Eggs as Functional Foods and Nutraceuticals for Human Health

Jianping Wu

• Publisher: Royal Society of Chemistry
• Year: 2019
• ISBN:
  9781788017794
• Edition: 1
• Topic: Medicine
• Subtopic: Nutrition, Dietics & Bariatrics

Often described as 'nature's perfect food', perceptions of egg consumption and human health have evolved substantially over the past decades, in particular dietary guidelines no longer include a limit for dietary cholesterol and recommend eggs as part of healthy eating patterns. This book presents the opportunities for processing eggs to produce value-added food, nutritional, biomedical, functional food, and nutraceutical applications. It provides new evidence around egg consumption with respect to cardiovascular diseases, metabolic syndrome, weight management, mental development, eye, muscle, and ageing health. It also highlights the new discovery regarding egg bioactives that are relevant to anti-oxidants, anti-inflammation, cardiovascular and bone health, anti-microbial and anti-viral activities.

Appealing to food scientists, food chemists, researchers in human nutrition specialising in eggs and dairy nutrition, and those involved in egg production, this book is reflecting the trends and innovations in this area of research.

CHAPTER 1

Eggs as Part of a Healthy Eating Pattern

Rylee T. Ahnen ^a and Joanne L. Slavin^*a

^a Department of Food Science and Nutrition, University of Minnesota, 166 FSCN, 1334 Eckles Ave, St. Paul, MN 55408, USA
^*E-mail:[email protected]

The historical recommendations for egg consumption have been confusing to consumers and have resulted in many individuals wondering whether or not eggs should be considered part of a healthful diet. This chapter is a review of the dietary recommendations concerning eggs, the research that eventually changed those recommendations, and the positive health benefits of incorporating eggs into the diet. Eggs as a source of high-quality protein, as a source of choline, and as a tool for satiety and weight management are each discussed, as is potential for additional improvement of the nutrient profile of eggs through fortification. While additional research may be needed to further demonstrate the association between eggs and certain positive health outcomes, the body of scientific evidence surrounding eggs supports the belief that they are healthful for human consumers and should be considered part of a healthy dietary pattern.

1.1 Introduction

Eggs have long been regarded for their nutrient density, providing consumers with a high-quality protein source in addition to a wide variety of critical minerals, vitamins, and trace elements. ¹ Compared to other significant sources of dietary proteins, eggs provide relatively high levels of folate, biotin, choline, and vitamin A for a relatively small number of calories, and also deliver an impressive combination of amino acids. ^2,3 Additionally, eggs serve as an affordable protein and nutrient source. As reported in the Nutrient Rich Foods Index, and again in a review by Iannotti et al. in 2014, eggs are the most affordable protein source in the United States when included as part of a comprehensive food list. ^4,5

However, despite the wide acceptance that eggs are an affordable and nutrient-rich food, the American public has been reticent to accept eggs as part of a healthy eating pattern owing to concerns about cholesterol intake. In fact, recent studies examining consumer data from the National Health and Nutrition Examination Survey (NHANES) found that from 2001 to 2012 the overall proportion of the U.S. population who consumed eggs regularly (21–22%; p = 0.311) remained unchanged. ⁶ Research examining consumer perceptions about eggs and the barriers to their consumption found that egg consumption has declined owing to the perceived association most consumers make between the consumption of eggs and dietary cholesterol. ^7,9

While the perception that egg consumption is associated with dietary cholesterol and, therefore, is associated with increased levels of plasma cholesterol has been supported by recommendations put forth by the U.S. government and reputable public health organizations in the past, recent examinations of the body of literature concerning egg consumption suggest that eggs should be considered a healthy part of the diet. In the following sections, we will discuss the history of dietary recommendations that resulted in the long-held belief that egg consumption should be undertaken in moderation, the changes in the American dietary pattern that occurred as a result of those recommendations, several of the potential health benefits associated with eggs that make them a key part of the modern healthy dietary pattern, as well as the potential for eggs to be enriched in order to even better serve as a component of healthy diets.

1.2 Dietary Recommendations Concerning Eggs

1.2.1 Introduction

Dietary recommendations concerning the consumption of eggs have been part of the public's understanding of nutrition for nearly half a century, dating back to the 1968 recommendation from the American Heart Association (AHA) that individuals limit their intake of dietary cholesterol to no more than 300 mg per day in order to reduce their risk of cardiovascular disease (CVD), and that individuals consume no more than three whole eggs per week in order to meet that recommendation. ¹⁰ That recommendation created a paradigm shift in the way the American public viewed the consumption of eggs, providing the average consumer with an easy to understand dietary intervention they could undertake in order to improve their lifestyle, and resulted in an overall decline in the per capita consumption of eggs in the years that followed. ¹¹ This recommendation against the consumption of dietary cholesterol, and eggs in particular, persisted for decades.

