Potential Health Benefits & Nutritional Facts of Eggs

Potential Health Benefits & Nutritional Facts of Eggs

The humble  egg has impressive health credentials. Nutritionist Jo Lewin shares recipes, nutritional highlights and tips on choosing a good egg.

An introduction to eggs...

Both the white and yolk of an egg are rich in nutrients - proteins, vitamins and minerals with the yolk also containing cholesterol, fat soluble vitamins and essential fatty acids. Eggs are an important and versatile ingredient for cooking, as their particular chemical make up is literally the glue of many important baking reactions.

Since the domestication of the chicken, people have been enjoying and nourishing themselves with eggs. As a long time symbol of fertility and rebirth, the egg has taken its place in religious as well as culinary history. In Christianity, the symbol of the decorated egg has become synonymous with Easter. There are lots of different types of egg available, the most commonly raised are chicken eggs while more gourmet choices include duck, goose and quail eggs.

Nutritional highlights

Eggs are a very good source of inexpensive, high quality protein. More than half the protein of an egg is found in the egg white along with vitamin B2 and lower amounts of fat and cholesterol than the yolk. The whites are rich sources of selenium, vitamin D, B6, B12 and minerals such as zinc, iron and copper. Egg yolks contain more calories and fat. They are the source of cholesterol, fat soluble vitamins A, D, E and K and lecithin - the compound that enables emulsification in recipes such as hollandaise or mayonnaise.

Some brands of egg now contain omega-3 fatty acids, depending on what the chickens have been fed (always check the box). Eggs are regarded a 'complete' source of protein as they contain all eight essential amino acids; the ones we cannot synthesise in our bodies and must obtain from our diet.

One  Large  Egg  Contains:
78 calories	6.3g  protein	5.3g  fat	1.6g saturated fat	212mg cholesterol

The cholesterol question :

For years eggs have been considered more of a health risk than a healthy food. Since they are high in cholesterol, it was recommended that people with high cholesterol levels avoid eggs. But it turns out the cholesterol content for which they have been vilified is much lower than it was 10 years ago. This reduction has been attributed to the changes in hen feed since the BSE crisis in the 1990s. British research shows that a medium egg contains about 100mg of cholesterol, a third of the 300mg recommended daily limit. Also it is saturated fat in the diet, not dietary cholesterol that influences blood cholesterol levels the most.
If you are concerned about your cholesterol or are unsure whether it is safe for you to consume eggs please consult your GP.

Heart healthy...

Eggs are rich in several nutrients that promote heart health such as betaine and choline. During pregnancy and breast feeding, an adequate supply of choline is particularly important, since choline is essential for normal brain development. If you are eating eggs during pregnancy however, ensure you cook until the whites and yolks are solid. In traditional Chinese medicine, eggs are recommended to strengthen the blood and increase energy by enhancing digestive and kidney function.

Eggs also contain more Vitamin D than they did 10 years ago, which helps to protect bones, preventing osteoporosis and rickets. And they are filling too. Eggs for breakfast could help with weight loss as the high protein content makes us feel fuller for longer. Eggs should be included as part of a varied and balanced diet.

Quail eggs...

Quail eggs have a similar flavour to chicken eggs, but their petite size (five quail eggs are usually equal to one large chicken egg) and pretty, speckled shell have made them popular in gourmet cooking. The shells range in colour from dark brown to blue or white. Quail eggs are often hard-boiled and served with sea salt.
 

Duck eggs...

Duck eggs look like chicken eggs but are larger. As with chicken eggs, they are sold in sizes ranging from small to large. Duck eggs have more protein and are richer than chicken eggs, but they also have a higher fat content and more cholesterol. When boiled, the white turns bluish and the yolk turns red-orange.

How to select and store

Choose eggs from free-range or organically raised chickens. Eggs should always be visually inspected before buying. It is best to check for cracks or liquid in the box to ensure there are no broken ones. Eggs are best stored in the refrigerator where they may remain for up to one month (check the best-before-date on the box). Eggs with higher omega-3 fatty acid content are best eaten as early as possible to keep these oils fresh.

Safety:

The main safety concern is risk of salmonella food poisoning. The best protection is to cook eggs at a high enough temperature for a long enough period of time, meaning poached, scrambled and hard boiled eggs carry a much lower salmonella risk. Another safety concern regarding eggs is that they are a common food allergen, particularly among young children. See your GP if you have any concerns regarding allergies to eggs. Substitutes can be used to bind ingredients together but they are not as good at helping mixtures rise. If using a replacement for eggs in baking, adding a little extra baking powder may help.

