Longitudinal association between egg consumption and the risk of cardiovascular disease: interaction with type 2 diabetes mellitus

Substitution of animal-based with plant-based foods on cardiometabolic health and all-cause mortality: a systematic review and meta-analysis of prospective studies

BACKGROUND

There is growing evidence that substituting animal-based with plant-based foods is associated with a lower risk of cardiovascular diseases (CVD), type 2 diabetes (T2D), and all-cause mortality. Our aim was to summarize and evaluate the evidence for the substitution of any animal-based foods with plant-based foods on cardiometabolic health and all-cause mortality in a systematic review and meta-analysis.

METHODS

We systematically searched MEDLINE, Embase, and Web of Science to March 2023 for prospective studies investigating the substitution of animal-based with plant-based foods on CVD, T2D, and all-cause mortality. We calculated summary hazard ratios (SHRs) and 95% confidence intervals (95% CI) using random-effects meta-analyses. We assessed the certainty of evidence (CoE) using the GRADE approach.

RESULTS

In total, 37 publications based on 24 cohorts were included. There was moderate CoE for a lower risk of CVD when substituting processed meat with nuts [SHR (95% CI): 0.73 (0.59, 0.91), n = 8 cohorts], legumes [0.77 (0.68, 0.87), n = 8], and whole grains [0.64 (0.54, 0.75), n = 7], as well as eggs with nuts [0.83 (0.78, 0.89), n = 8] and butter with olive oil [0.96 (0.95, 0.98), n = 3]. Furthermore, we found moderate CoE for an inverse association with T2D incidence when substituting red meat with whole grains/cereals [0.90 (0.84, 0.96), n = 6] and red meat or processed meat with nuts [0.92 (0.90, 0.94), n = 6 or 0.78 (0.69, 0.88), n = 6], as well as for replacing poultry with whole grains [0.87 (0.83, 0.90), n = 2] and eggs with nuts or whole grains [0.82 (0.79, 0.86), n = 2 or 0.79 (0.76, 0.83), n = 2]. Moreover, replacing red meat for nuts [0.93 (0.91, 0.95), n = 9] and whole grains [0.96 (0.95, 0.98), n = 3], processed meat with nuts [0.79 (0.71, 0.88), n = 9] and legumes [0.91 (0.85, 0.98), n = 9], dairy with nuts [0.94 (0.91, 0.97), n = 3], and eggs with nuts [0.85 (0.82, 0.89), n = 8] and legumes [0.90 (0.89, 0.91), n = 7] was associated with a reduced risk of all-cause mortality.

CONCLUSIONS

Our findings indicate that a shift from animal-based (e.g., red and processed meat, eggs, dairy, poultry, butter) to plant-based (e.g., nuts, legumes, whole grains, olive oil) foods is beneficially associated with cardiometabolic health and all-cause mortality.

Longitudinal association of egg intake frequency with cardiovascular disease in Chinese adults

BACKGROUND AND AIMS

Reducing dietary cholesterol is generally acceptable for the prevention of cardiovascular disease (CVD). Eggs are nutrient-dense and common food items across the world, while rich in cholesterol. The potential effects of egg intake on cardiovascular health remain uncertainty and have been under debate in past decades.

METHODS AND RESULTS

A nationwide cohort of 20,688 participants aged 16-110 years without CVD at baseline were derived from the China Family Panel Studies. Egg consumption was assessed by a semi-quantitative food frequency questionnaire. We adopted stratified Cox proportional hazards model with random intercepts for provinces to evaluate associations of egg intake with CVD incidence. During a median follow-up of 6.0 years, we identified 2395 total CVD incidence and mean egg consumption was 3 times/week. Egg intakes were associated lower risks of CVD incidence in the multivariate-adjusted model. Compared with the non-consumers, the corresponding HRs (95% confidence interval) for total CVD events were 0.84 (0.74-0.94) for 1-2 times per week, 0.78 (0.69-0.88) for 3-6/week, and 0.83 (0.72-0.95) for ≥7/week. Similar relationships were found in hypertension. Approximately non-linear relationships were observed between egg consumption with total CVD and hypertension incidence, identifying the lowest risk in 3-6 times/week. Subgroup analyses estimated lower risks of total CVD and hypertension in females only, with significant effect modification by sex (P for interaction = 0.008 and 0.020).

