Egg consumption and risk of type 2 diabetes: a prospective study and dose-response meta-analysis

A diet-wide Mendelian randomization analysis: causal effects of dietary habits on type 2 diabetes

Background

Traditional clinical studies have indicated a link between certain food intakes and type 2 diabetes (T2D), but the causal relationships between different dietary habits and T2D remain unknown. Using Mendelian randomization (MR) approaches, we investigated the potential causal association between dietary habits and T2D risk.

Methods

We collected publicly available genome-wide association studies' summary statistics for 18 dietary habits from the UK Biobank and T2D data from the DIAbetes Genetics Replication And Meta-analysis (DIAGRAM) consortium. We applied the inverse variance weighted (IVW) method, supplemented with the MR-Egger method, weighted median method (WMM), simple method, weighted mode, MR-Egger regression, and the MR pleiotropy residual sum and outlier test to determine whether a particular diet was causal for T2D.

Results

Reliable and robust MR estimates demonstrated that poultry intake has a causal effect on a higher risk of T2D (IVW: OR 6.30, 95% CI 3.573-11.11, p = 2.02e - 10; WMM: OR 5.479, 95% CI 0.2758-10.88, p = 1.19e - 06). Conversely, dried fruit intake (IVW: OR 0.380, 95% CI 0.237-0.608, p = 5.57e - 05; WMM: OR 0.450, 95% CI 0.321-0.630, p = 3.33e - 06) and cereal intake (IVW: OR 0.455, 95% CI 0.317-0.653, p = 1.924e - 05; WMM: OR 0.513, 95% CI 0.379-0.694, p = 1.514e - 05) were causally associated with T2D as protective factors. Sensitivity analyses confirmed the reliability and robustness of these findings.

Discussion

Our study established the causal effects of poultry intake, dried fruit intake, and cereal intake on T2D, identifying poultry intake as a risk factor and the other two as protective factors. Further research into potential mechanisms is required to validate these novel findings.

Eggs - a scoping review for Nordic Nutrition Recommendations 2023

Cardiovascular diseases (CVD), type 2 diabetes (T2D), and cancer are a significant public health burden in the Nordic and Baltic countries. High intake of eggs, mainly due to its high cholesterol content, has been suggested to have adverse health effects. The purpose of this scoping review is to describe the evidence related to the impact of egg intake on health. A literature search identified 38 systematic reviews and meta-analyses on egg consumption in relation to health outcomes published between 2011 and 30 April 2022. Overall, current evidence from systematic reviews of randomized clinical trials indicates that higher egg intake may increase serum total cholesterol concentration and the ratio of low-density lipoprotein to high-density lipoprotein cholesterol, but with substantial heterogeneity in the response. However, recent evidence from observational studies does not provide strong support for a detrimental role of moderate egg consumption (up to one egg/day) on the risk of CVD, especially in the European studies. The overall evidence from observational studies indicates that egg consumption is not associated with increased risk of mortality or T2D in European study populations. There is also little support for a role of egg consumption in cancer development, although a weak association with higher risk of certain cancers has been found in some studies, mainly case-control studies. Again, no associations with cancer risk have been observed in European studies. Systematic reviews and meta-analyses of egg consumption in relation to other health-related outcomes are scarce. There are also limited data available on the associations between the consumption of more than one egg/day and risk of diseases. Based on the available evidence, one egg/day is unlikely to adversely affect overall disease risk.

Effects of Egg Consumption on Subjects with SLD or Hypertension: A MICOL Study

BACKGROUND

Steatotic liver disease (SLD) is defined as a fat accumulation in more than 5% of hepatocytes; it can progress to non-alcoholic steatohepatitis (NASH), associated with an increased state of inflammation. The aim of this study was to explore the protective effects of eating eggs and any association with SLD and hypertension (HTN).

METHODS

The study cohort included 908 participants assessed in the fourth recall of the MICOL study, grouped into four groups, based on NALFD and/or HTN.

RESULTS

The prevalence of HTN and SLD among participants was 31.61%. Overall, the results indicated a statistical significance of egg consumption, showing a protective role against the two disease conditions, in both the raw and adjusted models (RRR = 0.34, p = 0.009, 0.15 to 0.76 95% C.I.).

CONCLUSIONS

Many differences were found among the groups, and the protective role of eating eggs was amply demonstrated. We can conclude that it is unwise to demonize the intake of this food and its nutritional properties, in contrast with previous reports in the literature.

Egg Consumption in the Context of Plant-Based Diets and Diet Quality in Adults at Risk for Type 2 Diabetes: A Randomized Single Blind Cross-over Controlled Trial

Lifestyle changes that emphasis on plant-based diets (PBD) are typically recommended for those at risk for type 2 diabetes mellitus (T2DM) to mitigate their cardo-metabolic risk. We examined the impact of the inclusion of eggs compared with their exclusion from PBD on diet quality among adults at risk for T2DM.

This was a randomized, controlled, single-blind, crossover trial of 35 adults (mean age 60.7 years; 25 women, 10 men; 34 Caucasians, 1 African-American) at risk for T2DM (i.e., pre- diabetes or metabolic syndrome) assigned to one of two possible sequence permutations of two treatments (PBD with eggs and exclusively PBD), with a 4-week washout period. Participants received dietary counseling from a dietitian to exclude or to include 2 eggs daily in the context of PBD for a 6-week period. Diet quality was assessed using the Healthy Eating Index 2015 (HEI-2015) at baseline and 6 weeks.