Top tip... A fresh egg will sink in water, a stale one will float.

Recipe suggestions

Eggs are paramount to a number of classic recipes so here are just a few of our favourites:

Healthy egg and chips - can it be true?
Healthy egg & chips

Boiled egg in a salad - a great lunchtime choice
Warm chorizo, sweet potato & egg salad
Lentil & red pepper salad with a soft egg

Nutritional Facts on Ostrich Eggs

Ostrich eggs are the largest laid by any bird. They measure approximately 6 to 7 inches in length and as much as 18 inches around. Ostrich were first imported to the United States in the 1880s. The breeding industry surged in the 1980s, and as of 2002, there were 1,600 ostrich ranches in the United States providing meat, feathers, hides and eggs to consumers.

Serving Comparisons

No one individual is ever likely to eat an entire egg in one sitting, as one ostrich egg is roughly the equivalent of 24 chicken eggs .

Calories

A serving of ostrich egg equal to one chicken egg contains 83 calories, six more than an average-sized chicken egg. An entire ostrich egg contains approximately 2,000 calories, notes Wellsphere. Both types of eggs are approximately 47 percent protein and 45 percent fat.

Vitamins

According to the Mazuri website, an ostrich egg contains 16.29 IU/g vitamin A, while a chicken egg contains 20.5 IU/g. There is an even greater difference in vitamin E content: 39.95 IU/g in a chicken egg but only 15.31 IU/g in an ostrich egg. However, ostrich eggs are a good source of  Thiamine (Vitamin B1).

Ostrich eggs are proved to be a healthier alternative to chicken eggs. When cooked, these eggs are fluffy in texture and mildly sweet in flavour. Besides their common use in decorations and other artistic creativities, they make for some excellent baking items like, pastries and egg dishes! Time to know some significant health benefits of these dark and patchy eggs:-

1) Though, vitamin and mineral content are almost similar to chicken eggs, they have higher proportion of unsaturated fatty acids.

2) Ostrich eggs serve to be much better heart protector with raised amount of omega-3-fats.

3) These eggs are a way richer in magnesium and iron.

4) Despite being the largest edible egg ( One ostrich egg is equivalent to 24 chicken eggs !), you get only 1/6th the times of calories than chicken eggs.

5) The best part is that you get enough fiber as an added bonus.

One Ostrich Eggs Dish ! {One Ostrich Egg = 25 Chicken Eggs }

Eggs, pasture-raised(Pasturised Eggs)

Shopping for Eggs
Stick with organic	Organic standards help lower risk of contaminated feed and organic eggs usually have higher nutrient quality. However, remember that organic by itself does not guarantee a natural lifestyle for the egg-laying chickens.
Ask for pasture-raised	Go beyond organic by asking for pasture-raised. Don't get sidetracked by the confusing array of labeling terms. You are likely to find phrases like "pasture-raised," "pastured," "free-range" and "cage-free" on egg packaging, but labeling laws allow products to display these terms even if the egg-laying chickens spend little or no time outdoors in a pasture setting. Talk to your grocer or the chicken producer and find out how the chickens were actually raised.
Consider local farms	Organic, pasture-raised eggs may be available from local farms with small flocks and a natural lifestyle for their chickens. Two websites that can help you find small local farms in your area are www.localharvest.org and www.eatwild.com. Both sites are searchable by zip code.

One additional note about egg selection—we frequently get questions about the advisability of raw egg consumption. In our detailed Q & A on this topic, we review the research-based pros and cons of eating raw eggs and we provide you with some practical recommendations in this area.

