Differing statistical approaches affect the relation between egg consumption, adiposity, and cardiovascular risk factors in adults

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 effect of steamed potato-wheat bread intake on weight, lipids, glucose, and urinary Na+/K+: A randomized controlled trial in Chinese adults

Steamed potato bread has received much attention from nutritionists and agriculturalists since it became a staple food of China in 2015. Epidemiological studies have indicated that potatoes may cause diabetes and hypertension, but few trials have evaluated this effect. Through a clinical trial, we evaluated the effect of steamed potato bread intake on adults. In total, 49 and 30 individuals were assigned to the intervention and control groups, respectively. Potato-wheat bread (raw wheat flour and cooked potato flour in the ratio 3:7) and steamed wheat bread (100% raw wheat flour) were provided to the intervention and control groups, respectively, once a day for 4 weeks. Compared with the control group, the intervention group showed significant net changes in weight (−0.6 kg; 95% confidence interval [CI]: −1.2, −0.1; p = 0.016), body mass index (BMI, −0.2 kg/m²; 95% CI: −0.4, −0.1; p = 0.020), low-density lipoprotein cholesterol (LDL-c, −0.22 mmol/L; 95% CI: −0.49, −0.01; p = 0.035), and the urinary level of Na⁺/K⁺ (−2.4; 95% CI: −4.1, −0.7; p = 0.007). In conclusion, the steamed potato-wheat bread intake for 4 weeks resulted in decreases in weight, BMI, LDL-c, and the urinary Na⁺/K⁺ level among Chinese adults.

Association between egg intake and blood pressure in the USA: the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP)

OBJECTIVES

To investigate associations of egg intake with blood pressure (BP) and the role of dietary variables and other macro- and micro-nutrients in the association.

DESIGN

We used cross-sectional data for the USA as part of the INTERnational study on MAcro/micronutrients and blood Pressure (INTERMAP). INTERMAP was surveyed between 1996 and 1999, including four 24-h dietary recalls, two 24-h urine collections and eight measurements of systolic BP and diastolic BP (SBP, DBP). Average egg intake (g/d) was calculated. Multivariable linear regression models were used to estimate the association between egg intake (per each 50 g/d or per quintile) and BP. The roles of dietary variables and other macro- and micro-nutrients in this association were also investigated.

SETTING

In the USA.

PARTICIPANTS

In total, 2195 US INTERMAP men and women aged 40-59 years.

RESULTS

Participants were 50 % female, 54 % non-Hispanic White and 16 % non-Hispanic Black. Mean egg intake (sd) in men and women was 30·4(29·8) and 21·6(20·5) g/d, respectively. Adjusting for demographics, socio-economics, lifestyle and urinary Na:K excretion ratios, we found non-linear associations with BP in non-obese women (P-quadratic terms: 0·004 for SBP and 0·035 for DBP).The associations remained after adjusting for dietary variables, macro/micro nutrients or minerals. Dietary cholesterol was highly correlated with egg intake and may factor in the association. No association was found in obese women and in obese or non-obese men.

CONCLUSION

Egg intake was non-linearly associated with SBP and DBP in non-obese women, but not in obese women or men. Underlying mechanisms require additional study regarding the role of obesity and sex.

Whole egg consumption and cognitive function among US older adults

BACKGROUND

Eggs are an affordable food providing many shortfall nutrients with the potential to improve cognitive health. We assessed the relationship between whole egg consumption and cognitive functioning among a US nationally representative sample of older adults.

METHODS

Individual-level data (2816 adults, aged ≥ 60 years) were obtained from the National Health and Nutrition Examination Survey (NHANES) 2011-2012 and 2013-2014 waves. Cognitive assessments included the Consortium to Establish a Registry for Alzheimer's Disease Word List Learning Test (CERAD-WL), Word List Recall Test (CERAD-DR), Animal Fluency Test (AF) and Digit Symbol Substitution Test (DSST). A composite cognitive z-score was constructed based on the individual tests to represent one's overall cognitive functioning. Multiple linear and logistic regressions were performed to examine the effect of whole egg consumption on cognitive functioning, adjusting for individual characteristics and survey design.

RESULTS

Approximately 57% of older adults consumed whole eggs, with an average daily intake of 34 g of whole egg equivalent among consumers. The average z-scores of the CERAD-WL, CERAD-DR, AF and DSST tests were -0.08, 0.23, 0.37 and 0.42, respectively, and the overall composite cognitive z-score was 0.24 among older adults. Regression analyses found that neither whole egg consumption status, nor daily intake quantity was associated with cognitive test scores.