Compared with the exclusion of eggs, the inclusion of eggs in the context of PBD improved the diet quality score for intake of total protein foods (1.0 ± 1.1 vs. -0.4 ± 1.0; p <.0001); seafood and plant proteins (0.2 ± 1.2 vs. -0.4 ± 1.1; p = 0.0338); and fatty acids (0.8 ± 2.5 vs. -0.7 ± 2.7; p = 0.0260). Overall diet quality score depreciated with the adoption of exclusively PBD without eggs (-3.1 ± 8.3; p = 0.0411), while it was unaffected with the adoption of a PBD with the inclusion of eggs (-0.6 ± 7.9; p = 0.6892).

Eggs could be used as an adjuvant to enhance the diet quality among those at risk for T2DM who adopt plant-based dietary patterns.

Egg Intake Is Associated with Lower Risks of Impaired Fasting Glucose and High Blood Pressure in Framingham Offspring Study Adults

The association between egg consumption and cardiometabolic risk factors such as high blood pressure (HBP) and impaired fasting glucose (IFG) or type 2 diabetes (T2D) is still under debate. This study examines the association between egg consumption and these outcomes among 2349 30-64 year-old adults in the prospective Framingham Offspring Study. Diet was assessed using three-day dietary records. Potential confounders retained in the final models included age, sex, body mass index, and other dietary factors. The analysis of covariance and Cox proportional hazard's models were used to assess the relevant continuous (i.e., FG, SBP, DBP) and categorical (i.e., T2D, HBP) outcomes. Consuming ≥5 eggs per week was associated with lower mean FG (p = 0.0004) and SBP (p = 0.0284) after four years of follow-up. Higher egg intakes led to lower risks of developing IFG or T2D (HR: 0.72; 95% CI: 0.51-1.03) and high blood pressure (HBP) (HR: 0.68; 0.50-0.93). The beneficial effects of egg consumption were stronger in combination with other healthy dietary patterns. This study found that regular egg consumption as part of a healthy diet had long-term beneficial effects on blood pressure and glucose metabolism and lowered the long-term risks of high blood pressure and diabetes.

The association of egg consumption with blood pressure levels and glycated hemoglobin in Spanish adults according to body mass index

The objective of this study was to evaluate the association of egg consumption with blood pressure (BP) and glycated hemoglobin (HbA1c). In addition, it was assessed whether this association changes according to body weight status. This cross-sectional study is based on multicenter data from Spanish adult participants in the EVIDENT II trial. Egg consumption was assessed with a Food Frequency Questionnaire, and data on BP and HbA1c were collected using standardized procedures. Linear regression and ANCOVA models adjusted for the main confounders were performed. The analyses were stratified by body weight status. A total of 668 participants were analyzed (mean age 52.4 ± 11.8 years, 62.3% women). Compared with lower consumption, higher egg consumption was associated with lower systolic (ß =  - 6.15 ± 1.74; p-for-trend = 0.017), diastolic (ß =  - 4.41 ± 1.03; p-for-trend = 0.002), and mean arterial pressure (ß =  - 4.99 ± 1.17; p-for-trend = 0.003) and with lower HbA1c (ß =  - 0.19 ± 0.06; p-for-trend = 0.019) levels. These associations lost statistical significance in the adjusted analyses. The results did not vary by body weight status. In conclusion, consumption of up to 1 egg per day is not associated with BP or HbA1c, even in overweight or obese individuals. Our findings suggested that this frequency of egg consumption is safe as part of a healthy diet and lifestyle for cardiometabolic risk.

Replacing Red Meat with Other Nonmeat Food Sources of Protein is Associated with a Reduced Risk of Type 2 Diabetes in a Danish Cohort of Middle-Aged Adults

BACKGROUND

Few cohort studies have modelled replacements of red meat with other sources of protein on subsequent risk of type 2 diabetes using dietary changes.

OBJECTIVES

To determine whether replacing red meat with other food sources of protein is associated with a lower risk of type 2 diabetes.

METHODS

We used data from the Danish Diet, Cancer, and Health cohort (n = 39,437) of middle-aged (55-72 years old) men and women who underwent 2 dietary assessments roughly 5 years apart to investigate dietary changes. The pseudo-observation method was used to model the average exposure effect of decreasing the intake of red meat while increasing the intake of either poultry, fish, eggs, milk, yogurt, cheese, whole grains, or refined grains on the subsequent 10-year risk of developing type 2 diabetes, compared with no changes in the intakes of these foods.

RESULTS

Replacing 1 serving/day (100 g/day) of red meat with 1 serving/day of eggs [risk difference (RD), -2.7%; 95% CI: -4.0 to -1.1%; serving size: 50 g/day], milk (RD, -1.2%; 95% CI: -2.1 to -0.4%; 200 g/day), yogurt (RD, -1.5%; 95% CI: -2.4 to -0.7%; 70 g/day), whole grains (RD, -1.7%; 95% CI: -2.5 to -0.9%; 30 g/day), or refined grains (RD, -1.2%; 95% CI: -2.0 to -0.3%; 30 g/day) was associated with a reduced risk of type 2 diabetes. Analyses of replacements with poultry or cheese, but not fish, also suggested a lower risk, but with wide CIs. After further adjustment for potential mediators (BMI, waist circumference, and history of hypertension or hypercholesterolemia), only the replacement with eggs was associated with a reduced risk (RD, -1.7%; 95% CI: -3.0 to -0.5%; 50 g/day).