What's New and Beneficial About Eggs

• Virtually all egg yolks contain omega-3 fats. However, the amount of omega-3s varies with the amount of foods containing omega-3s that are eaten by the hen. In recent years, a marketplace trend has witnessed the development of omega-3 enriched eggs through the addition of omega-3 oils to the hen's feed. These oils have included menhaden oil, krill oil, flaxseed oil, and algae oil. Not surprisingly, the amount of omega-3s in an egg yolk can be increased by three to five times through supplementation of the hen's diet with these oils. Eggs with as much as 250 milligrams of omega-3s per yolk have been produced in this way. While these omega-3 benefits are clearly substantial, what we have been more excited to see in recent research studies is the ability of a hen's natural diet to increase the omega-3s in her eggs. Unlike some approaches to omega-3 enrichment that might involve the addition of processed oils to an already unnatural diet, pasture feeding approaches that offer the hen a generous amount of legumes rich in omega-3s—like clover and alfalfa—make more sense to us. So it's been exciting to see studies that show significantly increased amounts of omega-3s in eggs through natural pasture feeding alone.
• While organizations like the American Heart Association (AHA) allow for regular consumption of eggs in a meal plan, they typically warn that eggs are difficult to include because of their high cholesterol content and potential for increasing risk of heart disease. For persons with health blood cholesterol levels not needing cholesterol-lowering drugs, the AHA recommends a maximum of 300 milligrams of cholesterol per day from food. Since one conventionally produced egg contains about 180-220 milligrams of cholesterol, about two-thirds of the daily limit gets used up by consumption of one egg. Interestingly, several recent large-scale diet studies suggest that the cholesterol content of an egg may be less of a concern in relationship to heart disease than previously thought. In these studies, no increased risk of either heart attack or stroke was shown with intake of one to six eggs per week. (One exception involved participants with type 2 diabetes, whose risk of heart problems was associated with egg intake, even in the range of one to six eggs per week.) Equally interesting was the link between egg intake and increased levels of HDL cholesterol (the "good" cholesterol) in participants. Not only did egg intake increase the number of HDL molecules, it also improved their composition and allowed them to function more effectively.
• Pasture feeding of hens has been shown to significantly increase the vitamin E content of their eggs. In a recent study comparing caged hens to hens foraging on grasses and legumes, vitamin E in the yolk of eggs from hens who foraged on pasture was about 200% greater than vitamin E in the yolk of eggs from caged hens. Interestingly, hens that foraged more on grasses than legumes developed about 25% more vitamin E in their eggs. Hens, of course, are omnivores and eat a wide variety of foods, including grasses, legumes, seeds, worms, grubs (insect larvae), and adult insects.

Eggs, pasture-raised, large, hard boiled 1.00 each (50.00 grams) Calories: 78 GI: low

Nutrient DRI/DV

 Choline :35%     (Choline is a water soluble nutrient that is related to other vitamins, such as folate and those in the B vitamin complex family.)

 Selenium :28%   (Selenium is a mineral found in the soil. Selenium naturally appears in water and some foods. While people only need a very small amount, selenium plays a key role in the metabolism.)

 Biotin :27%  (a vitamin of the B complex, found in egg yolk, liver, and yeast. It is involved in the synthesis of fatty acids and glucose.)

 Vitamin B12 :23%   

 Vitamin B2 :20%

 Molybdenum :19%   (Molybdenum plays a role in a number of important bio-chemical processes, like waste processing in the kidneys, development of the nervous system, and the activation of enzymes that are involved in breaking down food to produce energy.It is also being tested for cancer treatment.)

 Iodine :18%

 Pantothenic acid :14%

 Protein :13%

 Phosphorus :12%

 Vitamin D :11%

 Vitamin A :8%

This chart graphically details the % DV that a serving of Eggs, pasture-raised provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Eggs, pasture-raised can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Eggs, pasture-raised, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

Health Benefits :Broad Nutrient Support

Eggs have long been recognized as a source of high-quality protein. The World Health Organization (WHO) and other public health authorities actually use eggs as their reference standard for evaluating the protein quality in all other foods. Egg protein is usually referred to as "HBV" protein, meaning protein with High Biological Value. Since eggs are used as the reference standard for food protein, they score 100% on the HBV chart. The high quality of egg protein is based on the mixture of amino acids it contains. (Amino acids are the building blocks for making proteins.) Eggs provide a complete range of amino acids, including branched chain amino acids (leucine, isoleucine, valine), sulfur-containing amino acids (methionine, cysteine), lysine, tryptophan, and all other essential amino acids. Their protein is sometimes referred to as a "complete protein" for this reason.

All B vitamins are found in eggs, including vitamins B1, B2, B3, B5, B6, B12, choline, biotin, and folic acid. Choline is a standout among these B vitamins. In fact, eggs rank higher in choline than any of our other WHFoods. In the U.S., an average diet provides about 300 milligrams of choline per day - less than the recommended amount for an adult woman (425 milligrams) or an adult man (550 milligrams). Since one egg provides over 100 milligrams of choline and only 75-80 calories, it provides far more choline for far less calories than most other choline-rich foods.