1.2.2 Dietary Recommendations from 1950 to 2010

Dietary recommendations in the United States took their first form in a report published by the American Heart Association in 1957 that posited, in somewhat uncertain terms, that the changing diet of the average American may have contributed to the increased pathogenesis of atherosclerosis in the United States. ¹² As noted by Kritchevsky in The Journal of Nutrition, the American Heart Association released another report four years later in 1961 which focused on dietary fats and their relationship to heart attacks and strokes, putting forth recommendations for dietary modifications that began modeling the current construction of our modern dietary recommendations. ^13,14 Seven years later, in 1968, the American Heart Association put forth a report that set the standard for dietary cholesterol and egg consumption that would persist for decades – that Americans should limit dietary cholesterol to no more than 300 mg per day and should not consume more than three egg yolks per week. ¹⁰

Less than a decade after the American Heart Association recommended that consumers limit their dietary intake of eggs in order to achieve a dietary pattern that protected them against CVD, the United States government began the process of establishing federally sanctioned dietary guidelines for every United States citizen. The first iteration of these guidelines was created and published in 1977 by the U.S. Senate Select Committee on Nutrition and Human Needs, which mirrored the American Heart Association recommendation of limiting dietary cholesterol to 300 mg per day and suggested that Americans limit their intake of eggs as a means of achieving that goal. ¹⁵ Following the publication of the report from the U.S. Select Committee on Nutrition and Human Needs, the federal government took steps to formalize the process of creating and disseminating dietary recommendations to the American public and established the Dietary Guidelines for Americans, which have been issued twice a decade since 1980 and provide citizens of the United States with recommendations for developing a healthful diet.

In 1980, the U.S. Department of Agriculture and the U.S. Department of Health and Human Services published the first edition of the Dietary Guidelines for Americans (DGA). These 1980 guidelines, published as a 19-page pamphlet, provided Americans with seven focus areas for improving their overall health through nutrition. ¹⁶ One of these focus areas, “Avoid Too Much Fat, Saturated Fat, and Cholesterol,” encouraged Americans to limit their intake of dietary cholesterol in order to reduce their risk of CVD, and provided eggs as an example of a common food that consumers could moderate in their diet to achieve that goal. Recommendations that encouraged Americans to reduce their dietary cholesterol intake, specifically through a reduction in their consumption of eggs, appeared almost universally in the bidecennial DGA reports published by the federal government up to, and including, the report published in 2010. ^17,22 A summary of the dietary recommendations for egg consumption and cholesterol included in each of the Dietary Guidelines reports can be found in Table 1.1.

Table 1.1 Recommendations for egg consumption as a means of regulating dietary cholesterol from the Dietary Guidelines for Americans and its predecessor, the Dietary Goals for the United States

Year	Source	Recommendation
1977	Dietary Goals for the United States	“Decrease consumption of butterfat, eggs and other high cholesterol sources.”
1980	Dietary Guidelines for Americans	“Moderate your use of eggs and organ meats (such as liver).”
1985	Dietary Guidelines for Americans	“Moderate your use of egg yolks and organ meats.”
1990	Dietary Guidelines for Americans	“Moderate the use of egg yolks and organ meats.”
1995	Dietary Guidelines for Americans	“Dietary cholesterol comes from animal sources such as egg yolks, meat (especially organ meats such as liver), poultry, fish, and higher fat milk products. [⋯] Choosing foods with less cholesterol and saturated fat will help lower your blood cholesterol levels.”
2000	Dietary Guidelines for Americans	“Use egg yolks and whole eggs in moderation. Use egg whites and egg substitutes freely when cooking since they contain no cholesterol and little or no fat.”
2005	Dietary Guidelines for Americans	No specific recommendation for eggs.
2010	Dietary Guidelines for Americans	“The major sources of cholesterol in the American diet include eggs and egg mixed dishes (25% of total cholesterol intake) [⋯] Cholesterol intake can be reduced by limiting the consumption of the specific foods that are high in cholesterol.”
2015	Dietary Guidelines for Americans	“More research is needed regarding the dose–response relationship between dietary cholesterol and blood cholesterol levels. Adequate evidence is not available for a quantitative limit for dietary cholesterol specific to the Dietary Guidelines. Dietary cholesterol is found only in animal foods such as egg yolk, dairy products, shellfish, meats, and poultry.”

1.2.3 Dietary Reco...

Table of contents

• Cover
• halftitle
• Series Editor
• Title
• Copyright
• Preface
• Contents
• Chapter 1 Eggs as Part of a Healthy Eating Pattern 1
• Chapter 2 Eggs are a Natural Functional Food 22
• Chapter 3 Egg Consumption for Appetite Control and Body Weight Regulation 40
• Chapter 4 Egg Consumption and Cardiometabolic Health 60
• Chapter 5 Food for Thought – Eggs and Neurocognition 83
• Chapter 6 Egg Protein in Sports Nutrition 102
• Chapter 7 Egg Carotenoids for Eye Health 119
• Chapter 8 Eggs and Bone Health 135
• Chapter 9 Chicken Egg: Wholesome Nutrition Packed with Antioxidants 154
• Chapter 10 Modulation of Inflammation by Egg Components 173
• Chapter 11 Antiviral Properties of Egg Components 198
• Chapter 12 Innate Antimicrobial Proteins and Peptides of Avian Egg 211
• Chapter 13 Bioactive Egg Proteins 223
• Chapter 14 Bioactive Minor Egg Components 259
• Chapter 15 Bioactivities and Mechanisms of Egg Protein-derived Peptides 285
• Chapter 16 Applications of Egg Yolk Antibody (IgY) in Diagnosis Reagents and in Prevention of Diseases 305
• Chapter 17 Advances in the Separation of Functional Egg Proteins – Egg White Proteins 329
• Chapter 18 Advances in the Separation of Functional Egg Proteins – Egg Yolk Proteins 348
• Chapter 19 Value-added Uses of Eggshell and Eggshell Membranes 359