CONCLUSIONS

Replacing red meat with eggs in middle-aged adults may reduce the risk of type 2 diabetes. In models not adjusted for potential mediators, replacing red meat with milk, yogurt, whole grains, or refined grains was also associated with a reduced risk of type 2 diabetes.

Egg, cholesterol and protein intake and incident type 2 diabetes mellitus: Results of repeated measurements from a prospective cohort study

BACKGROUND & AIMS

Epidemiological evidence on the associations of egg, cholesterol and protein intake with risk of type 2 diabetes is inconsistent. Therefore, we conducted this study to explore these associations among Chinese adults.

METHODS

Data from 4 waves (2004, 2006, 2009 and 2011) of the China Health and Nutrition Survey were used. A multistage random-cluster sampling method was employed to recruit the participants in both rural and urban areas. We included individuals who participated in 2004 and any waves afterwards. Those 1) below 18 years of age; 2) with diabetes at baseline; or 3) with extreme energy intake (men: <800 kcal or >6000 kcal; women: <600 kcal or >4000 kcal) were excluded. Respondents were classified into four groups according to quartiles of egg, cholesterol and protein intake per day. Numbers of eggs per day were calculated by dividing egg intake in grams by 50 g. Diagnosis of type 2 diabetes was self-reported. Logistic generalized estimation equation models were employed.

RESULTS

There were 7312 individuals included in 2004, 6390 in 2006, 4826 in 2009 and 4963 in 2011. The mean age of participants at baseline was 48.3 years and 47.2% were men. Over an average of 5.8-y follow-up, 209 developed type 2 diabetes. After adjustment for demographic, lifestyle and dietary confounders, the odds ratio of type 2 diabetes for those in the highest compared with the lowest protein intake quartile was 2.38 (95% CI: 1.43, 3.98). The odds ratio of individuals with ≥3 eggs/day versus none was 3.76 (95% CI, 2.05, 6.90). Cholesterol intake was not associated with type 2 diabetes.

CONCLUSIONS

Individuals with the highest protein intake had over a 2-fold increased risk of type 2 diabetes compared with those with the lowest protein intake. A high intake of egg, but not dietary cholesterol, was associated with type 2 diabetes. This association warrants further investigation.

Interactive associations of the INAFM2 rs67839313 variant and egg consumption with type 2 diabetes mellitus and fasting blood glucose in a Chinese population: A family-based study

BACKGROUND

INAFM2 rs67839313 was associated with type 2 diabetes (T2DM) in Japanese populations but not in other populations. We aimed to validate the association of rs67839313 with T2DM and explore interactive associations of INAFM2 rs67839313 and egg consumption with T2DM and fasting blood glucose (FBG) in a Chinese population.

METHODS

In total, 7175 participants (4202 T2DM cases) from 3980 families were included and categorized into two groups (<4 and ≥4 eggs/week) according to the median egg consumption. Multilevel logistic regression and linear regression models were performed to estimate the genetic associations of rs67839313 with T2DM and FBG, respectively. The crossproduct term between the variant and egg was included in the models for interaction analysis.

RESULTS

We found that rs67839313_T was associated with an increased risk of T2DM (1.22 [95% CI: 1.17-1.27], P < 0.001). Among individuals with the rs67839313_T genotype, those with egg consumption <4/week (1.37 [1.25-1.51]) had a higher T2DM risk than those with egg consumption ≥4/week (1.17 [1.11-1.23]). A significant interactive effect between rs67839313_T and egg consumption on T2DM risk was identified (P = 0.008). Moreover, among participants without T2DM, rs67839313_T was associated with FBG, with a 0.188 mmol/l increase and a 0.152 mmol/l decrease among those consuming <4 eggs/week and ≥4 eggs/week, respectively. The interaction between rs67839313_T and egg consumption was observed to be significantly associated with FBG (P = 0.003).

CONCLUSIONS

INAFM2 rs67839313_T was associated with increased T2DM risk and FBG levels in Chinese individuals, and consuming more eggs may eliminate the associated genetic risk. This finding has important implications for understanding the genetic pathogenesis of T2DM and for the precision nutrition management of T2DM.

Egg consumption and health outcomes: a global evidence mapping based on an overview of systematic reviews

BACKGROUND

Several systematic reviews and meta-analyses have assessed the association between egg consumption and human health, but the evidence is often conflicting.

METHODS

We conducted a systematic literature search to find all systematic reviews and meta-analyses that assess the association between egg consumption and any type of health outcome. We used AMSTAR to evaluate the methodological quality of the reviews, and GRADE to determine the quality of evidence. We visualized the results using a human anatomy diagram and evidence mapping.

RESULTS

Our search revealed 29 systematic reviews and meta-analyses. Eight studies were of high methodological quality, 16 studies of medium quality, and five studies of low quality. We identified 34 primary outcomes from the included 29 reviews, which were combined into a total of 22 different health outcomes. Two of the primary outcomes were based on high-quality evidence, 18 on moderate-quality evidence, and 14 on low-quality evidence. Egg consumption was associated with an increased risk of two diseases and decreased risk of six outcomes. For ten outcomes, no significant association was found, and for four outcomes, different reviews came to conflicting conclusions.

CONCLUSIONS

The association between egg consumption and the risk of cancer, diabetes, cardiovascular diseases and other related diseases has been studied in several meta-analyses. The evidence from different studies on the same topic was often conflicting, which can complicate the making of dietary recommendations.

Replacement of Red and Processed Meat With Other Food Sources of Protein and the Risk of Type 2 Diabetes in European Populations: The EPIC-InterAct Study

OBJECTIVE

There is sparse evidence for the association of suitable food substitutions for red and processed meat on the risk of type 2 diabetes. We modeled the association between replacing red and processed meat with other protein sources and the risk of type 2 diabetes and estimated its population impact.