The mineral content of eggs also deserves special mention here--not because eggs are a rich source of most minerals but because they are a rich source of certain minerals that can sometimes be difficult to obtain from other foods. Eggs are a very good source of both selenium and iodine. While many fish, shellfish, and mushrooms can be rich sources of selenium, persons who avoid these foods may sometimes have difficulty getting an adequate amount of this important antioxidant mineral from food. For persons who do not use iodized salt in recipes or at the table and who do not consume either yogurt or cow's milk, this mineral can also sometimes be challenging to obtain from food.

The nutrients found in an egg are distributed fairly evenly between the yolk and the white. This distribution of nutrients is a common characteristic of whole, natural foods and it is one of the reasons that we recommend consumption of whole eggs (except, of course, when only the yolk or the white is called for in a recipe). The chart below explains what approximate percent of the total nutrient amount is found in the yolk and the white of an egg. You will notice that the first four nutrient groupings are those that are found predominately in the egg white, while those that follow are found predominately in the egg yolk (all except for the last nutrient, selenium, which is divided fairly evenly between the egg white and yolk).

Nutrient	Egg White	Egg Yolk
Protein	60%	40%
Magnesium, Potassium, Sodium	10-25%
Vitamin B3	90%	10%
Vitamin B2	62%	38%
Total Fat	10%	90%
Omega-3 Fats	0%	100%
Vitamins A, D, E, K	0%	100%
Carotenoids	0%	100%
Vitamins B5, B6, B12, Folate, Choline	10% or less	90% or more
Calcium, Phosphorus, Zinc, Copper, Iron	10% or less	90% or more
Manganese	30%	70%
Vitamin B1	25%	75%
Biotin	20%	80%
Selenium	41%	59%

Omega-3 Support

In recent years, there has been a food marketplace trend of greater availability of eggs that are unusually rich in omega-3 fats. These eggs get their high levels of omega-3s through the addition of omega-3 oils to the hen's feed. Oils added to the hen's diet as a way of increasing omega-3s include menhaden oil, krill oil, flaxseed oil, and algae oil. The supplementation of the hen's diet with these oils usually produces as much as 250 milligrams of omega-3s per egg yolk.

What many consumers do not know is that virtually all egg yolks contain omega-3 fats and that by providing hens with a natural, pasture-based diet their omega-3 levels can be naturally increased. Pasture feeding can provide the hen with clover and alfalfa, two examples of legumes that are rich in omega-3s; in fact, pasture feeding can double the amount of omega-3s in an egg yolk. Omega-3s are far too low in the average U.S. diet, and eggs from pasture-raised chickens can provide significant amounts of these anti-inflammatory fats.

Other Health Benefits

As a group, research studies on the health benefits of eggs have shown mixed results. Part of the difficulty that researchers encounter when trying to determine the pros and cons of egg intake is the tendency of participants to consume other foods high in fat and/or saturated fat along with eggs. For example, at breakfast meals in the U.S., eggs are often consumed together with bacon, sausage, or ham. This simultaneous consumption of eggs with other foods can make it difficult for researchers to separate out the specific influence of the eggs. In addition, from a calorie standpoint, two eggs typically provide only 150-175 calories—only 7-8% of a 2,000-calorie diet. This small amount can make it more difficult for researchers to pinpoint the role played by the eggs.

Another complicating factor in egg research is the fiber-free nature of eggs. Since fiber typically has a risk-lowering affect for cardiovascular disease, diabetes, and cancer, egg intake might show up as problematic in a diet that was otherwise very low in fiber, yet helpful in a diet that was otherwise rich in fiber.

These factors described above do not change our view of eggs as an unusually nutrient-rich food that can provide a unique combination of nutrients for a very small number of calories. But they do underscore the importance of integrating eggs into an otherwise healthy meal plan.

In the area of cardiovascular disease, recent studies have shown no increased risk of either heart attack or stroke in conjunction with egg intake of one to six eggs per week. Interestingly, these studies have also shown the ability of egg intake to increase levels of HDL cholesterol (the "good" cholesterol). Not only did egg intake increase the number of HDL molecules, it also improved their composition and allowed them to function more effectively. This improved function may have been the result of more phosphatidylethanolamine being added to the HDL molecules. (The addition of phosphatidylethanolamine, in turn, might have been related to the rich initial choline content of the eggs.)

Not all egg studies show potential cardiovascular benefits, however, and in some studies, egg intake has been related to some increased mortality risk. However, as mentioned previously, it's been difficult for researchers to separate out the possible role of other foods in many studies. Particularly in mortality studies, which often examine diet in very general terms, they are unable to look closely at specific egg amounts in the diet.

