in Men and Women: Results from 2 Randomized Controlled Crossover Studies

Abstract

Whole egg is a food source of dietary cholesterol and inconsistent research findings exist about the effect of dietary cholesterol from whole egg on blood cholesterol concentration. We assessed the effect of co-consuming cooked whole egg (CWE) on dietary cholesterol absorption from two randomized-crossover studies. For study 1, 16 men consumed raw vegetables with no egg, 75 g CWE, or 150 g CWE. For study 2, 17 women consumed cooked vegetables with no egg or 100 g CWE. Triacylglycerol-rich lipoprotein fractions (TRL) were isolated from collected blood. In study 1, total-cholesterol areas under the curve (AUC)_0⁻10h in TRL were not different but triacylglycerol AUC_0⁻10h in TRL was greater for 150 g CWE vs. 75 g CWE and no egg. Similarly, in study 2, total-cholesterol AUC_0⁻10h in TRL was not different but triacylglycerol AUC_0⁻10h in TRL was greater for 100 g CWE vs. no egg. In both studies, whole egg consumption did not affect plasma total-cholesterol AUC_0⁻10h, while triacylglycerol AUC_0⁻10h was increased. These results suggest that the dietary cholesterol in whole egg was not well absorbed, which may provide mechanistic insight for why it does not acutely influence plasma total-cholesterol concentration and is not associated with longer-term plasma cholesterol control.

Keywords: dietary cholesterol; total cholesterol; triacylglycerol; triacylglycerol-rich lipoprotein fractions; whole egg.

Figure 1

Consolidated Standards of Reporting Trials flow diagrams for study 1 and study 2.

Figure 2

Total cholesterol and triacylglycerol AUC_0–10h within TRL fractions in study 1. Values are lsmean ± SE and different superscript letters (a, b) indicate statistical differences among no egg, 75 g CWE, and 150 g CWE (p = 0.0006). AUC, areas under the curve; CWE, cooked whole egg; N/S, not significant; TRL, triacylglycerol-rich lipoprotein.

Figure 3

Total cholesterol and triacylglycerol AUC_0–10h within TRL fractions in study 2. Values are lsmean ± SE and different superscript letters (a, b) indicate statistical differences between no egg and 100 g CWE (p < 0.0001). AUC, areas under the curve; CWE, cooked whole egg; N/S, not significant; TRL, triacylglycerol-rich lipoprotein.

Figure 4

Total cholesterol and triacylglycerol AUC_0–10h within plasma in study 1. Values are lsmean ± SE and different superscript letters (a, b) indicate statistical differences among no egg, 75 g CWE, and 150 g CWE treatments (p = 0.0099). AUC, areas under the curve; CWE, cooked whole egg; N/S, not significant.

Figure 5

Total cholesterol and triacylglycerol AUC_0–10h within plasma in study 2. Values are lsmean ± SE and different superscript letters (a, b) indicate statistical differences between no egg and 100 g CWE treatments (p = 0.0281). AUC, areas under the curve; CWE, cooked whole egg; N/S, not significant.