CONCLUSIONS

No association was found between whole egg consumption and cognitive functioning among US older adults. Study limitations included cross-sectional study design and measurement errors. Future studies with longitudinal or experimental design are warranted to examine the possible link between egg consumption and cognition in older adults.

Patterns of Egg Consumption Can Help Contribute to Nutrient Recommendations and Are Associated with Diet Quality and Shortfall Nutrient Intakes

Limited data are available on how eggs are consumed in the typical American eating pattern and the contribution to usual intakes, diet quality and in meeting recommendations. The objectives of the present analysis included identifying how eggs are consumed within U.S. dietary patterns and how these patterns are associated with the usual intakes of shortfall nutrients and diet quality (Healthy Eating Index 2015) using data from the combined National Health and Nutrition Examination Survey (NHANES) from 2001–2016. An additional objective included assessing the differences between egg consumers and egg non-consumers in nutrient intakes and nutrient adequacy. Several egg-containing dietary patterns were identified, and two egg patterns were associated with a greater diet quality compared to a no egg pattern (p < 0.0001). Most egg patterns identified were similar in diet quality scores when compared to the no egg pattern; however, the two egg patterns had lower diet quality scores. Egg consumption combined with a greater intake of total protein foods, seafood and plant protein, total vegetables, total fruit, whole fruit, whole grains and dairy foods, and a lower intake of refined grains and added sugars contributed to an improved diet quality, supporting that no one food is responsible for a healthy dietary pattern. Egg consumers demonstrated significantly higher intakes of dietary fiber, calcium, magnesium, potassium, total choline, vitamin A, vitamin C, vitamin D and vitamin E when compared to egg non-consumers. A comparison of egg consumers and egg non-consumers found egg consumers had significantly less percentages of the population below the EAR for calcium, iron, magnesium, vitamin A, vitamin C and vitamin E. Similarly, the percentage of the population above the recommendations for potassium and choline were greater for egg consumers vs. egg non-consumers. In egg consumers, 24.4% of the population was above the AI for dietary choline when compared to 4.3% of egg non-consumers (p < 0.0001). Findings from the present analysis demonstrate that eggs and egg-containing foods can be an important part of a healthy dietary pattern when balanced accordingly with other nutrient-dense foods.

Eggs as an affordable source of nutrients for adults and children living in food-insecure environments

Food insecurity affects an estimated 12% of households in the United States. Adults and children who experience food insecurity are increased risk for development of metabolic diseases such as type 2 diabetes, obesity, and cardiovascular disease. The negative health outcomes associated with food insecurity are multifactorial; however, many of them may be caused by limited nutritional intake and poor diet quality. Dietary intake of eggs may be an applicable solution for food-insecure families who are challenged by limited nutritional intake. Eggs contain a variety of nutrients that support metabolic health. For instance, eggs are a complete source of high-quality protein and contain 16 vitamins and minerals. Furthermore, eggs are cost efficient. When comparing the relationship between foods on the basis of calories and unit cost, the energy cost of eggs is significantly less when compared with that of other animal-protein foods such as meat, poultry, and fish. However, dietary intake of eggs is controversial in regard to cardiovascular health. Thus, the aim of this review is to summarize the role of eggs in the diet and the impact eggs have on health for adults and children living in a food-insecure environment.

Science dialogue mapping of knowledge and knowledge gaps related to the effects of dairy intake on human cardiovascular health and disease

Dairy has been described as everything from a superfood to a poison; yet, arguments, assumptions, and data justifying these labels are not always clear. We used an issue-based information system, "dialogue mapping™," to summarize scientific points of a live panel discussion on the putative effects of dairy on cardiovascular diseases (CVD) from a day-long session among experts in nutrition and CVD. Dialogue mapping captures relations among ideas to explicitly, logically, and visually connect issues/questions, ideas, pro/con arguments, and agreements, even if discussed at different times. Experts discussed two propositions: for CVD risk, consumption of full-fat dairy products 1) should be minimized, in part because of their saturated fat content, or 2) need not be minimized, despite their saturated fat content. The panel discussed the dairy-CVD relation through blood lipids, diabetes, obesity, energy balance, blood pressure, dairy bioactives, biobehavioral components, and other putative causal pathways. Associations and effects reported in the literature have varied by fat content of dairy elements considered, study design, intake methods, and biomarker versus disease outcomes. Two conceptual topics emerged from the discussion: 1) individual variability: whether recommendations should be targeted only to those at high CVD risk; 2) quality of evidence: whether data on dairy-CVD relations are strong enough for reliable conclusions-positive, negative, or null. Future procedural improvements for science dialog mapping include using singular rather than competing propositions for discussion.

