Historically, nutrition guidelines for reducing the risk of cardiovascular disease (CVD) have included recommendations to limit dietary cholesterol. However, the 2015–2020 Dietary Guidelines for Americans did not issue explicit guidance for dietary cholesterol intake due to inconsistencies in the evidence base. Does this mean eggs can be on the breakfast menu every day without raising CVD risk?
Eggs are a relatively inexpensive and nutrient-dense food. They are a high-quality source of protein and rich in choline, vitamin B2, and the carotenoids lutein and zeaxanthin. They also contain a notable amount of cholesterol: about 186 mg per large egg.
Evidence from randomized controlled trials (RCTs) demonstrates that foods high in cholesterol increase low-density lipoprotein cholesterol (LDL-C), which increases the risk of CVD. More specifically, it’s reported that the consumption of more than 1 egg per day increases LDL-C by about 7.7 mg/dL (0.2 mmol/L), with similar effects in healthy people and people with dyslipidemia.
Nonetheless, studies report the average response and the individual response to dietary cholesterol is highly variable. It appears that the majority of people are able to roughly maintain LDL-C in response to an increase in dietary cholesterol intake. This lack of response is due to a combination of suppression in endogenous cholesterol synthesis, a reduction in dietary cholesterol absorption, and an increase in biliary excretion of cholesterol.
On the other hand, there is a notable subset of individuals who, partly due to genetic differences, lack these feedback control mechanisms and experience a significant increase in LDL-C in response to increases in dietary cholesterol intake (i.e., hyper-responders). In this population, it may be particularly worthwhile to limit egg consumption to prevent LDL-C from rising to an unhealthy level.
For many people, moderate egg consumption is permissible and possibly even beneficial as part of an otherwise healthy diet. However, hyper-responders and people with high cholesterol or dyslipidemia may benefit from limiting their egg consumption or removing eggs from the diet altogether, as this can lead to a clinically meaningful decrease in LDL-C.