Finished thinking
Myers M, Ruxton CHS.
Nutrients. 2023;15(12):2657. doi:10.3390/nu15122657.
Hen's eggs (from ) provide choline, folate, vitamin D, iodine, B vitamins and high-quality protein and are no longer viewed by national bodies as a risk factor for hypercholesterolaemia and cardiovascular disease (CVD). Yet, questions remain about the benefits and risks of eating eggs regularly. This review evaluates recent high-quality evidence from randomised controlled trials (RCT) and meta-analyses of observational studies and considers new areas of interest, such as weight management, protein metabolism, allergy risk and sustainability. In several RCT, eggs increased muscle protein synthesis and lowered fat mass, which could support optimal body composition. Eggs within a meal improved satiety, which could translate into lower energy intakes, although more RCT are needed. In observational studies, higher egg consumption was associated with a null effect or a modest reduced risk of CVD. For type 2 diabetes (T2D) incidence and risk of CVD in people with T2D, there were inconsistencies between observational and RCT data, with the former noting positive associations and the latter seeing no effect of higher egg intake on markers of T2D and CVD. Sustainability metrics suggest that eggs have the lowest planetary impact amongst animal proteins. To lower allergy risk, earlier introduction of eggs into weaning diets is warranted. In conclusion, the balance of evidence points to eggs being a nutritious food suggesting there are broad health benefits from including eggs in the diet at intakes higher than that currently consumed by European populations.
Zhao B, Gan L, Graubard BI, et al.
Circulation. 2022;145(20):1506-1520. doi:10.1161/CIRCULATIONAHA.121.057642.
Background: Despite substantial research highlighting the importance of exogenous dietary cholesterol intake and endogenous serum cholesterol level in human health, a thorough evaluation of the associations is lacking. Our study objective was to examine overall and cause-specific mortality in relation to dietary and serum cholesterol, as well as egg consumption, and conduct an updated meta-regression analysis of cohort studies.
Methods: We conducted a prospective analysis of 27 078 men in the ATBC Study (Alpha-Tocopherol, Beta-Carotene Cancer Prevention). Multivariable-controlled cause-specific Cox proportional hazards regression models were used to calculate hazard ratios and 31-year absolute mortality risk differences. A systematic review and meta-analysis of cohort studies was also performed (PROSPERO [
Url: https://www.crd.york.ac.uk/prospero/; Unique identifier: CRD42021272756]).
Results: Based on 482 316 person-years of follow-up, we identified 22 035 deaths, including 9110 deaths from cardiovascular disease (CVD). Greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Hazard ratios for each additional 300 mg cholesterol intake per day were 1.10 and 1.13 for overall and CVD-related mortality, respectively; for each additional 50-g egg consumed daily, hazard ratios were 1.06 and 1.09, respectively, for overall and CVD-related mortality (all P values<0.0001). After multivariable adjustment, higher serum total cholesterol concentrations were associated with increased risk of CVD-related mortality (hazard ratios per 1 SD increment, 1.14; P<0.0001). The observed associations were generally similar across cohort subgroups. The updated meta-analysis of cohort studies on the basis of 49 risk estimates, 3 601 401 participants, and 255 479 events showed consumption of 1 additional 50-g egg daily was associated with significantly increased CVD risk (pooled relative risk, 1.04 [95% CI, 1.00-1.08]; I2=80.1%). In the subgroup analysis of geographic regions (Pinteraction=0.02), an increase of 50-g egg consumed daily was associated with a higher risk of CVD in US cohorts (pooled relative risk, 1.08 [95% CI, 1.02-1.14]) and appeared related to a higher CVD risk in European cohorts with borderline significance (pooled relative risk, 1.05), but was not associated with CVD risk in Asian cohorts.
Conclusions: In this prospective cohort study and updated meta-analysis, greater dietary cholesterol and egg consumption were associated with increased risk of overall and CVD-related mortality. Our findings support restricted consumption of dietary cholesterol as a means to improve long-term health and longevity.
Ma W, Zhang Y, Pan L, et al.
The Journal of Nutrition. 2022;152(10):2227-2237. doi:10.1093/jn/nxac105.
