Article Impact Level: HIGH Data Quality: STRONG Summary of The American Journal of Clinical Nutrition, 122(1), 83–91. https://doi.org/10.1016/j.ajcnut.2025.05.001 Dr. Sharayah Carter et al.
Points
- A recent study suggests that dietary saturated fat, rather than the cholesterol found in eggs, is the primary factor contributing to increased levels of harmful LDL cholesterol.
- Consuming two eggs daily as part of a low-saturated fat diet was shown to lower total LDL cholesterol compared to a high-saturated fat diet with minimal eggs.
- However, the egg-inclusive, low-saturated fat diet also caused a shift in LDL particle composition, reducing larger particles while increasing smaller, more atherogenic LDL concentrations.
- Researchers conducted a randomized, controlled, crossover trial where participants followed three distinct diets for five weeks each to isolate the effects of fat and cholesterol.
- These findings suggest that dietary advice should focus more on limiting saturated fat from foods like bacon, rather than restricting the consumption of cholesterol-rich eggs for heart health.
Summary
A randomized, controlled, crossover study investigated the independent effects of dietary cholesterol and saturated fat on LDL cholesterol concentrations in 61 adults (mean age 39 ± 12 years, mean BMI 25.8 ± 5.9 kg/m²). Participants were assigned to three 5-week isocaloric diets: a high-cholesterol (600 mg/d), low-saturated fat (6%) diet with 2 eggs/d (EGG); a low-cholesterol (300 mg/d), high-saturated fat (12%) diet (EGG-FREE); and a high-cholesterol (600 mg/d), high-saturated fat (12%) control diet (CON). The study aimed to decouple the metabolic impacts of these two dietary components.
Results from the 48 participants who completed all diet phases showed that saturated fat, not dietary cholesterol, was the primary driver of LDL cholesterol. Compared to the high-saturated fat CON diet, the low-saturated fat EGG diet significantly reduced LDL cholesterol (109.3 ± 3.1 μg/dL vs. 103.6 ± 3.1 μg/dL; P = 0.02), whereas the high-saturated fat EGG-FREE diet did not (107.7 ± 3.1 μg/dL; P = 0.52). Across all diets, saturated fat intake demonstrated a significant positive correlation with LDL cholesterol (β = 0.35, P = 0.002), while dietary cholesterol showed no significant correlation (β = −0.006, P = 0.42).
The study concluded that a diet low in saturated fat, even if high in dietary cholesterol from eggs, can lower LDL cholesterol. However, this diet also produced a potentially adverse shift in LDL particle morphology. Compared with the CON diet, the EGG diet significantly reduced concentrations of larger, less atherogenic LDL particles (β = −48.6, P = 0.03) while increasing concentrations of smaller, more atherogenic LDL particles (β = 95.1, P = 0.004). This nuance may mitigate overall cardiovascular risk reduction.
Link to the article: https://www.sciencedirect.com/science/article/abs/pii/S0002916525002539
References Carter, S., Hill, A. M., Yandell, C., Wood, L., Coates, A. M., & Buckley, J. D. (2025). Impact of dietary cholesterol from eggs and saturated fat on LDL cholesterol levels: A randomized cross-over study. The American Journal of Clinical Nutrition, 122(1), 83–91. https://doi.org/10.1016/j.ajcnut.2025.05.001