RESEARCH DESIGN AND METHODS

The European Prospective Investigation into Cancer (EPIC)-InterAct case cohort included 11,741 individuals with type 2 diabetes and a subcohort of 15,450 participants in eight countries. We modeled the replacement of self-reported red and processed meat with poultry, fish, eggs, legumes, cheese, cereals, yogurt, milk, and nuts. Country-specific hazard ratios (HRs) for incident type 2 diabetes were estimated by Prentice-weighted Cox regression and pooled using random-effects meta-analysis.

RESULTS

There was a lower hazard for type 2 diabetes for the modeled replacement of red and processed meat (50 g/day) with cheese (HR 0.90, 95% CI 0.83-0.97) (30 g/day), yogurt (0.90, 0.86-0.95) (70 g/day), nuts (0.90, 0.84-0.96) (10 g/day), or cereals (0.92, 0.88-0.96) (30 g/day) but not for replacements with poultry, fish, eggs, legumes, or milk. If a causal association is assumed, replacing red and processed meat with cheese, yogurt, or nuts could prevent 8.8%, 8.3%, or 7.5%, respectively, of new cases of type 2 diabetes.

CONCLUSIONS

Replacement of red and processed meat with cheese, yogurt, nuts, or cereals was associated with a lower rate of type 2 diabetes. Substituting red and processed meat by other protein sources may contribute to the prevention of incident type 2 diabetes in European populations.

Adverse impact of egg consumption on fatty liver is partially explained by cardiometabolic risk factors: A population-based study

BACKGROUND AND AIMS

We evaluated the association of egg consumption with liver tests (LTs) and non-alcoholic fatty liver disease (NAFLD). This relationship is poorly documented.

METHODS

The National Health and Nutrition Examination Survey (NHANES, 2005-2010) database was used. Analysis of covariance, adjusted linear and logistic regression models were used.

RESULTS

Of the 14,369 participants, 46.8% were men and 45.2% had NAFLD. After correction for several variables including: age, gender, race, education, poverty to income ratio, alcohol intake, energy intake, smoking, and physical activity - fatty liver index (FLI), serum aspartate aminotransferase (AST) alanine aminotransferase (ALT) were 36.9, 25.8 (U/L) and 23.9 (U/L), respectively, in the first tertile (T1) reaching 68.7, 34.9 and 36.5, respectively, in the third tertile (T3) (p < 0.001 for all comparisons). In the model with same covariates, there was significant positive linear relationship between FLI (standard β coefficient (β): 0.196), AST (β: 0.099) and ALT (β: 0.112) with egg consumption and participants in the highest tertile (T3) of egg consumption had 11% higher chance of NAFLD compared with T1 (odds ratio: 1.11 and 95% confidence interval: 1.07-1.17). Of note, after more correction for triglycerides, hypertension and diabetes, the significant link between egg consumption and LTs and/or NAFLD attenuated and disappeared.

CONCLUSION

Our findings highlight the adverse role of egg consumption on LTs and likelihood of NAFLD. These associations seem to be attributable to cardio-metabolic risk factors. These findings require confirmation to improve our understanding of the role of egg consumption in the pathogenesis of NAFLD.

Egg consumption and risk of type 2 diabetes: findings from 3 large US cohort studies of men and women and a systematic review and meta-analysis of prospective cohort studies

BACKGROUND

Whether egg consumption is associated with the risk of type 2 diabetes (T2D) remains unsettled.

OBJECTIVES

We evaluated the association between egg consumption and T2D risk in 3 large US prospective cohorts, and performed a systematic review and meta-analysis of prospective cohort studies.

METHODS

We followed 82,750 women from the Nurses' Health Study (NHS; 1980-2012), 89,636 women from the NHS II (1991-2017), and 41,412 men from the Health Professionals Follow-up Study (HPFS; 1986-2016) who were free of T2D, cardiovascular disease, and cancer at baseline. Egg consumption was assessed every 2-4 y using a validated FFQ. We used Cox proportional hazard models to estimate HRs and 95% CIs.

RESULTS

During a total of 5,529,959 person-years of follow-up, we documented 20,514 incident cases of T2D in the NHS, NHS II, and HPFS. In the pooled multivariable model adjusted for updated BMI, lifestyle, and dietary confounders, a 1-egg/d increase was associated with a 14% (95% CI: 7%, 20%) higher T2D risk. In random-effects meta-analysis of 16 prospective cohort studies (589,559 participants; 41,248 incident T2D cases), for each 1 egg/d, the pooled RR of T2D was 1.07 (95% CI: 0.99, 1.15; I2 = 69.8%). There were, however, significant differences by geographic region (P for interaction = 0.01). Each 1 egg/d was associated with higher T2D risk among US studies (RR: 1.18; 95% CI: 1.10, 1.27; I2 = 51.3%), but not among European (RR: 0.99; 95% CI: 0.85, 1.15; I2 = 73.5%) or Asian (RR: 0.82; 95% CI: 0.62, 1.09; I2 = 59.1%) studies.

CONCLUSIONS

Results from the updated meta-analysis show no overall association between moderate egg consumption and risk of T2D. Whether the heterogeneity of the associations among US, European, and Asian cohorts reflects differences in egg consumption habits warrants further investigation.This systematic review was registered at www.crd.york.ac.uk/prospero as CRD42019127860.