Background: Recent studies have reported conflicting associations between egg consumption and the risk of all-cause or cardiovascular disease (CVD) mortality, including ischemic heart disease (IHD) mortality and stroke mortality. With accumulating evidence, up-to-date evidence about the association should be synthesized.
Objectives: We aimed to assess the association of the risk of all-cause and CVD mortality with egg consumption.
Methods: We searched the PubMed, Embase, and Web of Science databases through 3 November, 2021 for observational studies conducted in participants ≥18 y of age and which provided ORs, RRs, or HRs and 95% CIs for ≥3 egg consumption categories or for increased intake of egg addressing the associations of interest. A random-effects model was used to pool the reported risk estimates. Restricted cubic splines were used to examine the dose-response association.
Results: Twenty-four articles with 48 reports (25 for all-cause mortality, 11 for CVD mortality, 6 for IHD mortality, and 6 for stroke mortality) involving 11,890,695 participants were included. Intake of each 1-egg/d increment was associated with increased risk of all-cause mortality (
Rr: 1.06; 95%
Ci: 1.02, 1.10; P = 0.008), but the association was restricted to women, Americans, and studies with adjustments for hyperlipidemia. Egg consumption was linearly associated with CVD mortality only in participants >60 y of age, Americans, studies with follow-up duration ≥15 y, and studies with adjustments for hyperlipidemia (P ≤ 0.018). No significant association was found between egg consumption and IHD or stroke mortality (P ≥ 0.080).
Conclusions: Egg consumption was linearly associated with a modestly increased risk of all-cause mortality and, in older participants, Americans, and studies with longer follow-up or adjustments for hyperlipidemia, CVD mortality. These findings suggest that it may be prudent to avoid high egg consumption.
Zhong VW, Van Horn L, Cornelis MC, et al.
JAMA. 2019;321(11):1081-1095. doi:10.1001/jama.2019.1572.
Importance
Cholesterol is a common nutrient in the human diet and eggs are a major source of dietary cholesterol. Whether dietary cholesterol or egg consumption is associated with cardiovascular disease (CVD) and mortality remains controversial.
Objective
To determine the associations of dietary cholesterol or egg consumption with incident CVD and all-cause mortality.
Design, Setting, and Participants
Individual participant data were pooled from 6 prospective US cohorts using data collected between March 25, 1985, and August 31, 2016. Self-reported diet data were harmonized using a standardized protocol.
Exposures
Dietary cholesterol (mg/day) or egg consumption (number/day).
Main Outcomes and Measures
Hazard ratio (HR) and absolute risk difference (ARD) over the entire follow-up for incident CVD (composite of fatal and nonfatal coronary heart disease, stroke, heart failure, and other CVD deaths) and all-cause mortality, adjusting for demographic, socioeconomic, and behavioral factors.
Results
This analysis included 29 615 participants (mean [SD] age, 51.6 [13.5] years at baseline) of whom 13 299 (44.9%) were men and 9204 (31.1%) were black. During a median follow-up of 17.5 years (interquartile range, 13.0-21.7; maximum, 31.3), there were 5400 incident CVD events and 6132 all-cause deaths. The associations of dietary cholesterol or egg consumption with incident CVD and all-cause mortality were monotonic (all P values for nonlinear terms, .19-.83). Each additional 300 mg of dietary cholesterol consumed per day was significantly associated with higher risk of incident CVD (adjusted HR, 1.17 [95% CI, 1.09-1.26]; adjusted ARD, 3.24% [95% CI, 1.39%-5.08%]) and all-cause mortality (adjusted HR, 1.18 [95% CI, 1.10-1.26]; adjusted ARD, 4.43% [95% CI, 2.51%-6.36%]). Each additional half an egg consumed per day was significantly associated with higher risk of incident CVD (adjusted HR, 1.06 [95% CI, 1.03-1.10]; adjusted ARD, 1.11% [95% CI, 0.32%-1.89%]) and all-cause mortality (adjusted HR, 1.08 [95% CI, 1.04-1.11]; adjusted ARD, 1.93% [95% CI, 1.10%-2.76%]). The associations between egg consumption and incident CVD (adjusted HR, 0.99 [95% CI, 0.93-1.05]; adjusted ARD, −0.47% [95% CI, −1.83% to 0.88%]) and all-cause mortality (adjusted HR, 1.03 [95% CI, 0.97-1.09]; adjusted ARD, 0.71% [95% CI, −0.85% to 2.28%]) were no longer significant after adjusting for dietary cholesterol consumption.