One further note about the relationship between egg intake and cardiovascular risk: some persons with type 2 diabetes may be more susceptible to unwanted cardiovascular problems in relationship to egg intake if their type 2 diabetes has also created problems with cholesterol transport through the bloodstream. (These transport problems often correspond to low levels of apolipoprotein E and high levels of apolipoprotein C-III in the blood, which can be determined by lab testing.) Given this connection, persons with type 2 diabetes are encouraged to consult with their healthcare provider when making decisions about eggs in their meal plan.

Like studies on eggs and cardiovascular risk, studies on eggs and cancer risk have been mixed. We have seen large-scale studies in which egg intake was associated with a decreased risk of breast cancer and included along with vegetables, fruits, and legumes as a desirable factor in a risk-lowering meal plan. Yet we have also seen studies in which risk of colon and rectal cancer was increased by egg intake. For us, the mixed nature of these cancer studies underscores the need to consider health benefits of eggs as being conditional upon the overall quality of the diet; we should not be assuming that eggs will automatically lower or raise cancer risk regardless of an overall meal plan.

A Practical Take-Away

We include eggs as one of our WH Foods because of the broad nourishment they provide, their unique combination of nutrients (including omega-3s, antioxidant minerals like selenium, and high biological value protein), and their low calorie cost. Eggs are a nutrient rich, natural, whole food. At the same time, research on eggs has not always shown them to provide health benefits, and in some situations (for example, individuals with type 2 diabetes who are trying to lower their risk of cardiovascular problems) eggs may not be appropriate as part of a routine meal plan. So even though eggs are a natural, nutrient rich whole food, we do not consider them mandatory in any meal plan.

If you do decide to consider the addition of eggs to your meal plan, we encourage you to take a close look at your overall diet. Could it use more protein? If so, eggs might make sense. Does it already have plenty of fiber? If not, it might make more sense to add a fiber-containing food rather than eggs. We're confident that in many diets, pasture-raised eggs can provide key nutrient benefits and lower your disease risk, despite some of the confusion that we've come across in the food science research.

Description

 The eggs laid by female chickens (hens)—belong to the bird class of animals (Aves). Hen's eggs are one among many types of bird eggs enjoyed in diets worldwide. Eggs from ducks, geese, quail, turkeys, and ostriches are also part of many cuisines. Birds (including chickens) are omnivores, which means that they eat both meat and plants. Hens, for example, often enjoy eating insects, insect larvae (grubs), and worms. Some of this intake helps explain the unique combination of nutrients found in eggs.

Chicken eggs are by far the most common type of egg consumed in the U.S., and the breeding of chickens for egg production has resulted in breeds that can lay 200-300 eggs per hen per year. Some of the more popular egg-laying breeds include White Leghorns, Rhode Island Reds, Buff Orpingtons, Golden Coments, Red Sex Links, Isa Browns, Australorps, Black Star, Red Star, Light Sussex, and Plymouth Rock. All of these breeds belong to the same genus, species, and subspecies of animal, namely, Gallus gallus domesticus. You may also hear chickens being referred to as "junglefowl," which is a common name for all animals belonging to the Gallus genus.

The composition of an egg is usually described as having two basic parts: the white and the yolk. The white is approximately 87% water and 13% protein, and contains both vitamins and minerals. The yolk is about 50% water, 33% fat, and 17% protein; like the white, it also contains both vitamins and minerals. Please see our Health Benefits section for a more detailed description of the nutrients found in each part of the egg.

Egg grading standards are based on the clearness, firmness, and thickness of the white, the presence or absence of defects in the yolk (like blood spots or meat spots), the size of the air cell inside of the shell (the smaller this air space, the higher quality the egg), and the cleanness of the shell, including the absence of any slight breakage. Eggs that score highest on these qualities are graded "AA." Fairly close in quality are "A" eggs. The shelf life of an egg is related to its grade, and a fresh AA egg will have a longer shelf life than a fresh A egg. However, an egg's grade is not the same as its freshness. For more information on egg grading and freshness - including our practical recommendations - please see our How to Select and Store section.

The size of an egg is related to its weight. The chart below provides a summary of the standards used to label eggs as small, medium, large, extra large, or jumbo.