Egg consumption and risk of type 2 diabetes mellitus in middle and elderly Chinese population: An observational study

Data on the association between egg consumption and the risk of type 2 diabetes mellitus (T2DM) in the Chinese population are scarce. In the present study, we aimed to examine the association between egg consumption and the risk of T2DM in a middle and elderly Chinese population. A total of 3298 subjects (1645 men and 1653 women) from the Nutrition and Health Survey (2015-2017) in Hangzhou city were selected for the final analysis. Egg consumption was assessed using a validated food frequency questionnaire. All biochemical data and anthropometric measurements were collected following standardized procedures. Multivariable logistic regression analyses were used to assess the association between egg consumption and the risk of T2DM and the results were presented as odds ratios and 95% confidence interval (CI). Restricted cubic spline combined with logistic regression was used to explore the dose-response relationship between egg consumption and T2DM. Among 3298 subjects, 693 (21.0%) people had T2DM. Compared with participants who did not consume egg per week, the multivariable-adjusted odds ratios were 0.97 (95%CI : 0.78-1.21), 1.08 (95%CI : 0.91-1.06), 1.20 (95%CI : 0.94-1.55), 1.27 (95%CI : 0.99-1.68) in men (P > .05); 1.06 (95%CI : 0.81-1.37), 0.97 (95%CI : 0.78-1.21), 1.26 (95%CI : 0.99-1.59), 1.19 (0.92-1.54) in women (P > .05); 0.89 (95%CI : 0.79-1.04), 0.98 (95%CI : 0.91-1.06), 1.06 (95%CI : 0.87-1.30), 1.09 (95%CI : 0.88-1.34) in both men and women for egg consumption 0∼7, 7, 7∼14, and ≥14 eggs/week, respectively (P > .05). The dose-response curve showed that, with the increase of egg consumption, the risk of T2DM first increased and then decreased (P = .027).We found that the association between egg consumption and T2DM was nonlinear, and higher egg consumption was not associated with an elevated risk for T2DM in middle-aged and elderly Chinese. However, future prospective studies are needed to confirm these findings.

Dietary Protein Consumption and the Risk of Type 2 Diabetes: ADose-Response Meta-Analysis of Prospective Studies

The relationship between dietary protein consumption and the risk of type 2 diabetes (T2D) has been inconsistent. The aim of this meta-analysis was to explore the relations between dietary protein consumption and the risk of T2D. We conducted systematic retrieval of prospective studies in PubMed, Embase, and Web of Science. Summary relative risks were compiled with a fixed effects model or a random effects model, and a restricted cubic spline regression model and generalized least squares analysis were used to evaluate the diet–T2D incidence relationship. T2D risk increased with increasing consumption of total protein and animal protein, red meat, processed meat, milk, and eggs, respectively, while plant protein and yogurt had an inverse relationship. A non-linear association with the risk for T2D was found for the consumption of plant protein, processed meat, milk, yogurt, and soy. This meta-analysis suggests that substitution of plant protein and yogurt for animal protein, especially red meat and processed meat, can reduce the risk for T2D.

Multiple health and environmental impacts of foods

Dietary choices are a leading global cause of mortality and environmental degradation and threaten the attainability of the UN’s Sustainable Development Goals and the Paris Climate Agreement. To inform decision making and to better identify the multifaceted health and environmental impacts of dietary choices, we describe how consuming 15 different food groups is associated with 5 health outcomes and 5 aspects of environmental degradation. We find that foods associated with improved adult health also often have low environmental impacts, indicating that the same dietary transitions that would lower incidences of noncommunicable diseases would also help meet environmental sustainability targets.

Food choices are shifting globally in ways that are negatively affecting both human health and the environment. Here we consider how consuming an additional serving per day of each of 15 foods is associated with 5 health outcomes in adults and 5 aspects of agriculturally driven environmental degradation. We find that while there is substantial variation in the health outcomes of different foods, foods associated with a larger reduction in disease risk for one health outcome are often associated with larger reductions in disease risk for other health outcomes. Likewise, foods with lower impacts on one metric of environmental harm tend to have lower impacts on others. Additionally, of the foods associated with improved health (whole grain cereals, fruits, vegetables, legumes, nuts, olive oil, and fish), all except fish have among the lowest environmental impacts, and fish has markedly lower impacts than red meats and processed meats. Foods associated with the largest negative environmental impacts—unprocessed and processed red meat—are consistently associated with the largest increases in disease risk. Thus, dietary transitions toward greater consumption of healthier foods would generally improve environmental sustainability, although processed foods high in sugars harm health but can have relatively low environmental impacts. These findings could help consumers, policy makers, and food companies to better understand the multiple health and environmental implications of food choices.

The effect of egg consumption on cardiometabolic health outcomes: an umbrella review

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.

Egg consumption and human health: an umbrella review of observational studies

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.

Role of diet in type 2 diabetes incidence: umbrella review of meta-analyses of prospective observational studies

OBJECTIVE

To summarise the evidence of associations between dietary factors and incidence of type 2 diabetes and to evaluate the strength and validity of these associations.

DESIGN

Umbrella review of systematic reviews with meta-analyses of prospective observational studies.

DATA SOURCES

PubMed, Web of Science, and Embase, searched up to August 2018.

ELIGIBILITY CRITERIA

Systematic reviews with meta-analyses reporting summary risk estimates for the associations between incidence of type 2 diabetes and dietary behaviours or diet quality indices, food groups, foods, beverages, alcoholic beverages, macronutrients, and micronutrients.