CONCLUSION

Egg consumption may be associated with lower risks of CVD incidence among Chinese adults. Our findings could have implications in CVD prevention and might be considered in the development of dietary guidelines.

Egg and Dietary Cholesterol Consumption and the Prevalence of Metabolic Syndrome: Findings from a Population-Based Nationwide Cohort

BACKGROUND

Although the Chinese Dietary Guidelines (2016) removed restrictions on dietary cholesterol intake, evidence of egg and dietary cholesterol intake and cardiometabolic diseases is inconsistent. Associations between egg and cholesterol consumption and metabolic syndrome (MetS) in non-Western populations are still poorly documented.

OBJECTIVE

Our aim was to assess egg and dietary cholesterol intake in relation to the prevalence of MetS among participants in a Chinese nationwide study.

DESIGN

This cross-sectional study used data from the China Health and Nutrition Survey (1991-2009).

PARTICIPANTS/SETTING

The sample consisted of 8,241 healthy Chinese adults (20 years and older).

MAIN OUTCOME MEASURES

MetS cases were defined according to the National Cholesterol Education Program Adult Treatment Panel III criteria.

STATISTICAL ANALYSIS

Cumulative means of egg and cholesterol consumption were calculated in accordance with 3 consecutive 24-hour dietary recalls in each examination cycle. Logistic regression models were conducted to assess the associations with prevalent MetS.

RESULTS

Overall, 2,580 (31.3%) participants were identified as MetS cases in 2009. After multivariate adjustment, total egg consumption (>1 egg/d) was associated with 20% higher odds of MetS (odds ratio [OR] 1.20, 95% CI 1.06 to 1.37; P trend = .001) compared with consumption of ≤1/2 egg/d. Examining cooking methods, a positive association was observed between fried egg consumption and MetS odds (OR comparing the highest category [>1/2 egg/d] with the lowest category [≤1/7 egg/d] 1.22, 95% CI 1.08 to 1.39; P trend = .001), and nonfried egg intake was not associated with MetS odds (P trend = .08). Total dietary intake and egg-sourced cholesterol intake were both positively correlated with MetS odds (OR 1.31, 95% CI 1.12 to 1.53; P trend = .005) comparing the highest consumption (>371 mg · 2,000 kcal^-1 · d^-1) with the lowest consumption (≤132 mg · 2,000 kcal^-1 · d^-1) for total dietary cholesterol (OR 1.36; 95% CI 1.17 to 1.58; P trend < .001) and comparing the highest consumption (>232 mg · 2,000 kcal^-1 · d^-1) with the lowest consumption (≤46 mg · 2,000 kcal^-1 · d^-1) for egg-sourced cholesterol; similar associations were not observed for non-egg-sourced cholesterol consumption (P trend = .83). Substituting eggs and fried eggs for other protein sources, including low-fat and whole-fat dairy products; nuts and legumes; total red meat; processed meat; poultry meat; or seafood, was still associated with higher odds of MetS.

CONCLUSIONS

Consumption of >1 egg/d and >1/2 fried egg/d was associated with a higher prevalence of MetS than consumption of ≤1/2 egg/d and ≤1/7 fried egg/d. Future longitudinal cohort studies and randomized controlled trials are needed to further investigate the relationship between egg consumption and MetS and explore possible mechanisms of action.

Egg consumption associated with all-cause mortality in rural China: a 14-year follow-up study

BACKGROUND

Dietary recommendations regarding egg intake remain controversial topic for public health. We hypothesized that there was a positive association between egg consumption and all-cause mortality.

METHODS

To test this hypothesis, we enrolled 9885 adults from a community-based cohort in Anhui Province, China during 2003-05. Egg consumption was assessed by food questionnaire. Stratified analyses were performed for age, sex, body mass index (BMI), blood pressure, smoking, drinking and laboratory tests.

