Habitual consumption of eggs does not alter the beneficial effects of endurance training on plasma lipids and lipoprotein metabolism in untrained men and women

The effect of whole egg consumption on weight and body composition in adults: a systematic review and meta-analysis of clinical trials

BACKGROUND

A limited number of studies have directly examined the effect of whole eggs on body weight and composition in adults, and they have led to inconsistent results. This study aimed to summarize the evidence on the effect of whole egg consumption on body weight and body composition in adults from clinical trials.

METHODS

Online databases were searched from inception to April 2023 for clinical trials that directly or indirectly assessed the effect of whole eggs consumption on anthropometric measures including body weight, body mass index (BMI), waist circumference (WC), and fat-free mass (FFM) in adults. A random effects model was used for meta-analysis.

RESULTS

In total, 32 controlled clinical trials were included in the systematic review. The analyses revealed that whole egg consumption has no significant effect on body weight (n = 22), BMI (n = 13), WC (n = 10), and FFM (n = 4, P > 0.05). The subgroup analyses showed that whole egg consumption has an increasing effect on body weight and BMI in studies that lasted more than 12 weeks and in unhealthy participants (P < 0.05). A significant increasing effect on BMI was found in studies that the control group did not receive any egg (P < 0.05). Moreover, in studies that there was no significant difference in energy intake between the intervention and control groups, weight, and WC were significantly increased (P < 0.05). Additionally, in studies that participants in the control group received another food or supplement, studies with calorie restriction, and studies on healthy subjects, whole egg intake significantly decreased BMI (P < 0.05).

CONCLUSIONS

Although whole egg consumption had no adverse effect on body composition and body weight, in overall, it might increase body weight in long term. Egg consumption beneficially affects BMI in healthy people and during weight loss diet.

SYSTEMATIC REVIEW REGISTRATION

This systematic review and meta-analysis is registered in the International Prospective Register of Systematic Reviews (PROSPERO, Registration number: CRD42022308045).

Is There a Correlation between Dietary and Blood Cholesterol? Evidence from Epidemiological Data and Clinical Interventions

Dietary cholesterol has been a topic of debate since the 1960s when the first dietary guidelines that limited cholesterol intake to no more than 300 mg/day were set. These recommendations were followed for several years, and it was not until the late 1990s when they were finally challenged by the newer information derived from epidemiological studies and meta-analysis, which confirmed the lack of correlation between dietary and blood cholesterol. Further, dietary interventions in which challenges of cholesterol intake were evaluated in diverse populations not only confirmed these findings but also reported beneficial effects on plasma lipoprotein subfractions and size as well as increases in HDL cholesterol and in the functionality of HDL. In this review, we evaluate the evidence from recent epidemiological analysis and meta-analysis as well as clinical trials to have a better understanding of the lack of correlation between dietary and blood cholesterol.

Modification of High-Density Lipoprotein Functions by Diet and Other Lifestyle Changes: A Systematic Review of Randomized Controlled Trials

High-density lipoprotein (HDL) functional traits have emerged as relevant elements that may explain HDL antiatherogenic capacity better than HDL cholesterol levels. These properties have been improved in several lifestyle intervention trials. The aim of this systematic review is to summarize the results of such trials of the most commonly used dietary modifications (fatty acids, cholesterol, antioxidants, alcohol, and calorie restriction) and physical activity. Articles were screened from the Medline database until March 2021, and 118 randomized controlled trials were selected. Results from HDL functions and associated functional components were extracted, including cholesterol efflux capacity, cholesteryl ester transfer protein, lecithin-cholesterol acyltransferase, HDL antioxidant capacity, HDL oxidation status, paraoxonase-1 activity, HDL anti-inflammatory and endothelial protection capacity, HDL-associated phospholipase A2, HDL-associated serum amyloid A, and HDL-alpha-1-antitrypsin. In mainly short-term clinical trials, the consumption of monounsaturated and polyunsaturated fatty acids (particularly omega-3 in fish), and dietary antioxidants showed benefits to HDL functionality, especially in subjects with cardiovascular risk factors. In this regard, antioxidant-rich dietary patterns were able to improve HDL function in both healthy individuals and subjects at high cardiovascular risk. In addition, in randomized trial assays performed mainly in healthy individuals, reverse cholesterol transport with ethanol in moderate quantities enhanced HDL function. Nevertheless, the evidence summarized was of unclear quality and short-term nature and presented heterogeneity in lifestyle modifications, trial designs, and biochemical techniques for the assessment of HDL functions. Such findings should therefore be interpreted with caution. Large-scale, long-term, randomized, controlled trials in different populations and individuals with diverse pathologies are warranted.

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.

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.

Dietary Cholesterol and Plasma Lipoprotein Profiles: Randomized-Controlled Trials

Early work suggested that dietary cholesterol increases plasma total cholesterol concentrations in humans. Given the relationship between elevated plasma cholesterol concentrations and cardiovascular disease risk dietary guidelines have consistently recommended limiting food sources of cholesterol. Current intakes are approaching recommended levels. Recently there have been calls to reassess the importance of continuing to recommend limiting dietary cholesterol. Over the past 10 years there have been a limited number of studies addressing this issue. Striking among these studies is the high degree of variability in background diet, subject characteristics and study design. Within the context of current levels of dietary cholesterol intake, the effect on plasma lipids concentrations, with primary interest in LDL-C cholesterol concentrations, is modest and appears to be limited to population subgroups. In these cases, restrictions in dietary cholesterol intake are likely warranted. The biological determinants of inter-individual variability remain a relatively understudied area.

All-trans retinoic acid alleviates hepatic ischemia/reperfusion injury by enhancing manganese superoxide dismutase in rats

All-trans retinoic acid (atRA) is an active metabolite of vitamin A with antioxidant effects. There have been few reports on the effects of atRA on liver ischemia/reperfusion (I/R) injury. Here we have used a rat liver ischemia/ reperfusion model to analyze the protective effect of atRA. Rats were administered with different does (5-15 mg/kg/d) of atRA intraperitoneally (i.p.) for 14 d before I/R. Partial (70%) hepatic ischemia was induced by clamping the hepatic artery, portal vein, and bile duct to the left and median lobes of the liver using a vascular clamp for 60 min, followed by 24 h of reperfusion. The serum aminotransferase (ALT and AST) and hepatic pathology were used to evaluate I/R injury. The results demonstrate that atRA pretreatment attenuates liver I/R injury by inhibiting the release of malondialdehyde (MDA) and by enhancing the activity of superoxide dismutase (SOD). To gain insight into the mechanism of the SOD up-regulation by atRA, the activity of p38 mitogenactivated protein kinase (p38MAKP) and Akt was measured. The results showed that the phosphorylation of p38MAPK and Akt paralleled the expression of manganese superoxide dismutase (MnSOD). That these activities are related was demonstrated by the addition of a p38 inhibitor which markedly decreased MnSOD levels. Taken together, our data reveal that atRA can protect liver from I/R injury by increaseing MnSOD, which is associated with an increased activity of p38MAPK and Akt.