RESULTS

53 publications were included, with 153 adjusted summary hazard ratios on dietary behaviours or diet quality indices (n=12), food groups and foods (n=56), beverages (n=10), alcoholic beverages (n=12), macronutrients (n=32), and micronutrients (n=31), regarding incidence of type 2 diabetes. Methodological quality was high for 75% (n=115) of meta-analyses, moderate for 23% (n=35), and low for 2% (n=3). Quality of evidence was rated high for an inverse association for type 2 diabetes incidence with increased intake of whole grains (for an increment of 30 g/day, adjusted summary hazard ratio 0.87 (95% confidence interval 0.82 to 0.93)) and cereal fibre (for an increment of 10 g/day, 0.75 (0.65 to 0.86)), as well as for moderate intake of total alcohol (for an intake of 12-24 g/day v no consumption, 0.75 (0.67 to 0.83)). Quality of evidence was also high for the association for increased incidence of type 2 diabetes with higher intake of red meat (for an increment of 100 g/day, 1.17 (1.08 to 1.26)), processed meat (for an increment of 50 g/day, 1.37 (1.22 to 1.54)), bacon (per two slices/day, 2.07 (1.40 to 3.05)), and sugar sweetened beverages (for an increase of one serving/day, 1.26 (1.11 to 1.43)).

CONCLUSIONS

Overall, the association between dietary factors and type 2 diabetes has been extensively studied, but few of the associations were graded as high quality of evidence. Further factors are likely to be important in type 2 diabetes prevention; thus, more well conducted research, with more detailed assessment of diet, is needed.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42018088106.

Egg consumption, cholesterol intake, and risk of incident stroke in men: the Kuopio Ischaemic Heart Disease Risk Factor Study

BACKGROUND

Epidemiologic studies suggest inverse associations between consumption of egg, a major source of dietary cholesterol, and stroke. However, the evidence of the relation remains limited, especially among carriers of apolipoprotein E4 (apoE4), which influences cholesterol metabolism.

OBJECTIVE

The aim of this study was to investigate associations of egg and cholesterol intakes with risk of stroke and with the major stroke risk factor, blood pressure, in middle-aged and older men from eastern Finland and whether apoE phenotype could modify these associations.

METHODS

A total of 1950 men aged 42-60 y in 1984-1989 were included at the baseline examinations of the prospective population-based Kuopio Ischaemic Heart Disease Risk Factor Study. Data on apoE phenotype were available for 1015 men. Dietary intakes were assessed with 4-d food records at baseline and incident stroke events were assessed by record linkage to hospital discharge registries. Cox proportional hazards regression analyses were used to estimate associations with stroke risk. Associations with baseline blood pressure were evaluated with ANCOVA.

RESULTS

During the mean ± SD follow-up of 21.2 ± 7.2 y, there were 217 incidences of any stroke: 166 of ischemic stroke and 55 of hemorrhagic stroke. Comparing the highest egg intake quartile with the lowest, the multivariable-adjusted HRs were 0.81 for total stroke (95% CI: 0.54, 1.23; P-trend = 0.32), 0.84 for ischemic stroke (95% CI: 0.53, 1.34; P-trend = 0.44), and 0.75 for hemorrhagic stroke (95% CI: 0.32, 1.77; P-trend = 0.40). The respective HRs for the highest cholesterol intake quartile compared with the lowest were 0.86 (95% CI: 0.57, 1.32; P-trend = 0.42), 0.74 (95% CI: 0.46, 1.20; P-trend = 0.32), and 1.10 (95% CI: 0.45, 2.66; P-trend = 0.75). Diastolic blood pressure was 1.6 mm Hg (P-trend = 0.04) lower in the highest egg intake quartile compared with the lowest, but there were no associations with systolic blood pressure or with cholesterol intake. ApoE phenotype (32% had apoE4 phenotype) did not modify the associations.

CONCLUSION

Neither egg nor cholesterol intakes were associated with stroke risk in this cohort, regardless of apoE phenotype.This trial was registered at www.clinicaltrials.gov as NCT03221127.

Mechanism and Potential of Egg Consumption and Egg Bioactive Components on Type-2 Diabetes

Type-2 diabetes (T2D) is one of the major global health challenges and a substantial economic burden. Egg and egg-derived components have been indicated to possess antioxidant, anti-inflammatory, anti-hypertensive, immunomodulatory, and anti-cancer activities. However, the scientific evidence about the benefits of egg on T2D is debatable. The relationship between egg consumption and the risk of T2D from observational epidemiological studies is not consistent. Interventional clinical studies, however, provide promising evidence that egg consumption ameliorates the risk of T2D. Current research progress also indicates that some egg components and egg-derived peptides might be beneficial in the context of T2D, in terms of insulin secretion and sensitivity, oxidative stress, and inflammation, suggesting possible application on T2D management. The current review summarizes recent clinical investigations related to the influence of egg consumption on T2D risk and in vivo and in vitro studies on the effect and mechanism of egg components and egg-derived peptides on T2D.

Comparison of long-term effects of egg yolk consumption under normal and high fat diet on lipid metabolism and fatty acids profile in mice

This study compared the long-term effects of EY consumption under two diet conditions: normal (ND + EY) and high fat diet (HFD + EY), on lipid metabolism in mice. ND + EY did not increase serum triglycerides, total cholesterol hepatic triglyceride concentrations, adipose tissue accumulation and glucose impairment, not leading to fatty liver. HFD + EY markedly decreased adipose tissue accumulation, the triglyceride and total cholesterol, and improved serum HDL-C and blood glucose impairment compared with HFD. PLS-DA analyzes showed both ND + EY and HFD + EY could decrease serum C18:1 and MUFA. HFD + EY could further decrease hepatic C18:2 and PUFA and increase C18:1 and MUFA excretion, which were associated with lower expression of Elovl6 and higher expression of Scd1 in liver. These results suggest that HFD + EY significantly improved dyslipidemia caused by HFD through modifying lipid metabolism, and ND + EY did not adversely affect the biomarkers associated with dyslipidemia risk, but showed less obvious regulation of lipid metabolism than HFD + EY.