	Average weight per egg (in grams)	Average weight per egg (in ounces)
Small	43	1.5
Medium	50	1.75
Large	57	2.0
Extra large	64	2.25
Jumbo	71	2.5

History

As mentioned in our Description section, bird eggs (including chicken eggs) have long held a place in cuisines worldwide. The variety of bird eggs enjoyed in many cultures includes duck, goose, quail, turkey, and ostrich eggs. With respect to their history, it's also worth noting that birds were not the first animals to reproduce by means of shell eggs. Reptiles were the first animals to do that, nearly 150 million years before the first shell eggs produced by birds.

Eggs have always had a primary place in mythologies, religions, and cultural practices worldwide, and have typically been regarded as symbols of rebirth, renewal, beginnings, and fertility. One of the most widely held food and holiday associations is that of the Easter egg. How the egg became associated with this holiday seems to have roots that are both biological and cultural. Before the more modern techniques of poultry raising, hens laid few eggs during the winter. This meant that Easter, occurring with the advent of spring, coincided with the hen's renewed cycle of laying numerous eggs. Additionally, since eggs were traditionally considered a food of luxury, they were forbidden during Lent, so Christians had to wait until Easter to eat them—another reason eggs became associated with this holiday. Interestingly enough, the custom of painting eggshells has an extensive history and was a popular custom among many ancient civilizations, including the Egyptians, Chinese, Greeks, and Persians.

Today, egg production in the U.S. has reached a level of 762 billion eggs per year. About 70% of these eggs are sold and purchased in whole form, and about 30% are removed from shells at "breaker plants" across the country and converted into egg products, including both liquid and dried yolks and whites. Iowa, Ohio, Pennsylvania, Indiana, and California are the country's top five egg-producing states. On a global basis, the U.S. is the largest egg-producing country in the world, followed by Mexico and Brazil. However, small numbers of eggs are produced in most countries worldwide, and out of the world's total (63.7 million tons of hen's eggs), only 20% (12.8 million tons) are produced in all North American, Central American, and South American countries combined.

How to Select and Store

Labeling terms that appear on egg packaging are among the most confusing and misleading for any food type. You might find all of the following terms on the label of an egg carton:

• cage-free
• free-range
• free roaming
• pastured
• pasture-raised
• organic
• omega-3
• omega-3 enriched

Unfortunately, while legal, some of these labeling terms are also misleading. The term "free-range," for example, means that the hens who lay the eggs must have access to the outdoors—but the emphasis here is on "access." No standards are set for how often the hens actually go outside, how much time they must stay outside if they do go out, or what the outdoor environment must include in terms of total space or vegetation. "Pastured" and "pasture-raised" are similarly misleading terms that are not backed up by standards for actual time spent by hens in a pasture setting or standards for qualifying an outdoor space as "pasture." Use of the term "cage-free" on the label of an egg carton means what it says—but legal use of this term does not require hens to have any access to outdoor space and therefore may be used when hens have been confined indoors full-time.

When an egg carton displays the USDA organic logo, you still cannot be certain that chickens have spent much time outdoors. Organic standards for eggs do require outdoor access for hens, but the exact standards for outdoor access are not well defined. For example, no minimal amount of days spent outdoors or time per day spent outdoors is specified. Organic standards require strict feeding with certified organic feed, but legal use of the organic label does not require any fixed amount of feed to be obtained from a pasture setting. These limitations of the organic logo are one more reason that we encourage you to talk with your grocer or egg producer and find out how the chickens were actually raised.

Another confusing aspects of egg selection is deciding about an egg's freshness before you purchase it. Unfortunately, the labeling on an egg carton cannot help you make a clear decision about freshness. An expiration date for the eggs is usually stamped on the side of the carton, often with the abbreviation "EXP" (e.g., EXP Jan23) However, this expiration date is calculated from the time of packaging not from the time when the egg was laid by the hen. (Thirty days is the maximum amount of time allowed between the packing date and the expiration date.) Since you would want to know time from egg laying in order to determine freshness, the expiration date cannot help you here as much as you would like.

As presented in more detail in our Description section, eggs that score highest on certain qualities are graded "AA." Fairly close in quality are "A" eggs. The shelf life of an egg is related to its grade, and a fresh AA egg will have a longer shelf life than a fresh A egg. In and of itself, however, a grade of AA does not tell you that an egg is fresh, since the egg grading system does not take the time of laying into account. If an AA egg is fresh, it will stay fresh longer than an A egg. But this benefit of an AA egg still does not tell us whether an AA egg is fresh in the first place.