RESULTS

After an average follow-up of 14.1 years, 9444 participants were included for analysis. A total of 814 deaths were recorded. Participants' BMI and lipid profile had no significantly difference between three egg consumption groups. BMI was 21.6±2.7 of the whole population, especially BMI>24 was only 17.3%. A bivariate association of egg consumption >6/week with increased all-cause mortality was observed compared with ≤6/week (RR: 1.35, 95% CI: 1.05, 1.73, P = 0.018). A significant interaction was observed for BMI ≥ 21.2 kg/m2 vs. BMI<21.2 kg/m2 (P for interaction: 0.001). No other significant interactions were found.

CONCLUSIONS

In this study, consuming >6 eggs/week increased risk of all-cause mortality, even among lean participants, especially who with BMI ≥ 21.2 kg/m2. Eggs are an easily accessible and constitute an affordable food source in underdeveloped regions. Consuming <6 eggs/week may be the most suitable intake mode.

Effect of consumption of whole egg and egg fractions on cardiovascular disease factors in adult rats

BACKGROUND

While eggs are a low-cost source of protein, rich in macro- and micronutrients, the association of egg intake and cardiovascular disease (CVD) remains controversial. This study investigated the effect of egg consumption on CVD parameters. Eggs were boiled, separated into four fractions (whole egg, 50% yolk-reduced whole egg, egg yolk and egg white) and then freeze-dried. The different egg fractions or distilled water (control) were orally gavaged to adult male Wistar rats at 1 g kg^-1 rat body weight, each day for 8 weeks, following which basal blood pressure, heart rate, complete blood cell count, blood biochemistry, body fat and liver cell lipid accumulation were determined. The vascular functions of isolated thoracic aorta were studied using classical pharmacological techniques.

RESULTS

In comparison to the control group, none of the egg fractions affected body weight, food intake, plasma glucose or lipid profile. The yolk group experienced increased plasma alkaline phosphatase and creatinine levels, while egg white caused decreased plasma cholesterol and blood urea nitrogen. Whole egg and egg yolk increased blood pressure and mean hemoglobin concentration and the yolk increased liver lipid accumulation. Egg white decreased the white blood cell count and body fat lipids. No changes were found in basal heart rate or vascular functions in any of the groups.

CONCLUSIONS

Consumption of whole egg or egg yolk at the dosage given caused hypertension, with impairment of liver and kidney functions following the intake of yolk alone. However, egg white is beneficial for the cardiovascular system as it decreased plasma cholesterol and body fat accumulation. © 2020 Society of Chemical Industry.

Nutritional Viewpoints on Eggs and Cholesterol

Although most current epidemiologic studies indicate no significant association between consuming one egg daily and blood cholesterol levels and cardiovascular risk, arguments still persist with a positive association. Since the diet is one of the most influential factors for this association, we illustrate characteristic features in Japanese people whose dietary pattern is distinct from that, for example, the US (United States) population. Available epidemiologic studies in healthy Japanese people show no association between consumption of one egg daily and blood cholesterol level, consistent with those observed in the US population. However, when consumption of major nutrients and food sources of cholesterol are compared to the US population, Japanese people may have an extra-reserve against the influence of eggs on cardiovascular risk markers, despite consuming relatively more eggs. Further discussion on the influence of nutrients contained in the egg and dietary pattern, including interaction with gut microbes, is necessary. In addition, special consideration at the personalized level is needed for judgment regarding dietary cholesterol not only for hypercholesterolemic patients but for hyper-responsive healthy persons. Although randomized controlled trials with long-term follow-up are required to evaluate the association between consumption of eggs and human health, available information, at least from the nutritional viewpoint, suggests that egg is a healthy and cost-efficient food worldwide.

Association Between Egg Consumption and Risk of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis

INTRODUCTION

Considerable controversy remains on the relationship between egg consumption and cardiovascular disease risk. The objective of this systematic review and meta-analysis was to explore the association between egg consumption and overall cardiovascular disease events.

METHODS

We systematically searched Ovid MEDLINE, Ovid Embase, Ovid Cochrane Database of Systematic Reviews, Scopus, and Web of Science from database inception in 1966 through January 2020 for observational studies that reported the association between egg consumption and cardiovascular disease events. Two investigators independently reviewed data. Conflicts were resolved through consensus. Random-effects meta-analyses were used. Sources of heterogeneity were analyzed.