Body Fat Mass, Fat Distribution and Egg Consumption: a Population-Based Study in Chinese Adults

Objective: Egg is the vital source for many nutrients. The present study aimed to evaluate how egg consumption contributes to body fat mass and fat distribution in general Chinese adults.Methods: In a representative study of Chinese adults, 2241 rural adults aged 18-80 years completed physical measurements and semi quantitative food frequency questionnaire (FFQ). Body fat percentage (BF%) was estimated through validated Chinese-specific equations including age, body mass index (BMI), waist circumference (WC), gender and their interaction.Results: The prevalence of excessive body fat and central obesity in males were 44.2% and 31.3%, lower than that in females (60.7% and 36.1%, p < 0.05). 37.3% of lean or normal-weight individuals by BMI experienced excessive body fat given their BF% and 43.5% were central obesity according to WC. In females, egg consumption was associated with better body fat mass and its distribution. Compared with non-consumers, individuals consumed egg >50 g/d had a 34% lower risk of central obesity (OR:0.66, 0.39-0.99) and 38% lower risk of excessive body fat (OR:0.62, 0.37-1.00). There were significant dose-response relationships between egg consumption and overweight with excessive body fat/central obesity (p for linear trend <0.05). However, these associations were not significant in males.Conclusion: Our findings underscore the necessity for future public health guidelines to assess body fat mass and distribution simultaneously in Chinese adults. Egg consumption might be beneficial for weight regulation, especially for overweight with excessive body fat/central obesity in females. Further research is warrant to establish the causal inference.

100% Fruit Juice in Child and Adolescent Dietary Patterns

Objective: Nutritional advice based on strengthening the dietary pattern offers a very different perspective from the reductionist practice of reporting risks or benefits for individual foods.Methods: A healthful dietary pattern can be composed of innumerable different combinations of foods and beverages that collectively and synergistically protect health. Although pure juices lack fiber, juicing retains the majority of health-promoting nutrients and phytochemicals of the whole fruit. Bioactive components of 100% fruit juice have demonstrated positive clinical effects on oxidative markers, inflammation, endothelial reactivity, lipid profiles, hypertension, and platelet aggregation. Fruit juice consumers have higher scores for diet quality. They consume more whole fruit, less added sugar, and greater amounts of vitamin C, magnesium, potassium, and fiber-containing foods than non-consumers.Results: Concerns that 100% fruit juice may be associated with childhood weight gain or metabolic consequences have not been supported by recent systematic reviews and meta-analyses. Juice consumption may be particularly important for the diet quality of lower-socioeconomic-status populations. Over the past 3 decades, as fruit juice intake has fallen substantially, the vacuum has not been filled by a comparable increase in servings of whole fruit, keeping Americans from meeting daily fruit recommendations.Conclusions: Counseling about individual foods without considering their impact on overall diet quality may harm the dietary pattern without discernible health benefits.

Association of eggs with dietary nutrient adequacy and cardiovascular risk factors in US adults

OBJECTIVE

Whole eggs are rich sources of several micronutrients. However, it is not well known how egg consumption contributes to overall nutrient adequacy and how it may relate to CVD risk factors. Therefore, the present study aimed to determine how whole egg consumption contributes to nutrient intakes and to assess its association with CVD risk factors in US adults.

DESIGN

Cross-sectional study.

SETTING

The study was conducted using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2012, a nationally representative survey of the US civilian population.ParticipantsAdults who completed two dietary recalls and provided information on relevant sociodemographic factors were included in the study (n 21 845).