Conclusions and Relevance
Among US adults, higher consumption of dietary cholesterol or eggs was significantly associated with higher risk of incident CVD and all-cause mortality in a dose-response manner. These results should be considered in the development of dietary guidelines and updates.
Zhuang P, Wu F, Mao L, et al.
PLoS Medicine. 2021;18(2):e1003508. doi:10.1371/journal.pmed.1003508.
Background: Whether consumption of egg and cholesterol is detrimental to cardiovascular health and longevity is highly debated. Data from large-scale cohort studies are scarce. This study aimed to examine the associations of egg and cholesterol intakes with mortality from all causes, cardiovascular disease (CVD), and other causes in a US population.
Methods And Findings: Overall, 521,120 participants (aged 50-71 years, mean age = 62.2 years, 41.2% women, and 91.8% non-Hispanic white) were recruited from 6 states and 2 additional cities in the US between 1995 and 1996 and prospectively followed up until the end of 2011. Intakes of whole eggs, egg whites/substitutes, and cholesterol were assessed by a validated food frequency questionnaire. Cause-specific hazard models considering competing risks were used, with the lowest quintile of energy-adjusted intake (per 2,000 kcal per day) as the reference. There were 129,328 deaths including 38,747 deaths from CVD during a median follow-up of 16 years. Whole egg and cholesterol intakes were both positively associated with all-cause, CVD, and cancer mortality. In multivariable-adjusted models, the hazard ratios (95% confidence intervals) associated with each intake of an additional half of a whole egg per day were 1.07 (1.06-1.08) for all-cause mortality, 1.07 (1.06-1.09) for CVD mortality, and 1.07 (1.06-1.09) for cancer mortality. Each intake of an additional 300 mg of dietary cholesterol per day was associated with 19%, 16%, and 24% higher all-cause, CVD, and cancer mortality, respectively. Mediation models estimated that cholesterol intake contributed to 63.2% (95% CI 49.6%-75.0%), 62.3% (95% CI 39.5%-80.7%), and 49.6% (95% CI 31.9%-67.4%) of all-cause, CVD, and cancer mortality associated with whole egg consumption, respectively. Egg white/substitute consumers had lower all-cause mortality and mortality from stroke, cancer, respiratory disease, and Alzheimer disease compared with non-consumers. Hypothetically, replacing half a whole egg with equivalent amounts of egg whites/substitutes, poultry, fish, dairy products, or nuts/legumes was related to lower all-cause, CVD, cancer, and respiratory disease mortality. Study limitations include its observational nature, reliance on participant self-report, and residual confounding despite extensive adjustment for acknowledged dietary and lifestyle risk factors.
Conclusions: In this study, intakes of eggs and cholesterol were associated with higher all-cause, CVD, and cancer mortality. The increased mortality associated with egg consumption was largely influenced by cholesterol intake. Our findings suggest limiting cholesterol intake and replacing whole eggs with egg whites/substitutes or other alternative protein sources for facilitating cardiovascular health and long-term survival.
Trial Registration: ClinicalTrials.gov NCT00340015.
Chen GC, Chen LH, Mossavar-Rahmani Y, et al.
The American Journal of Clinical Nutrition. 2021;113(4):948-959. doi:10.1093/ajcn/nqaa353.
Background: The potential cardiovascular impact of dietary cholesterol intake has been actively debated for decades.
Objectives: We aimed to evaluate associations of dietary cholesterol and egg intakes with incident cardiovascular disease (CVD) and all-cause and cause-specific mortality.
Methods: We included 96,831 US postmenopausal women aged 50-79 y without known CVD or cancer during baseline enrollment (1993-1998) of the Women's Health Initiative. Dietary information was collected using a validated FFQ. Incident CVD [i.e., ischemic heart disease (IHD) and stroke] and all-cause and cause-specific mortality were ascertained and adjudicated through February 2018.