Because of these limitations in the grading system and expiration date assignment for eggs, we recommend that you talk either with your grocer (depending on his or her knowledge of the situation) or the farm itself to determine the freshness of your eggs. In some situations, there may only be several days between the laying of an egg and its appearance in the dairy section of your grocery. In other situations, there might be three weeks or more. As we have discussed previously in this profile, another alternative is to purchase eggs directly from a small local farm that sells to consumers.

Although it is possible to detect some aspects of egg safety from visual inspection of an egg and evaluation of its odor, in the key area for egg safety—contamination of an egg with Salmonella enteritidis (SE) bacteria—our sense of sight and smell are of no help whatsoever in determining the likelihood of SE contamination. While SE bacteria are larger than viruses, they are still invisible to the naked eye and cannot be seen without a microscope. The steps used by public health agencies for detecting the presence of SE in eggs or hen houses are complicated and involve complicated lab techniques. Gene typing, antibiotic susceptibility testing, culture methods, and biochemical marker testing are basic methods used to determine the presence of SE. Here are some factors to look for when inspecting an egg, and their relationship to egg safety:

• Cloudiness of egg whites: The white of a fresh egg is naturally cloudy. This cloudiness is mostly due to presence of dissolved carbon dioxide and the suspension of albumen proteins in the watery liquid that forms the white. As an egg ages, carbon dioxide will escape through pores in the shell and the white will may also become less acidic. These changes are typically associated with a clearing of the white and less cloudy appearance. The bottom line: you can generally use the cloudiness of the egg white to help confirm freshness, with cloudy whites indicating fresh eggs. But degree of cloudiness has no relationship to SE contamination. Since we recommend consumption of eggs that are as fresh as possible, we encourage you to look for egg whites that are cloudy in appearance.
• Yolk firmness and color: Yolk color is mostly related to the hen's diet. If the hen eats more pigmented plants (for example, the petals of flowers with orange or yellow pigments or yellow corn), the yolk will typically be darker and richer in color. By contrast, if the hen eats large amounts of white corn in her feed, the yolk will be less colorful. Like the white of an egg, its yolk will undergo changes as it ages. Over time, the yolk membrane will weaken, and the yolk will become flatter. Once again, these features can help you confirm an egg's degree of freshness but they are not related to the presence or absence of SE. We recommend eating eggs from pasture-raised hens, and the yolks of those eggs are more likely to be richer in color from the natural diversity of pasture plants.
• Red blood spots on the yolk: These spots are caused by the breaking of a blood vessel along the surface of the yolk. This type of breakage can occur naturally and is not a sign of contamination. We are not aware of any research showing safety risks from cooked eggs with blood spots.
• Pinkish egg whites: If the egg white has a pinkish color, it is usually a sign of bacterial spoilage, and the bacterium most often involved is Pseudomonas. While other spoilage bacteria like coliform or Flavobacterium can play a role in egg white discoloration, pinkish egg whites are not a sign of SE. You should discard eggs if you find pinkish whites inside.
• Off odors: Many different types of spoilage bacteria will produce off-odors in eggs. These off odors may be sulfur-like, or they might simply just smell "bad." Off odors from an egg cannot be used, however, to help determine the presence or absence of SE. But despite the lack of a relationship between a bad smelling egg and SE, we recommend that you discard all eggs with off odors due to a variety of unwanted qualities.

In summary, most visible characteristics of an egg are related to freshness, the breed of the hen and her genetics, and her diet. None of these characteristics can help you determine the presence or absence of SE. That's why it is so important to find very high-quality small local farms or very high quality larger scale egg producers when trying to minimize your risk of exposure to SE contaminated eggs.

Inspect any eggs that you purchase for breaks or cracks. And of course, take care when packing them in your shopping bag for the trip home as they are very fragile.

Always store eggs in the refrigerator. Although eggs will often be safe to consume after the expiration date on the egg carton, we nevertheless recommend consumption of eggs by the designated expiration date for optimal safety and better freshness. When refrigerating eggs, do not wash them as this can remove their protective coating. Keep them in their original carton or in a covered container so that they do not absorb odors or lose any moisture. Do not store them in the refrigerator door since this exposes them to too much heat each time the refrigerator is opened and closed. Make sure to store them with their pointed end facing downward as this will help to prevent the air chamber, and the yolk, from being displaced.

Tips for Preparing and Cooking

Tips for Preparing Eggs

In order to prevent any possible contamination to a recipe by a spoiled egg, break each egg separately into a small bowl before combining with the other ingredients.