RESULTS

Approximately 73 % of adults were classified as whole egg consumers. Egg consumption was associated with greater intakes of protein, saturated fat, mono- and polyunsaturated fats, Fe, Zn, Ca, Se, choline, and several other vitamins and minerals. Egg consumption was associated with a higher likelihood of meeting or exceeding recommendations for several micronutrients. Egg intake was positively associated with dietary cholesterol consumption, but not with serum total cholesterol (TC) when adjusted for multiple potential confounders. In multiple linear regression analyses, TAG, TAG:HDL-cholesterol and TC:HDL-cholesterol were significantly lower with greater egg consumption. Egg consumption had no significant relationship with LDL-cholesterol or C-reactive protein, but was associated with higher BMI and waist circumference.

CONCLUSIONS

Whole eggs are important dietary contributors of many nutrients and had either beneficial or non-significant associations with most CVD risk biomarkers examined.

Dairy Foods and Body Mass Index over 10-Year: Evidence from the Caerphilly Prospective Cohort Study

The association between dairy product consumption and body mass index (BMI) remains controversial. The aim of the present study was to investigate the association between total dairy, milk, cheese, cream and butter consumption and BMI change over a 10-year follow-up by using long-term follow-up cohort data from the Caerphilly Prospective Cohort Study (CAPS). The CAPS included 2512 men aged 45⁻59 years at baseline, who were followed up at 5-year intervals for over 20-year. A semi-quantitative food frequency questionnaire estimated the intake of dairy consumption, including milk, cheese, cream and butter at baseline, 5-year and 10-year follow-up. In total, men free of cardiovascular disease, diabetes and cancer (n = 1690) were included in current analysis. General linear regression and logistic regression were used for data analysis. The results showed higher cheese consumption was associated with lower BMI at the 5-year follow-up (p = 0.013). There was no evidence that higher consumption of total dairy, milk, cream and butter were significantly associated with BMI during the over the 10-year following-up. This study suggest that cheese consumption have beneficial effects on lowering BMI, which needs further investigation.

Obesity and neurological disorders: Dietary perspective of a global menace

Obesity is considered a major public health concern throughout the world among children, adolescents, as well as adults and several therapeutic, preventive and dietary interventions are available. In addition to life style changes and medical interventions, significant milestones have been achieved in the past decades in the development of several functional foods and dietary regimens to reduce this menace. Being a multifactorial phenomenon and related to increased fat mass that adversely affects health, obesity has been associated with the development of several other co-morbidities. A great body of research and strong scientific evidence identifies obesity as an important risk factor for onset and progression of several neurological disorders. Obesity induced dyslipidaemia, metabolic dysfunction, and inflammation are attributable to the development of a variety of effects on central nervous system (CNS). Evidence suggests that neurological diseases such as Parkinson's disease and Alzheimer's disease could be initiated by various metabolic changes, related to CNS damage, caused by obesity. These metabolic changes could alter the synaptic plasticity of the neurons and lead to neural death, affecting the normal physiology of CNS. Dietary intervention in combination with exercise can affect the molecular events involved in energy metabolism and synaptic plasticity and are considered effective non-invasive strategy to counteract cognitive and neurological disorders. The present review gives an overview of the obesity and related neurological disorders and the possible dietary interventions.

Association between egg consumption and cardiovascular disease events, diabetes and all-cause mortality

Purpose

The association between egg consumption and cardiovascular disease (CVD) or type 2 diabetes (T2D) remains controversial. We investigated the association between egg consumption and risk of CVD (primary outcome), T2D and mortality in the Caerphilly prospective cohort study (CAPS) and National Diet and Nutritional Survey (NDNS).

Methods

CAPS included 2512 men aged 45–59 years (1979–1983). Dietary intake, disease incidence and mortality were updated at 5-year intervals. NDNS included 754 adults aged 19–64 years from 2008 to 2012.

Results

Men free of CVD (n = 1781) were followed up for a mean of 22.8 years, egg consumption was not associated with new incidence of CVD (n = 715), mortality (n = 1028) or T2D (n = 120). When stroke (n = 248), MI (n = 477), heart failure (n = 201) were investigated separately, no associations between egg consumption and stroke and MI were identified, however, increased risk of stroke in subjects with T2D and/or impaired glucose tolerance (IGT, fasting plasma glucose ≥ 6.1 mmol/L), adjusted hazard ratios (95% CI) were 1.0 (reference), 1.09 (0.41, 2.88), 0.96 (0.37, 2.50), 1.39 (0.54, 3.56) and 2.87 (1.13, 7.27) for egg intake (n) of 0 ≤ n ≤ 1, 1 < n ≤ 2, 2 < n ≤ 3, 3 < n < 5, and n ≥ 5 eggs/wk, respectively (P = 0.01). In addition, cross-sectional analyses revealed that higher egg consumption was significantly associated with elevated fasting glucose in those with T2D and/or IGT (CAPS: baseline P = 0.02 and 5-year P = 0.04; NDNS: P = 0.05).