RESULTS

We identified 23 prospective studies with a median follow-up of 12.28 years. A total of 1,415,839 individuals with a total of 123,660 cases and 157,324 cardiovascular disease events were included. Compared with the consumption of no or 1 egg/day, higher egg consumption (more than 1 egg/day) was not associated with significantly increased risk of overall cardiovascular disease events (pooled hazard ratios, 0.99; 95% confidence interval, 0.93-1.06; P < .001; I² = 72.1%). Higher egg consumption (more than 1 egg/day) was associated with a significantly decreased risk of coronary artery disease (pooled hazard ratios, 0.89; 95% confidence interval, 0.86-0.93; P < .001; I² = 0%), compared with consumption of no or 1 egg/day.

CONCLUSIONS

Our analysis suggests that higher consumption of eggs (more than 1 egg/day) was not associated with increased risk of cardiovascular disease, but was associated with a significant reduction in risk of coronary artery disease.

The Debate Over Egg Consumption and Incident Cardiovascular Disease

There is a great debate regarding the association of cholesterol intake from egg consumption and the incidence of cardiovascular disease (CVD). Most studies show that moderate egg consumption is not associated with a significant increase in CVD, stroke, heart failure, and type 2 diabetes mellitus (T2DM), whereas others dispute this fact and state that there is an association with increased egg consumption, especially if they are consumed with saturated fats. In addition, the recent relaxation of cholesterol intake to greater than 300 mg/d by the American College of Cardiology/American Heart Association Nutritional Guidelines has fueled this debate. In order to get a current perspective on the significance of moderate egg consumption with the primary incidence of CVD, a focused Medline search of the English language literature was conducted between 2010 and March 2020 using the terms, cholesterol intake, egg consumption, coronary artery disease, CVD, and T2DM. Nineteen pertinent articles were retrieved, and these, together with collateral literature, will be discussed in this review article. The analysis of data from the articles retrieved indicated that several studies showed that moderate egg consumption (1 egg/d) is not associated with adverse cardiovascular effects in subjects free of CVD or T2DM, whereas other studies showed a positive association, especially in patients with preexisting CVD or T2DM. Therefore, at present, there is no unanimous agreement on this subject, and the controversy will continue until new confirmatory evidence becomes available.

Egg consumption and cardiovascular risk: a dose-response meta-analysis of prospective cohort studies

Purpose

Cardiovascular disease (CVD) is a leading cause of mortality globally and is strongly influenced by dietary risk factors. The aim was to assess the association between egg consumption and risk of CVD risk/mortality, including coronary heart disease (CHD), stroke, and heart failure.

Methods

MEDLINE, Embase, and Web of Science databases were searched through April 2020 for prospective studies. Two independent reviewers screened and extracted the data through standardized methods. Size effects were calculated as summary relative risks (SRRs) in a dose–response fashion through random-effects meta-analyses.

Results

Thirty-nine studies including nearly 2 million individuals and 85,053 CHD, 25,103 stroke, 7536 heart failure, and 147,124 CVD cases were included. The summary analysis including 17 datasets from 14 studies conducted on CVD (incidence and/or mortality) showed that intake of up to six eggs per week is inversely associated with CVD events, when compared to no consumption [for four eggs per week, SRR = 0.95 (95% CI: 0.90; 1.00)]; a decreased risk of CVD incidence was observed for consumption of up to one egg per day [SRR = 0.94 (95% CI: 0.89; 0.99)]. The summary analysis for CHD incidence/mortality including 24 datasets from 16 studies showed a decreased risk up to two eggs per week [(SRR = 0.96 (95% CI: 0.91; 1.00)]. No associations were retrieved with risk of stroke. The summary analysis for heart failure risk including six datasets from four studies showed that intake of one egg per day was associated with increased risk raising for higher intakes compared to no consumption [for 1 egg per day, SRR = 1.15 (95% CI:1.02; 1.30)]. After considering GRADE criteria for strength of the evidence, it was rated low for all outcomes but stroke, for which it was moderate (yet referring to no risk).

