Eggs are back on the menu: study finds no connection to obesity when consumed in moderation

Eggs are back on the menu: study finds no connection to obesity when consumed in moderation

New research debunks myths surrounding eggs and obesity. They show how moderate consumption promotes health while highlighting the best cooking methods for maximum nutritional value.

Phospholipids derived from eggs: Components such as lecithin not only help reduce cholesterol absorption but also support fat metabolism, helping to prevent obesity and related health risks.

In a recent review published in the magazinePoultry ScienceResearchers conducted a comprehensive study to find out whether frequent egg consumption can increase the risk of obesity in healthy people. They reviewed two decades of nutritional literature between 2002 and 2022 and found that most nutrients derived from eggs (lecithins, apolipoproteins, and unsaturated fatty acids) are not associated with an increased risk of obesity. Surprisingly, most research suggests that these nutrients reduce the likelihood of obesity by regulating fat metabolism. The research also noted that individual responses to dietary cholesterol vary. Some people are classified as “high responders” who may experience significant changes in cholesterol levels, highlighting the importance of personalized nutritional advice.

In particular, it has been found that the choice of cooking method significantly alters the nutritional composition of eggs, thereby significantly influencing their physiological effects on human health. In particular, soft-boiled eggs have been identified as the optimal method as they contain the most beneficial nutrients compared to hard-boiled or fried eggs. In summary, seven to eight eggs per week were not associated with an increased risk of obesity in healthy people.

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Cooking Methods and Nutrient Preservation: Frying and overheating eggs results in significant nutrient loss, while soft cooking preserves essential vitamins, lipids and bioactive compounds, making it the healthiest cooking method.

Obesity is one of the biggest health problems in modern society. The World Health Organization (WHO) estimates that one in eight people live with the disease. The condition is characterized by unnatural weight (body mass index [BMI] > 30). It is associated with numerous chronic and potentially life-threatening diseases, including cardiovascular disease (CVD), type 2 diabetes (T2D), liver disease, and certain cancers.

Worryingly, the prevalence of obesity is increasing at an unprecedented rate. Current forecasts assume that more than half of the world's population will be living with the chronic disease by 2035. Previous research has found that suboptimal health behaviors, particularly diet, are the leading cause of obesity.

Eggs provide a common, affordable, and commonly consumed source of high-quality protein, nutrients, and essential amino acids. Unfortunately, eggs are high in cholesterol (approximately 186 mg per large egg), a significant risk factor for obesity. While several studies suggest that moderate egg consumption (1-2 eggs daily) does not significantly affect blood cholesterol levels, there is considerable variation in individual responses, with some individuals metabolizing dietary cholesterol more effectively than others. The lack of comprehensive reviews on this topic leaves clinicians, nutritionists, and consumers alike unclear about the health effects of egg-derived nutrients and their individual or additional obesity risks.

About the review

The present research aimed to elucidate the association between egg consumption (in healthy people) and the occurrence of obesity, with a focus on the individual and summative effects of various egg-derived nutrients, and so should inform future dietary guidelines on the benefits and harms of egg consumption (including daily/weekly recommended intake guidelines). Publication screening was conducted via a custom keyword search in three online repositories of scientific literature – Scopus, PubMed and Google Scholar. These repositories were queried between 2002 and 2022 for relevant articles, publications, reviews or meta-analyses.

Identified publications were reviewed to eliminate duplicates, non-English language publications, short communications, case reports, or publications with incomplete information. Subsequently, the synthesized review included publications that succinctly define obesity and list its health risks, global consumption trends, current prevalence, and future projections. It then identifies and compiles data on egg-derived nutrients commonly used in obesity research, particularly cholesterol, lecithin, fatty acids, proteins, vitamins and minerals.

Check the results

Global trends in egg consumption: China leads the world in egg production and consumption with an annual per capita consumption of 298 eggs, highlighting the role of eggs as a staple in a diverse diet.

The research identified cholesterol as the most controversial nutrient in the egg obesity discourse, but highlights that endogenous modulation of externally ingested cholesterol by the healthy human body is more than sufficient to explain moderate egg consumption (~1–2 eggs daily). Previous research has failed to demonstrate a concrete connection between moderate egg consumption and obesity or overweight (BMI > 25). These conclusions are supported by summary statistics showing that <10 eggs per week does not significantly alter the risk of obesity.

In contrast, eggs are one of the healthiest sources of proteins and essential amino acids and also contain significant amounts of vitamins and minerals, highlighting their overall health benefits. “When weekly intake is between seven and eight, people with a normal weight BMI of <25 are not at risk of overweight or obesity and maximize their nutrient intake,” the authors explained.

Recent research suggests that cooking methods can alter the nutrient profile of eggs, with frying and overheating leading to nutrient losses. Soft-boiled eggs, which contain both lipids and bioactive nutrients, were recommended as the most nutritious preparation method. However, uncooked egg whites can pose risks due to anti-nutrient factors and bacterial contamination. Current dietary recommendations consider boiled or soft-boiled eggs to be the healthiest, although further targeted research is needed to confirm these assumptions.

Conclusions

Vitamin powerhouse: Eggs contain almost every vitamin except vitamin C, with the yolk providing fat-soluble vitamins such as A, D, E and K, which are essential for various body functions.

The present comprehensive review highlights the lack of evidence supporting an association between frequent but moderate egg consumption and an increased risk of obesity. The limited literature examining the cholesterol content of eggs with adverse health consequences shows that the endogenous cholesterol modulation mechanisms of the human body are sufficient to explain the excess cholesterol derived from eggs. In contrast, eggs are one of the healthiest sources of proteins, essential amino acids and micronutrients that have positive effects on human health.

In conclusion, the health benefits of eggs make them an ideal addition to human's daily diet. While people with pre-existing cholesterol conditions (high reactivity or high baseline levels) may need to limit their weekly egg consumption, healthy individuals should have no concerns with fewer than 10 eggs per week. Further research is needed to examine how cultural dietary habits and egg consumption affect the risk of obesity, as eating habits vary significantly between populations. Further research is needed to determine the best cooking methods for optimal egg nutrient absorption.

No systematic review, results not shown, clearly industry influenced. Poultry Science??

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