Conclusions

Higher egg consumption was associated with higher blood glucose in subjects with T2D and/or IGT. The increased incidence of stroke with higher egg consumption among T2D and/or IGT sub-group warrants further investigation.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-017-1566-0) contains supplementary material, which is available to authorized users.

Egg consumption, cardiovascular diseases and type 2 diabetes

Eggs are rich in nutrients and a source of essential fatty- and amino acids, and the food item with highest cholesterol content. Since the 1970s dietary recommendations have advised limiting egg intake to 2-4 a week for the healthy population, and in those diagnosed with cardiovascular disease (CVD) and type 2 diabetes (T2D) an even more restricted consumption. The aim of the present paper was to assess the recommendation to lower the dietary intake of cholesterol and especially the intake of egg to reduce the risk of CVD and T2D. We performed three web-based literature searches on human studies (observational and interventional) published within the past 10 years during spring 2015. High-quality intervention studies have found nonsignificant effects of increasing the consumption of eggs on risk markers for CVD and T2D in healthy subjects and subjects with T2D. The risk associations found in the observational studies are more likely to be attributed to a dietary pattern often accompanying high egg intake and/or the cluster of other risk factors in people with high egg consumption. Dietary patterns, physical activity and genetics affect the predisposition of CVD and T2D more than a single food item as eggs. In conclusion, up to seven eggs per week can safely be consumed, but in patients with established CVD or T2D only with special emphasis on a healthy lifestyle.

Time Trends and Patterns of Reported Egg Consumption in the U.S. by Sociodemographic Characteristics

Eggs have the potential to contribute essential nutrients to nutritionally vulnerable populations on limited food budgets. Further research is needed to better understand patterns of egg consumption across diverse sociodemographic groups in order to inform clinical practice to improve nutrient adequacy. Data on demographics and egg intake of 29,694 U.S. adults were obtained from the National Health and Nutrition Examination Survey, 2001-2012. The National Cancer Institute's usual intake methodology was used to estimate the distribution of egg intake. Linear and logistic regression models were used to test for time trends in egg consumption and for differences between sociodemographic groups. The proportion of the U.S. population, overall (21%-22%; p = 0.311) and by sociodemographic group (p > 0.05 for all groups), that reported consuming eggs remained unchanged from 2001 to 2012. Mean egg consumption increased overall from 23.0 (95% CI, 20.8-25.2) g/day in 2001-2002 to 25.5 (22.7-28.4) g/day in 2011-2012 (p = 0.012), but not among food insecure individuals (p = 0.816) and Supplemental Nutrition Assistance Program (SNAP) participants (p = 0.399). No differences in the odds of egg consumption were observed by income level, food security status, or SNAP participation status (p > 0.05 for all groups). Given the nutritional benefits of eggs, as well as their low cost and culinary versatility, the results presented here have important implications for reducing disparities in health outcomes and diet quality, in particular among food insecure individuals and SNAP participants. Further research is needed to examine factors that influence egg consumption and associated nutrient intake, and to identify potential barriers to increasing egg consumption, such as egg price changes, across diverse sociodemographic groups.

Egg consumption and heart health: A review

Cardiovascular disease is the leading cause of death in the United States. Until recently, reducing dietary cholesterol has been a part of the American Heart Association (AHA) and American College of Cardiology (ACC) guidelines on lifestyle management, despite inconclusive evidence to support the recommendation. Considering eggs are a rich source of dietary cholesterol (typically containing 141-234 mg per egg), individuals with increased risk for CVD are advised not to consume eggs. Furthermore, based on the 2012 AHA/ACC guidelines, individuals with lower risk for CVD have previously been advised to avoid consuming eggs due to the high content of dietary cholesterol. Rather than strictly limiting cholesterol intake, the AHA and ACC guidelines now recommend dietary patterns that emphasize fruits, vegetables, whole grains, low-fat dairy products, poultry, fish, and nuts as an approach to favorably alter blood lipid levels. Of note, the 2015-2020 Dietary Guidelines for Americans have removed the recommendation of limiting cholesterol intake to no more than 300 mg per day; however, the guidelines advise that individuals should eat as little dietary cholesterol as possible while consuming a healthy eating pattern. The purpose of this review is to summarize the documented health risks of egg consumption in individuals with low and high risk for CVD and determine whether current recommendations are warranted based on the available literature. We also aim to provide guidance for future studies that will help further elucidate the health modulating effect of eggs.