Conclusion

There is no conclusive evidence on the role of egg in CVD risk, despite the fact that higher quality studies are warranted to obtain stronger evidence for a possible protection of CVD associated with moderate weekly egg consumption compared to no intake; equally, future studies may strengthen the evidence for increased heart failure risk associated with high regular egg consumption.

Electronic supplementary material

The online version of this article (10.1007/s00394-020-02345-7) contains supplementary material, which is available to authorized users.

Egg consumption and risk of cardiovascular disease: three large prospective US cohort studies, systematic review, and updated meta-analysis

OBJECTIVE

To evaluate the association between egg intake and cardiovascular disease risk among women and men in the United States, and to conduct a meta-analysis of prospective cohort studies.

DESIGN

Prospective cohort study, and a systematic review and meta-analysis of prospective cohort studies.

SETTING

Nurses' Health Study (NHS, 1980-2012), NHS II (1991-2013), Health Professionals' Follow-Up Study (HPFS, 1986-2012).

PARTICIPANTS

Cohort analyses included 83 349 women from NHS, 90 214 women from NHS II, and 42 055 men from HPFS who were free of cardiovascular disease, type 2 diabetes, and cancer at baseline.

MAIN OUTCOME MEASURES

Incident cardiovascular disease, which included non-fatal myocardial infarction, fatal coronary heart disease, and stroke.

RESULTS

Over up to 32 years of follow-up (>5.54 million person years), 14 806 participants with incident cardiovascular disease were identified in the three cohorts. Participants with a higher egg intake had a higher body mass index, were less likely to be treated with statins, and consumed more red meats. Most people consumed between one and less than five eggs per week. In the pooled multivariable analysis, consumption of at least one egg per day was not associated with incident cardiovascular disease risk after adjustment for updated lifestyle and dietary factors associated with egg intake (hazard ratio for at least one egg per day v less than one egg per month 0.93, 95% confidence interval 0.82 to 1.05). In the updated meta-analysis of prospective cohort studies (33 risk estimates, 1 720 108 participants, 139 195 cardiovascular disease events), an increase of one egg per day was not associated with cardiovascular disease risk (pooled relative risk 0.98, 95% confidence interval 0.93 to 1.03, I²=62.3%). Results were similar for coronary heart disease (21 risk estimates, 1 411 261 participants, 59 713 coronary heart disease events; 0.96, 0.91 to 1.03, I²=38.2%), and stroke (22 risk estimates, 1 059 315 participants, 53 617 stroke events; 0.99, 0.91 to 1.07, I²=71.5%). In analyses stratified by geographical location (P for interaction=0.07), no association was found between egg consumption and cardiovascular disease risk among US cohorts (1.01, 0.96 to 1.06, I²=30.8%) or European cohorts (1.05, 0.92 to 1.19, I²=64.7%), but an inverse association was seen in Asian cohorts (0.92, 0.85 to 0.99, I²=44.8%).

CONCLUSIONS

Results from the three cohorts and from the updated meta-analysis show that moderate egg consumption (up to one egg per day) is not associated with cardiovascular disease risk overall, and is associated with potentially lower cardiovascular disease risk in Asian populations.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42019129650.

Associations of Dietary Intake with Cardiovascular Disease, Blood Pressure, and Lipid Profile in the Korean Population: a Systematic Review and Meta-Analysis

OBJECTIVE

Previous studies have separately reported the contributions of dietary factors to the risk of cardiovascular disease (CVD) and its markers, including blood pressure (BP) and lipid profile. This study systematically reviewed the current evidence on this issue in the Korean population.

METHODS

Sixty-two studies from PubMed and Embase were included in this meta-analysis. We performed a random-effects model to analyze pooled odds ratios (ORs) and hazard ratios (HRs) and their 95% confidence intervals (CIs) for the consumption of 14 food items, three macro- and eight micro-nutrients, two dietary patterns, and three dietary indices.