Results: A total of 9808 incident CVD cases and 19,508 all-cause deaths occurred during a median follow-up of 17.8 y and 18.9 y, respectively. After multivariable adjustment for traditional risk factors and key dietary nutrients including dietary saturated fat, there were modest associations of dietary cholesterol intake with incident CVD (HRQ5versusQ1: 1.12; 95%
Ci: 1.03, 1.21; P-trend < 0.001) and all-cause mortality (HRQ5versusQ1: 1.09; 95%
Ci: 1.02, 1.15; P-trend < 0.001). Significant positive associations were also observed between dietary cholesterol and incident IHD (P-trend = 0.007), incident ischemic stroke (P-trend = 0.002), and CVD mortality (P-trend = 0.002), whereas there was an inverse association for incident hemorrhagic stroke (P-trend = 0.037) and no association for mortality from cancer, Alzheimer disease/dementia, respiratory diseases, or other causes (P-trend > 0.05). Higher egg consumption was also associated with modestly higher risk of incident CVD (P-trend = 0.004) and all-cause mortality (P-trend < 0.001), with HRs of 1.14 (95%
Ci: 1.04, 1.25) and 1.14 (95%
Ci: 1.07, 1.22), respectively, when comparing ≥1 egg/d with <1 egg/wk.
Conclusions: Both higher dietary cholesterol intake and higher egg consumption appeared to be associated with modestly elevated risk of incident CVD and all-cause mortality in US postmenopausal women.
Dehghan M, Mente A, Rangarajan S, et al.
The American Journal of Clinical Nutrition. 2020;111(4):795-803. doi:10.1093/ajcn/nqz348.
Background: Eggs are a rich source of essential nutrients, but they are also a source of dietary cholesterol. Therefore, some guidelines recommend limiting egg consumption. However, there is contradictory evidence on the impact of eggs on diseases, largely based on studies conducted in high-income countries.
Objectives: Our aim was to assess the association of egg consumption with blood lipids, cardiovascular disease (CVD), and mortality in large global studies involving populations from low-, middle-, and high-income countries.
Methods: We studied 146,011 individuals from 21 countries in the Prospective Urban Rural Epidemiology (PURE) study. Egg consumption was recorded using country-specific validated FFQs. We also studied 31,544 patients with vascular disease in 2 multinational prospective studies: ONTARGET (Ongoing Telmisartan Alone and in Combination with Ramipril Global End Point Trial) and TRANSCEND (Telmisartan Randomized Assessment Study in ACEI Intolerant Subjects with Cardiovascular Disease). We calculated HRs using multivariable Cox frailty models with random intercepts to account for clustering by study center separately within each study.
Results: In the PURE study, we recorded 14,700 composite events (8932 deaths and 8477 CVD events). In the PURE study, after excluding those with history of CVD, higher intake of egg (≥7 egg/wk compared with <1 egg/wk intake) was not significantly associated with blood lipids, composite outcome (
Hr: 0.96; 95%
Ci: 0.89, 1.04; P-trend = 0.74), total mortality (
Hr: 1.04; 95%
Ci: 0.94, 1.15; P-trend = 0.38), or major CVD (
Hr: 0.92; 95%
Ci: 0.83, 1.01; P-trend = 0.20). Similar results were observed in ONTARGET/TRANSCEND studies for composite outcome (HR 0.97; 95%
Ci: 0.76, 1.25; P-trend = 0.09), total mortality (
Hr: 0.88; 95%
Ci: 0.62, 1.24; P-trend = 0.55), and major CVD (
Hr: 0.97; 95%
Ci: 0.73, 1.29; P-trend = 0.12).
Conclusions: In 3 large international prospective studies including ∼177,000 individuals, 12,701 deaths, and 13,658 CVD events from 50 countries in 6 continents, we did not find significant associations between egg intake and blood lipids, mortality, or major CVD events. The ONTARGET and TRANSCEND trials were registered at clinicaltrials.gov as NCT00153101. The PURE trial was registered at clinicaltrials.gov as NCT03225586.
Formisano E, Lopes Neri LC, Caffa I, et al.
Nutrition, Metabolism, and Cardiovascular Diseases : NMCD. 2025;35(5):103849. doi:10.1016/j.numecd.2025.103849.