Potatoes and risk of obesity, type 2 diabetes, and cardiovascular disease in apparently healthy adults: a systematic review of clinical intervention and observational studies

BACKGROUND

Potatoes have been related to increased risks of obesity, type 2 diabetes (T2D), and cardiovascular disease (CVD) mainly because of their high glycemic index.

OBJECTIVE

We conducted a systematic review to evaluate the relation between intake of potatoes and risks of obesity, T2D, and CVD in apparently healthy adults.

DESIGN

MEDLINE, Embase, the Web of Science, and the Cochrane Central Register of Controlled Trials were searched for intervention and prospective observational studies that investigated adults without any known illnesses at baseline, recorded intake of potatoes, and measured adiposity (body weight, body mass index, or waist circumference), cases of T2D, cases of cardiovascular events, or risk markers thereof.

RESULTS

In total, 13 studies were deemed eligible; 5 studies were related to obesity, 7 studies were related to T2D, and one study was related to CVD. Only observational studies were identified; there were 3 studies with moderate, 9 studies with serious, and one study with critical risk of bias. The association between potatoes (not including french fries) and adiposity was neutral in 2 studies and was positive in 2 studies. French fries were positively associated with adiposity in 3 of 3 studies. For T2D, 2 studies showed a positive association, whereas 5 studies showed no or a negative association with intake of potatoes and T2D. French fries were positively associated with T2D in 3 of 3 studies that distinguished this relation. For CVD, no association was observed.

CONCLUSIONS

The identified studies do not provide convincing evidence to suggest an association between intake of potatoes and risks of obesity, T2D, or CVD. French fries may be associated with increased risks of obesity and T2D although confounding may be present. In this systematic review, only observational studies were identified. These findings underline the need for long-term randomized controlled trials. This trial was registered at the PROSPERO International prospective register of systematic reviews (www.crd.york.ac.uk/PROSPERO/) as CRD42015026491.

Eggs: good or bad?

Eggs have one of the lowest energy to nutrient density ratios of any food, and contain a quality of protein that is superior to beef steak and similar to dairy. From a nutritional perspective, this must qualify eggs as 'good'. The greater burden of proof has been to establish that eggs are not 'bad', by increasing awareness of the difference between dietary and blood cholesterol, and accumulating sufficient evidence to exonerate eggs from their associations with CVD and diabetes. After 60 years of research, a general consensus has now been reached that dietary cholesterol, chiefly from eggs, exerts a relatively small effect on serum LDL-cholesterol and CVD risk, in comparison with other diet and lifestyle factors. While dietary guidelines have been revised worldwide to reflect this view, associations between egg intake and the incidence of diabetes, and increased CVD risk in diabetes, prevail. These associations may be explained, in part, by residual confounding produced by other dietary components. The strength of evidence that links egg intake to increased CVD risk in diabetes is also complicated by variation in the response of serum LDL-cholesterol to eggs and dietary cholesterol in types 1 and 2 diabetes. On balance, the answer to the question as to whether eggs are 'bad', is probably 'no', but we do need to gain a better understanding of the effects of dietary cholesterol and its association with CVD risk in diabetes.

Egg consumption and risk of incident type 2 diabetes: a dose–response meta-analysis of prospective cohort studies

Experimental data suggest that egg intake could have a beneficial impact on several risk factors for type 2 diabetes. In contrast, some recent epidemiological studies have concluded that egg consumption may increase diabetes risk. We performed a dose–response meta-analysis of prospective cohorts on the relation of egg consumption with incident type 2 diabetes. We searched for cohort studies that assessed egg consumption and diabetes risk up to June 2015. We identified 416 articles and extracted data independently and in duplicate from ten eligible studies. We used random-effects generalised least squares models for pooled dose–response estimation based on thirteen estimates. Our study included 251 213 individuals and 12 156 incident type 2 diabetes cases. Egg intake was associated with incident type 2 diabetes (risk ratio (RR)/egg per d 1·13; 95 % CI 1·04, 1·22). We identified study location as a major source of heterogeneity. For studies conducted in the USA, we observed a stronger association (RR 1·47; 95 % CI 1·32, 1·64), whereas results were null for studies conducted elsewhere. Studies considered to be of high quality yielded null findings (RR 0·94; 95 % CI 0·74, 1·19). The association of egg intake with increased risk of incident type 2 diabetes may be restricted to US cohort studies. There are limited data to support a biological mechanism that could underlie this association; thus, the possibility that these results may be due to residual confounding by dietary behaviours restricted to certain populations cannot be excluded.