RESULTS

An analysis of pooled effect sizes from at least four individual study populations showed significant associations between coffee consumption and CVD (OR/HR, 0.71; 95% CI, 0.52-0.97) and elevated/high triglycerides (TG) (OR, 0.84; 95% CI, 0.78-0.90), sugar-sweetened beverage intake and elevated BP (OR/HR, 1.20; 95% CI, 1.09-1.33), and milk and dairy intake and elevated/high TG and low high-density lipoprotein cholesterol (HDL-C) (OR/HR, 0.82; 95% CI, 0.76-0.89 for both). Carbohydrate consumption and the low-carbohydrate-diet score were consistently related to an approximately 25% risk reduction for elevated TG and low HDL-C. A lower risk of elevated total cholesterol, but not low-density lipoprotein, was additionally observed for those with a higher low-carbohydrate-diet score. A healthy dietary pattern was only associated with a reduced risk of elevated TG in the Korea National Cancer Screenee Cohort (OR, 0.81; 95% CI, 0.67-0.98).

CONCLUSION

This study showed that milk and dairy and coffee had protective effects for CVD and its risk factors, such as BP and lipid profile, while sugar-sweetened beverages exerted harmful effects.

[SEA/SEMERGEN consensus document 2019: Dietary recommendations in the prevention of cardiovascular disease]

The current paradigm in the nutrition sciences states that the basic nutritional unit is not the nutrients, but the foods that contain them (oils, nuts, dairy products, eggs, red or processed meats, etc.). These act as a food matrix in which the different nutrients synergistically or antagonistically modulate their effects on the various metabolic pathways determining health and disease. Food is not based on nutrients or isolated foods but on complex mixtures of one and the other that are part of a specific food pattern, a concept that has been targeted as the most pertinent to evaluate the associations between nutrition and health or disease. This document presents a summary of the available evidence on the relationship between different foods and cardiovascular health, and offers simple recommendations to be implemented in the dietary advice offered by the health professional.

Association between Dietary Cholesterol and Their Food Sources and Risk for Hypercholesterolemia: The 2012⁻2016 Korea National Health and Nutrition Examination Survey

It remains unclear whether cholesterol intake can increase serum cholesterol. Therefore, the present study aimed to investigate the hypothesis that the risk for hypercholesterolemia was not associated with intake of dietary cholesterol after adjusting for saturated fatty acid (SFA). Based on the data from the 2012–2016 KNHANES, dietary cholesterol was positively associated with the risk for abnormalities in total cholesterol (TC) (odds ratio (OR): 1.153, 95% confidence interval (CI): 0.995–1.337; p = 0.028) and low-density lipoprotein cholesterol (LDL-C) (OR: 1.186, 95% CI: 1.019–1.382; p = 0.018) levels before adjusting for SFA; after adjusting for SFA, no significant associations were found between these variables. The mediation analysis showed that dietary cholesterol had no direct effects on the serum levels of TC and LDL-C; in contrast, SFA had significant indirect effects on the association between dietary cholesterol and serum levels of TC and LDL-C. Furthermore, processed meats, but not eggs and other meats, were positively associated with the risk for abnormalities in both TC (OR: 1.220, 95% CI: 1.083–1.374; p = 0.001) and LDL-C (OR: 1.193, 95% CI: 1.052–1.354; p = 0.004) levels. The present study suggested that higher intake of processed meats with high SFA, but not dietary cholesterol was associated with higher risk for abnormalities in TC and LDL-C levels.

SEA/SEMERGEN consensus document 2019: Dietary recommendations in the prevention of cardiovascular disease

The current paradigm in the nutrition sciences states that the basic nutritional unit is not the nutrients, but the foods that contain them (oils, nuts, dairy products, eggs, red or processed meats, etc.). These act as a food matrix in which the different nutrients synergistically or antagonistically modulate their effects on the various metabolic pathways determining health and disease. Food is not based on nutrients or isolated foods but on complex mixtures of one and the other that are part of a specific food pattern, a concept that has been targeted as the most pertinent to evaluate the associations between nutrition and health or disease. This document presents a summary of the available evidence on the relationship between different foods and cardiovascular health, and offers simple recommendations to be implemented in the dietary advice offered by the health professional.