Eggs are a nutrient-rich food beloved by people of all ages. However, the relationship between egg consumption and cardiovascular disease risk has long been debated. This article explores the impact of egg intake on all-cause mortality and cardiovascular disease mortality through the latest scientific research, while shedding light on the role of genetic factors. It aims to help readers better understand how to consume eggs in a balanced and healthy way.
Eggs, often hailed as the versatile staple of the kitchen, are also considered the "all-rounder" in the world of nutrition. Loved by people of all ages, they are not only packed with high-quality protein but also rich in vitamin D, choline, and essential amino acids, making them an indispensable part of a balanced diet.
However, due to their versatility, many people may unintentionally consume multiple eggs in a single day. This raises concerns: could the cholesterol in eggs increase the risk of cardiovascular diseases? How many eggs should one eat per day for optimal health?
Latest Research: Moderate Egg Consumption Benefits Health
Recently, a research team from Monash University in Australia published a study in the journal Nutrients. The findings revealed that, compared to those who never or rarely ate eggs, individuals who consumed eggs 1–6 times per week experienced a 15% reduction in all-cause mortality and a 29% reduction in cardiovascular disease (CVD) mortality.
The researchers assessed egg intake through 49 food frequency questionnaires, categorizing participants into three groups: never/rarely (1–2 times per month), weekly (1–6 times per week), and daily (several times per day). The primary endpoints were all-cause mortality, cancer mortality, and CVD mortality.
The study included 8,756 elderly participants with a median age of 76.9 years, 54% of whom were women. Over a median follow-up period of 5.9 years, 1,034 all-cause deaths (11.8%) were recorded, including 453 cancer deaths (5.2%) and 229 CVD deaths (3.2%). The analysis showed that, compared to those who never or rarely ate eggs, weekly egg consumers had a 15% lower risk of all-cause mortality and a 29% lower risk of CVD mortality. However, no significant association was found between egg intake and cancer mortality.
Figure 1: All-cause and cause-specific mortality, total mortality, and frequency of egg consumption
Subgroup analysis indicated that individuals with medium-to-high diet quality who consumed eggs weekly experienced a 33% and 44% reduction in CVD mortality, respectively. For those with dyslipidemia, weekly egg consumption reduced CVD mortality by 27%, while for those without dyslipidemia, the risk was further reduced to 43%.
Figure 2: Association between egg consumption and all-cause and cause-specific mortality in community-dwelling older adults
In summary, moderate egg intake not only does not harm the health of older adults but also helps reduce all-cause mortality and CVD mortality.
Genetic Factors and Egg Intake: A Potential Link to Coronary Artery Disease Risk
However, not everyone is suited to high egg consumption. A prospective cohort study published in The American Journal of Clinical Nutrition found that individuals with higher egg intake and higher polygenic risk scores (PRS) had a significantly increased risk of coronary artery disease (CAD).
This study included 34,111 participants with eligible genetic data and no baseline CAD. The average age of participants was 52.3 years, with 41.8% being male. Over a median follow-up period of 11.7 years, 1,128 CAD cases were reported. The analysis revealed that as egg intake increased, so did the prevalence of hypertension, diabetes, and the risk of CAD.
Figure 3: Additive interaction between egg consumption and genetic risk associated with incident CAD
Using a polygenic risk score (PRS) based on 540 genetic variants, the researchers quantified genetic susceptibility. The results showed that higher egg intake was associated with an increased risk of CAD. Using one egg per week as the reference, the CAD risk ratios were 1.02 for 1–3 eggs per week, 1.05 for 3–6 eggs per week, 1.28 for 6–10 eggs per week, and 1.42 for more than 10 eggs per week. This indicates that CAD risk increases with higher egg consumption.
Notably, the impact of egg intake on CAD risk was more pronounced in individuals with high genetic risk. Specifically, an increase of three eggs per week was associated with a 5% higher CAD risk in individuals with low-to-moderate genetic risk, while the risk increased by 10% in those with high genetic risk.
The researchers conducted a joint analysis of egg consumption and genetic susceptibility, finding that for individuals with low-to-moderate genetic risk, even consuming 10 or more eggs per week did not significantly increase CAD risk. However, for those with high genetic risk (i.e., those in the highest PRS category), consuming 10 or more eggs per week significantly increased CAD risk, with a hazard ratio (HR) of 2.95.
In terms of absolute risk, the 10-year cumulative incidence of CAD increased from 1.37% to 4.24% in high genetic risk individuals who consumed 10 or more eggs per week. This suggests that high egg intake significantly elevates both relative and absolute risks in genetically susceptible individuals.
Figure 4: Joint analysis of egg consumption and genetic risk with incident CAD
Conclusion
In summary, the findings from these two studies suggest that for the general population, consuming an average of one egg per day can significantly reduce all-cause mortality and CVD mortality. However, individuals at higher risk of coronary artery disease, particularly those with high genetic susceptibility, should consider limiting their egg intake.
In daily life, maintaining dietary diversity and balance is crucial. While eggs are a nutritious choice, they should be paired with other foods such as vegetables, whole grains, and lean meats to ensure a well-rounded nutrient intake. By adopting a scientifically balanced diet, we can enjoy the benefits of eggs while safeguarding our health.