Nutrient Intake, Diet Quality, and Weight Measures in Breakfast Patterns Consumed by Children Compared with Breakfast Skippers: NHANES 2001-2008

Most studies showing that children consuming breakfast have better nutrient intakes, diet quality, and lower weight than breakfast skippers have the incorrect premise that breakfast meals are homogeneous. The purpose of this study was to classify breakfast meals into patterns and determine the association of the breakfast patterns with daily and breakfast nutrient intakes, diet quality, and weight. Data from children (2-18 years of age; N = 14,200) participating in the National Health and Nutrition Examination Survey 2001-2008 were used. Intake was determined from one day 24-hour dietary recalls. Diet quality was measured using the Healthy Eating Index-2005 (HEI-2005). Body mass index (BMI) z-scores were determined. Twelve patterns (including No Breakfast [∼19% of population]), explaining 63% of the variance in energy from breakfast, were examined. Covariate adjusted general linear models were used to compare outcome variables of consumers of different patterns with breakfast skippers. The p value was Bonferroni corrected (< 0.05/12 = < 0.0042). Consumers of the Eggs/Grain/Meat, Poultry, Fish (MPF)/ Fruit Juice (FJ) and MPF/ Grain/FJ patterns showed higher daily intakes of saturated fats, solid fats, and sodium and lower daily intakes of added sugars than breakfast skippers. Consumers of most breakfast patterns showed higher daily intakes of some nutrients of public health concern (dietary fiber, vitamin D, calcium, and potassium); however, those consuming the Grain or MPF/Grain/FJ pattern did not. Consumers of the Grain/Lower Fat Milk (LFM)/Sweets/FJ, Presweetened (PS) Ready-to-eat Cereal (RTEC)/ LFM, RTEC/LFM, Cooked Cereal/Milk/FJ, and Whole Fruit patterns had higher total HEI-2005 scores than breakfast skippers; those consuming the MPF/ Grain/FJ pattern had lower diet quality than breakfast skippers. Consumption of the Grain/ LFM/Sweets/FJ, PSRTEC/whole milk, Soft Drinks/ FJ/Grain/Potatoes, RTEC/whole milk, and Cooked Cereal/ Milk/ FJ patterns was associated with lower BMI z-scores than seen in breakfast skippers. There are dietary and weight advantages of consuming breakfast, especially breakfasts that include grains, cereals, LFM, and fruit/ FJ, in contrast to the potential adverse effects of skipping breakfast.

Research gaps in evaluating the relationship of meat and health

Humans evolved as omnivores and it has been proposed that cooking meat allowed for evolution of larger brains that has led to our success as a species. Meat is one of the most nutrient dense foods, providing high-quality protein, heme iron, zinc, and vitamins B6 and B12. Despite these advantages, epidemiologic studies have linked consumption of red or processed meat with obesity, type 2 diabetes, cardiovascular diseases, and cancers of multiple organs. Most observational studies report small, increased relative risks. However, there are many limitations of such studies including inability to accurately estimate intake, lack of prespecified hypotheses, multiple comparisons, and confounding from many factors - including body weight, fruit/vegetable intake, physical activity, smoking, and alcohol - that correlate significantly either positively or negatively with meat intake and limit the reliability of conclusions from these studies. The observational studies are heterogeneous and do not fulfill many of the points proposed by AB Hill in 1965 for inferring causality; his most important factor was strength of the association which in dietary studies is usually <1.5 but is not considered adequate in virtually all other areas of epidemiology outside nutrition. Accepting small, statistically significant risks as "real" from observational associations, the field of nutrition has a long list of failures including beta-carotene and lung cancer, low-fat diets and breast cancer or heart disease that have not been confirmed in randomized trials. Moderate intake of a variety of foods that are enjoyed by people remains the best dietary advice.