Unscrambling the relations of egg and meat consumption with type 2 diabetes risk

Background

Meat intake is associated with increased risk of type 2 diabetes (T2D). It is not clear if egg intake is associated with T2D risk because purported associations may be due to concurrent consumption of eggs with meat.

Objective

Our aim was to differentiate any associations between meat and egg consumption and the risk of T2D.

Design

In this longitudinal study, 55,851 participants of the Adventist Health Study 2 who were free of diabetes provided demographic, anthropometric, and dietary data at baseline. Meat and egg intakes were assessed with a validated quantitative food-frequency questionnaire. Responses to 2 follow-up questionnaires determined incident T2D cases. Multivariate-adjusted logistic regression was used to determine relations between meat and egg intake and incident T2D.

Results

T2D cases identified during a mean 5.3 y of follow-up totaled 2772. Meat intake of >0 to <25 g/d, ≥25 to <70 g/d, and ≥70 g/d significantly increased the risk of T2D compared with no meat intake (OR: 1.29; 95% CI: 1.16, 1.44; OR: 1.42; 95% CI: 1.25, 1.61; and OR: 1.65; 95% CI: 1.39, 1.96, respectively; P-trend < 0.0001). Egg intake compared with no egg intake was not associated with T2D risk. A significant meat-egg interaction (P = 0.019) showed that within every category of egg intake, there was an incremental rise in T2D risk as meat intake increased. However, within categories of meat intake, increasing egg intake did not increase the risk of T2D except among nonmeat-eaters consuming ≥5 eggs/wk (OR: 1.52; 95% CI: 1.09, 2.12).

Conclusions

Meat consumption, but not egg consumption, is independently associated with T2D risk. Egg intake seems not to increase T2D risk further with meat intake. Our findings suggest that the purported egg-T2D risk relation in US populations may be biased due to failure to investigate egg-meat interactions. Further investigations are needed to ascertain T2D risk among nonmeat-eaters with high egg intakes.

Egg Intake Has No Adverse Association With Blood Lipids Or Glucose In Adolescent Girls

OBJECTIVE

Longitudinal data on cardiometabolic effects of egg intake during adolescence are lacking. The current analyses aim to evaluate the impact of usual adolescent egg consumption on lipid levels, fasting glucose, and insulin resistance during late adolescence (age 17-20 years).

METHODS

Data from 1392 girls, aged 9 to 10 at baseline and followed for 10 years, in the National Heart, Lung, and Blood Institute's National Growth and Health Study were used to examine the association between usual egg intake alone and in combination with other healthy lifestyle factors and late adolescent lipid levels, fasting glucose, and insulin resistance, measured as homeostasis model assessment of insulin resistance (HOMA-IR). Diet was assessed using 3-day food records during eight examination cycles. Girls were classified according to usual weekly egg intake, ages 9-17 years: <1 egg/wk (n = 361), 1 to <3 eggs/wk (n = 703), and ≥3 eggs/wk (n = 328). Analysis of covariance modeling was used to control for confounding by other behavioral and biological risk factors.

RESULTS

Girls with low, moderate, and high egg intakes had adjusted low-density lipoprotein cholesterol levels of 99.7, 98.8, and 95.5 mg/dL, respectively (p = 0.0778). In combination with higher intakes of fiber, dairy, or fruits and vegetables, these beneficial effects were stronger and statistically significant. There was no evidence that ≥3 eggs/wk had an adverse effect on lipids, glucose, or HOMA-IR. More active girls who consumed ≥3 eggs/wk had the lowest levels of insulin resistance.

CONCLUSION

These results suggest that eggs may be included as part of a healthy adolescent diet without adverse effects on glucose, lipid levels, or insulin resistance.

Egg consumption is associated with a lower risk of type 2 diabetes in middle-aged and older men

BACKGROUND/OBJECTIVES

This prospective study examined gender-specific associations between egg intake and the risk of developing type 2 diabetes using data from a large-scale cohort study.

SUBJECTS/METHODS

A total of 7,002 Korean adults (40–69 years) without type 2 diabetes at baseline were analyzed. Dietary intake was evaluated by a food frequency questionnaire administered at baseline (2001–2002) and the second follow-up examination (2005–2006). Type 2 diabetes was diagnosed as a fasting glucose concentration ≥ 126 mg/dL or current use of glucose-lowering medications or insulin injection. Multivariate Cox proportional hazard models were used to calculate hazard ratios (HRs) with 95% confidence intervals (CIs) for incident type 2 diabetes according to egg consumption or cholesterol intake.

RESULTS

During a 14-year follow up period, 857 subjects developed type 2 diabetes. In men, frequent egg intake (2- < 4 servings/week) was associated with a 40% lower risk of developing type 2 diabetes than infrequent egg intake (0- < 1 serving/week) (HR = 0.60, 95% CI: 0.37–0.97), whereas no association between egg intake and incidence of type 2 diabetes was observed in women (HR = 0.61, 95% CI: 0.27–1.37). There was no association between cholesterol intake and risk of incident type 2 diabetes in either men or women.

