(OR10-05-25) Effect of Dietary Saturated Fat and Cholesterol From Eggs on LDL-C and Other Blood Lipids: Results of a Randomized Controlled Trial

Objectives: Recent evidence suggests that saturated fat rather than dietary cholesterol intake is related to adverse changes in blood lipids. Eggs are rich in cholesterol and this study aimed to determine the independent effects of dietary cholesterol (including eggs) and saturated fat intakes on blood lipids.

Methods: In this randomized, controlled, cross-over trial, 61 adults (age 39 ± 12 years, BMI 25.8 ± 5.9 kg/m², LDL-C < 135 µg/dL) consumed three isocaloric diets for five weeks each: (1) a high-cholesterol, high-saturated fat control diet including one egg/week (CON); (2) a high-cholesterol, low-saturated fat diet including two eggs/day (EGG); (3) a low-cholesterol, high-saturated fat diet without eggs (EGG-FREE). Dietary intake and blood lipids were measured after each diet phase. Treatment effects were analysed using linear mixed effects models.

Results: Forty-eight participants completed all diet phases. Saturated fat intake was ~14% of energy for CON and EGG-FREE compared with 8% for EGG. Cholesterol intake was 594 mg/day for EGG, 520 mg/day for CON and 300 mg for EGG-FREE. Compared with CON LDL-C was lower with EGG (103.6 ± 3.1 µg/dL vs. 109.3 ± 3.1 µg/dL, p = 0.02), but EGG-FREE was not different (107.7 ± 3.1 µg/dL, p = 0.52). Compared with CON ApoB concentrations were lower with EGG (92.7 ± 2.2 µg/dL vs. 97.4 ± 2.2 µg/dL, p = 0.006) but not different with EGG-FREE (94.6 ± 2.2 µg/dL, p=0.11). Saturated fat intake was positively associated with LDL-C (β = 0.35, p = 0.002) and ApoB (β = 0.21, p = 0.008) but cholesterol intake was not (LDL-C, β = - 0.006, p = 0.42; ApoB, β = - 0.001, p = 0.84). Compared with CON LDL particle size was smaller with EGG (B = -0.10, p=0.02) but not with EGG-FREE (B= -0.03, p=0.56). HDL-C concentrations did not differ between diets (p >0.25), but compared with CON HDL sub-species H4 was lower with EGG (B= -0.41, p=0.02) but not different with EGG-FREE (p=0.27). H4 level was not associated with cholesterol intake (p=0.26) but was associated with saturated fat intake (B = 0.02. p=0.02).

Conclusions: Saturated fat, not dietary cholesterol intake drives elevated LDL-C and ApoB. While LDL-C and ApoB were lower with the EGG diet suggesting a reduction in cardiovascular disease risk, LDL-C particle sizes were smaller and the H4 subfraction of HDL-C was reduced, which may mitigate some of the risk reduction.

Funding Sources: Egg Nutrition Center, a Division of the American Egg Board