Aims: To evaluate the effect of egg consumption on health outcomes.
Data Synthesis: A systematic search in PubMed, Scopus, Lilacs, and Web of Science was developed using terms ("egg consumption" or "egg intake") and ("health" or "chronic diseases" or "diabetes" or "cancer" or "cholesterol" or "dyslipidemia"), and meta-analyses of observational or interventional studies published since January 2020 were included. The studies' quality was evaluated through AMSTAR-2 and NutriGrade, and the strength of evidence according to sample size, heterogeneity, and quality of articles. Fourteen meta-analyses were included (10 observational, 4 interventional studies). The wide range of outcomes, with substantial variability and high heterogeneity, indicated a lack of robust evidence. The overall quality of studies was critically low. The level of evidence was very weak for all the significant associations: risk of heart failure (RR 1.15; 95%
Ci: 1.02-1.30), cancer mortality (RR 1.13; 95%CI 1.06-1.20), higher levels of LDL cholesterol (WMD 7.39; 95%CI 5.82-8.95), total cholesterol (WMD 9.12; 95%CI 7.35-10.89), and apolipoprotein B-100 (WMD 0.06; 95%CI 0.03-0.08). Conversely, egg intake has been weakly associated with improvements in HDL cholesterol (WMD 1.37; 95%CI 0.49-2.25), apolipoprotein A1 (WMD 0.03; 95%CI 0.01-0.05), and growth parameters in children (WMD 0.47; 95%CI 0.13-0.80). No evidence of association was found among all cardiovascular outcomes and all-cause mortality risk between high vs. low egg consumption.
Conclusion: Due to the critically low strength of studies, insufficient evidence is available to discourage egg consumption, suggesting eggs can be part of a healthy diet.
Mah E, Chen CO, Liska DJ.
Public Health Nutrition. 2020;23(5):935-955. doi:10.1017/S1368980019002441.
Objective: This umbrella review provides an overview of the consistency and gaps in the evidence base on eggs and cardiometabolic health.
Design: PubMed, Web of Science, Cochrane Library, the Nutrition Evidence Systematic Review and Agency for Healthcare Research and Quality databases were screened for evidence-based reviews in English that assessed human studies on egg consumption and cardiometabolic outcomes.
Results: Seven systematic reviews and fifteen meta-analyses were identified, with eighteen of these published since 2015. Overall, the systematic reviews were of low quality, while meta-analyses were of moderate- to high-quality. No association of increased egg intake and risks of heart disease or stroke in the general population were found in the meta-analyses. Increased risk of heart failure was noted in two meta-analyses that analysed the same three cohort studies. Five recent meta-analyses reported no increased risk of type 2 diabetes mellitus (T2DM) in the general population, although increased risk in US-based populations only has been reported. Older (<2013) meta-analyses reported increased risks of cardiovascular disease (CVD) or heart disease in T2DM populations, and no recent evidence-based reviews were identified. Finally, only one meta-analysis reported intervention studies specifically on eggs and biomarkers (i.e. lipids), and the results contradicted those from observation studies.
Conclusions: Recent evidence-based reviews conclude that increased egg consumption is not associated with CVD risk in the general population. More research is needed on the positive associations between egg consumption and heart failure and T2DM risk, as well as CVD risk in diabetics, before firm conclusions can be made.
Marventano S, Godos J, Tieri M, et al.
International Journal of Food Sciences and Nutrition. 2020;71(3):325-331. doi:10.1080/09637486.2019.1648388.
Egg consumption has been an area of controversy regarding its impact on human health largely due to the content in cholesterol and its potential role in cardio-metabolic outcomes. This study aimed to summarise the level of evidence of egg consumption on various health outcomes. A systematic search for meta-analyses was performed: study design, dose-response relationship, heterogeneity and agreement of results over time, and identification of potential confounding factors were considered to assess the level of evidence. Results from this umbrella review showed a substantial no association between egg consumption and a number of health outcomes, including cancer, cardiovascular and metabolic disorders. In contrast, evidence of possible beneficial effects toward stroke risk has been found. In conclusions, egg may be part of a healthy diet; however, additional studies exploring confounding factors are needed to ascertain the potential detrimental effects.