How to Enjoy

A Few Quick Serving Ideas

• Hard-boiled eggs are fun to eat and easy to pack for on-the-go lunches.
• Mix chopped up hard-boiled eggs with fresh lemon juice and olive oil, leeks and dill (and salt and pepper to taste) to make a healthy egg salad.
• Instead of Eggs Benedict, make Eggs "Buenodict." Place a poached egg on top of a whole grain English muffin lined with steamed spinach. Top with salsa or any of your favorite seasonings and enjoy.
• Say olé to the day with a huevos ranchero breakfast. Add chili peppers to scrambled eggs and serve with black beans and corn tortillas.

For some of our favorite recipes, click Recipes.

Individual Concerns :Eggs and Food Allergies

Eggs are among the eight food types considered to be major food allergens in the U.S., requiring identification on food labels. For helpful information about this topic, please see our article, An Overview of Adverse Food Reactions.

Handling of Eggs

Health safety concerns about eggs center on salmonellosis (salmonella-caused food poisoning). Salmonella bacteria from the chicken's intestines may be found even in clean, uncracked eggs. You'll find these issues discussed in detail in our Q & A about raw versus cooked eggs. As a general rule, there is more risk associated with soft cooked and "sunny side up" eggs than eggs that have been hard boiled, scrambled, or poached.

Dishes and utensils used when preparing eggs should be washed in warm water separately from other kitchenware, and hand washing with warm, soapy water is essential after handling eggs. Any surfaces that might have potentially come into contact with raw egg should be washed and can be sanitized with a solution of 1 teaspoon chlorine to 1 quart water.

Risk of  Biotin Deficiency

Raw egg whites contain a glycoprotein called avidin. Avidin has a unique preference for binding together with one particular B vitamin—biotin—and when it does, an avidin-biotin complex is formed that is unable to be absorbed from our digestive tract. As a result, we do not get the biotin nourishment that we would otherwise get from the food. Hen's eggs average about 10 micrograms of biotin. Two micrograms are found in the white (where the avidin glycoprotein is also located), and 8 micrograms are found in the yolk. Since cooking is able to denature the avidin glycoprotein in an egg white, cooking also makes this glycoprotein unable to bind together with biotin in either the white or the yolk and prevent its absorption. The Daily Value (DV) for biotin is 300 micrograms, and since the total amount of biotin in one egg is only 10 micrograms, it would not be logical for a person to depend on his or her egg intake to meet the biotin DV. However, loss of biotin nourishment from an egg could still be prevented through cooking, based on food science research in this area.

Other Controversies

Some animal foods and some plants foods have been the subject of ongoing controversy that extends well beyond the scope of food, nutrient-richness, and personal health. This controversy often involves environmental issues, or issues related to the natural lifestyle of animals or to the native habitat for plants. Eggs has been a topic of ongoing controversy in this regard. Our Controversial Foods Q & A will provide you with more detailed information about these issues.

Nutritional Profile

Our food ranking system also qualified eggs as an excellent source of choline and a very good source of selenium, biotin, vitamin B12, vitamin B2, molybdenum, and iodine. Additionally, they are a good source of vitamin B5, protein, phosphorus, vitamin D, and vitamin A.

For an in-depth nutritional profile click here: Eggs.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, an in-depth nutritional profile for Eggs, pasture-raised is also available. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

Eggs, pasture-raised, large, hard boiled 1.00 each 50.00 grams Calories: 78 GI: low
Nutrient	Amount	DRI/DV (%)	Nutrient Density	World's Healthiest Foods Rating
choline	146.90 mg	35	8.0	excellent
selenium	15.40 mcg	28	6.5	very good
biotin	8.00 mcg	27	6.2	very good
vitamin B12	0.55 mcg	23	5.3	very good
vitamin B2	0.26 mg	20	4.6	very good
molybdenum	8.50 mcg	19	4.4	very good
iodine	27.00 mcg	18	4.2	very good
pantothenic acid	0.70 mg	14	3.3	good
protein	6.29 g	13	2.9	good
phosphorus	86.00 mg	12	2.9	good
vitamin D	43.50 IU	11	2.5	good
vitamin A	74.50 mcg RAE	8	1.9	good

World's Healthiest Foods Rating	Rule
excellent	DRI/DV>=75% OR Density>=7.6 AND DRI/DV>=10%
very good	DRI/DV>=50% OR Density>=3.4 AND DRI/DV>=5%
good	DRI/DV>=25% OR Density>=1.5 AND DRI/DV>=2.5%

In-Depth Nutritional Profile for Eggs, pasture-raised

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