CONCLUSIONS

Egg consumption was inversely related to the risk of incident type 2 diabetes in men, but not in women, suggesting gender differences in the relationship between diet and disease risk.

Dietary Cholesterol Intake Is Not Associated with Risk of Type 2 Diabetes in the Framingham Offspring Study

Identification of diet and lifestyle risk factors for prevention of type 2 diabetes mellitus (T2DM) is of great importance. The specific role of dietary cholesterol (DC) in T2DM risk is unclear. This study uses data from 2192 Framingham Offspring Study subjects to estimate the effects of DC alone and in combination with markers of a healthy diet and other lifestyle factors on fasting glucose and risk of T2DM or impaired fasting glucose (IFG) over 20 years of follow-up. Dietary data were derived from two sets of three-day food records. Statistical methods included mixed linear regression and Cox proportional hazard's modeling to adjust for confounding. There were no statistically significant differences in glucose levels over 20 years of follow-up across DC intake categories (.

Association between Egg Consumption and Metabolic Disease

The effect of high egg intake on metabolic syndrome (MetS), a major risk factor for cardiovascular disease (CVD), has not been clearly elucidated. This study was conducted to review the literature related to egg consumption and the risk of metabolic disease as well as to examine the association between high egg intake and MetS in Korean adults. A literature review was conducted using published papers in PubMed and EMBASE through December 2017. We have reviewed 26 articles, which were associated with egg consumption and metabolic diseases, and found that the results were controversial. Therefore, we analyzed data from 23,993 Korean adults aged 19 yrs and older. MetS was defined based on criteria from the Adult Treatment Panel III. Egg consumption of 4-6 times/wk and 1 time/day were significantly associated with reduced prevalence of MetS (Odds ratio (OR)=0.82; 95% Confidence interval (CI)=0.71-0.95 for 4-6 times/wk, OR=0.83; 95% CI=0.69-0.99 for 1 time/day) compared to those who consumed eggs less than once monthly. However, consuming two or more eggs per day was not associated with MetS. As for the components of MetS, an egg intake of once daily decreased the prevalence of abdominal obesity and an intake of 2-7 eggs weekly was shown to prevent a reduction in the high-density lipoprotein cholesterol levels. This study suggests that while consuming eggs 4-7 times weekly is associated with a lower prevalence of MetS, consuming two or more eggs daily is not associated with a reduced risk for MetS.

Food groups and risk of type 2 diabetes mellitus: a systematic review and meta-analysis of prospective studies

The aim of this systematic review and meta-analysis was to synthesize the knowledge about the relation between intake of 12 major food groups and risk of type 2 diabetes (T2D). We conducted a systematic search in PubMed, Embase, Medline (Ovid), Cochrane Central, and Google Scholar for prospective studies investigating the association between whole grains, refined grains, vegetables, fruits, nuts, legumes, eggs, dairy, fish, red meat, processed meat, and sugar-sweetened beverages (SSB) on risk of T2D. Summary relative risks were estimated using a random effects model by contrasting categories, and for linear and non-linear dose–response relationships. Six out of the 12 food-groups showed a significant relation with risk of T2D, three of them a decrease of risk with increasing consumption (whole grains, fruits, and dairy), and three an increase of risk with increasing consumption (red meat, processed meat, and SSB) in the linear dose–response meta-analysis. There was evidence of a non-linear relationship between fruits, vegetables, processed meat, whole grains, and SSB and T2D risk. Optimal consumption of risk-decreasing foods resulted in a 42% reduction, and consumption of risk-increasing foods was associated with a threefold T2D risk, compared to non-consumption. The meta-evidence was graded “low” for legumes and nuts; “moderate” for refined grains, vegetables, fruit, eggs, dairy, and fish; and “high” for processed meat, red meat, whole grains, and SSB. Among the investigated food groups, selecting specific optimal intakes can lead to a considerable change in risk of T2D.

Emerging Evidence for the Importance of Dietary Protein Source on Glucoregulatory Markers and Type 2 Diabetes: Different Effects of Dairy, Meat, Fish, Egg, and Plant Protein Foods

Observational studies provide evidence that a higher intake of protein from plant-based foods and certain animal-based foods is associated with a lower risk for type 2 diabetes. However, there are few distinguishable differences between the glucoregulatory qualities of the proteins in plant-based foods, and it is likely their numerous non-protein components (e.g., fibers and phytochemicals) that drive the relationship with type 2 diabetes risk reduction. Conversely, the glucoregulatory qualities of the proteins in animal-based foods are extremely divergent, with a higher intake of certain animal-based protein foods showing negative effects, and others showing neutral or positive effects on type 2 diabetes risk. Among the various types of animal-based protein foods, a higher intake of dairy products (such as milk, yogurt, cheese and whey protein) consistently shows a beneficial relationship with glucose regulation and/or type 2 diabetes risk reduction. Intervention studies provide evidence that dairy proteins have more potent effects on insulin and incretin secretion compared to other commonly consumed animal proteins. In addition to their protein components, such as insulinogenic amino acids and bioactive peptides, dairy products also contain a food matrix rich in calcium, magnesium, potassium, trans-palmitoleic fatty acids, and low-glycemic index sugars-all of which have been shown to have beneficial effects on aspects of glucose control, insulin secretion, insulin sensitivity and/or type 2 diabetes risk. Furthermore, fermentation and fortification of dairy products with probiotics and vitamin D may improve a dairy product's glucoregulatory effects.