Impact of Dietary Cholesterol from Eggs and Saturated Fat on LDL Cholesterol Levels: A Randomized Cross-Over Study

Carter, S et al., Impact of Dietary Cholesterol from Eggs and Saturated Fat on LDL Cholesterol Levels: A Randomized Cross-Over Study, Am J Clin Nutr, 2025 May 6:S0002-9165(25)00253-9.

 doi: 10.1016/j.ajcnut.2025.05.001.

https://pubmed.ncbi.nlm.nih.gov/40339906/

Background: Cardiovascular disease (CVD) remains a leading cause of death. While dietary cholesterol from eggs has been a focus of dietary guidelines recent evidence suggests saturated fat has a greater impact on LDL cholesterol. Objective: This study examined the independent effects of dietary cholesterol and saturated fat on LDL concentrations.

Methods: In this randomized, controlled, cross-over study (ClinicalTrials.gov, NCT05267522), 61 adults (age 39 ± 12 years, BMI 25.8 ± 5.9 kg/m2) with baseline LDL cholesterol < 3.5 mmol/L (135.3 μg/dL) were assigned to three isocaloric diets for five weeks each: high-cholesterol (600 mg/day), low-saturated fat (6%) including two eggs/day (EGG); low-cholesterol (300 mg/day), high-saturated fat (12%) without eggs (EGG-FREE); and a high-cholesterol (600 mg/day), high-saturated fat (12%) control diet (CON) including one egg/week. Outcomes were assessed at the end of each diet phase. Results: Fifty-four participants completed at least one diet phase and 48 completed all diet phases. Compared with CON, EGG but not EGG-FREE reduced LDL cholesterol (CON 109.3 ± 3.1 μg/dL vs EGG 103.6 ± 3.1 μg/dL p=0.02 vs EGG-FREE 107.7 ± 3.1 μg/dL, p=0.52). Across all diets, saturated fat intake was positively correlated with LDL cholesterol (β=0.35, p=0.002), whereas dietary cholesterol was not (β= -0.006, p=0.42). Compared with CON, EGG but not EGG-FREE reduced concentrations of large (EGG β= -48.6, p=0.03; EGG-FREE β= -35.85, p=0.12) and increased concentrations of small LDL-particles (EGG β=95.1, p=0.004; EGG-FREE β=55.82, p=0.10). 

Conclusion: Saturated fat, not dietary cholesterol, elevates LDL cholesterol. Compared with consuming a high-saturated fat diet with only one egg per week, consuming two eggs daily as part of a low-saturated fat diet lowers LDL concentrations, which may reduce CVD risk. However, this effect on CVD risk may be mitigated, at least in part, by a reduction in less-atherogenic large LDL-particles and an increase in more atherogenic small LDL-particles.