The incredible and edible egg is available year round to provide not only delicious meals on their own but an essential ingredient for the many baked goods and sauces that would never be the same without them.

Composed of a yellow yolk and translucent white surrounded by a protective shell, the incredible nature of the egg is partially found in their unique food chemistry which allows them help in coagulation, foaming, emulsification and browning.

Eggs are a good source of low-cost high-quality protein, providing 5.5 grams of protein (11.1% of the daily value for protein) in one egg for a caloric cost of only 68 calories. The structure of humans and animals is built on protein. We rely on animal and vegetable protein for our supply of amino acids, and then our bodies rearrange the nitrogen to create the pattern of amino acids we require.

Another health benefit of eggs is their contribution to the diet as a source of choline. Although our bodies can produce some choline, we cannot make enough to make up for an inadequate supply in our diets, and choline deficiency can also cause deficiency of another B vitamin critically important for health, folic acid.

Researchers at the U.S. Department of Agriculture conducted a study to see what would happen if human subjects received a diet low in choline and folate. Male and female volunteers ate low-choline, low-folate meals that provided as little as 13% of the recommended daily allowance of folate. No severe choline or folate deficiencies occurred during the study, but blood levels of choline decreased an average of 25–28% in men and women during the low-choline, low-folate regimes. Levels returned to at least normal when researchers provided more of these important B vitamins to the people in the tests.

Choline is definitely a nutrient needed in good supply for good health. Choline is a key component of many fat-containing structures in cell membranes, whose flexibility and integrity depend on adequate supplies of choline. Two fat-like molecules in the brain, phosphatidylcholine and sphingomyelin, account for an unusually high percentage of the brain's total mass, so choline is particularly important for brain function and health.

In addition, choline is a highly important molecule in a cellular process called methylation. Many important chemical events in the body are made possible by methylation, in which methyl groups are transferred from one place to another. For example, genes in the body can be switched on or turned off in this way, and cells use methylation to send messages back and forth. Choline, which contains three methyl groups, is highly active in this process.

Choline is also a key component of acetylcholine. A neurotrasmitter that carries messages from and to nerves, acetylcholine is the body's primary chemical means of sending messages between nerves and muscles.

One large egg provides 300 micrograms of choline (all in the yolk), and also contains 315 milligrams (yes, milligrams not micrograms) of phosphatidylcholine. Although most sources just report the free choline at 300 micrograms, it is the phosphatidylcholine that is the most common form in which choline is incorporated into cell membrane phospholipids.

In addition to its significant effects on brain function and the nervous system, choline also has an impact on cardiovascular health since it is one of the B vitamins that helps convert homocysteine, a molecule that can damage blood vessels, into other benign substances. Eggs are also a good source of vitamin B12, another B vitamin that is of major importance in the process of converting homocysteine into safe molecules. Eggs are high in cholesterol, and health experts in the past counseled people to therefore avoid this food. (All of the cholesterol in the egg is in the yolk.) However, nutrition experts have now determined people on a low-fat diet can eat one or two eggs a day without measurable changes in their blood cholesterol levels. This information is supported by a statistical analysis of 224 dietary studies carried out over the past 25 years that investigated the relationship between diet and blood cholesterol levels in over 8,000 subjects. What investigators in this study found was that saturated fat in the diet, not dietary cholesterol, is what influences blood cholesterol levels the most.

Improve Your Cholesterol Profile

Not only have studies shown that eggs do not significantly affect cholesterol levels in most individuals, but the latest research suggests that eating whole eggs may actually result in significant improvement in one's blood lipids (cholesterol) profile—even in persons whose cholesterol levels rise when eating cholesterol-rich foods.

In northern Mexico, an area in which the diet contains a high amount of fat because of its reliance on low-cost meat products and tortillas made with hydrogenated oils, coronary artery disease is common. In a study published in the October 2004 issue of the American Journal of Clinical Nutrition, researchers evaluated the effects of daily consumption of whole eggs on the ratio of LDL (bad) cholesterol to HDL (good) cholesterol, and phenotype (the way an individual's genetic possibilities are actually expressed) in 54 children (8-12 years old) from this region. A month of eating 2 eggs daily, not only did not worsen the children's ratio of LDL:HDL, which remained the same, but the size of their LDL cholesterol increased—a very beneficial change since larger LDL is much less atherogenic (likely to promote atherosclerosis) than the smaller LDL subfractions. Among children who originally had the high risk LDL phenotype B, 15% shifted to the low-risk LDL phenotype A after just one month of eating whole eggs.

Helping to Prevent Blood Clots

Eating eggs may help lower risk of a heart attack or stroke by helping to prevent blood clots. A study published in the October 2003 issue of Biological and Pharmaceutical Bulletin demonstrated that proteins in egg yolk are not only potent inhibitors of human platelet aggregation, but also prolong the time it takes for fibrinogen, a protein present in blood, to be converted into fibrin. Fibrin serves as the scaffolding upon which clumps of platelets along with red and white blood cells are deposited to form a blood clot. These anti-clotting egg yolk proteins inhibit clot formation in a dose-dependent manner—the more egg yolks eaten, the more clot preventing action.(December 30, 2003)

Protection against Age-Related Macular Degeneration and Cataracts

Lutein, a carotenoid thought to help prevent age-related macular degeneration and cataracts, may be found in even higher amounts in eggs than in green vegetables such as spinach, which have been considered its major dietary sources, as well as in supplements. Research presented at the annual American Dietetic Association Conference in San Antonio, Texas, October 26, 2003, by Elizabeth Johnson from the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University also showed that natural lutein esters found in eggs are as or even more bioavailable as the forms of the nutrient offered in purified lutein products. Johnson’s trial tested serum lutein concentration in 10 healthy men, before and after daily consumption of 6mg lutein obtained from four different sources : eggs from chickens fed marigold petals (which are high in lutein), spinach (one of the best known sources of dietary lutein), lutein ester supplements (purified lutein) and lutein supplements. Differences in serum lutein levels in response to the various types of doses were observed the day after the first dose: the serum lutein response to egg was significantly greater than the supplements but no higher than the response to the spinach. After nine days of daily lutein dosing, the serum lutein response was significantly greater in the egg phase than either of the supplements or the spinach. The bottom line: this study suggests that eating lutein-rich foods may be a more effective means of boosting lutein concentration in the eye than taking supplements.

Additional research, another human study published in the August 2004 issue of the Journal of Nutrition, confirms that lutein is best absorbed from egg yolk—not lutein supplements or even spinach. Egg yolks, although they contain significantly less lutein than spinach, are a much more bioavailable source whose consumption increases lutein concentrations in the blood many-fold higher than spinach.

Although the mechanism by which egg yolk increases lutein bioavailability is not yet known, it is likely due to the fats (cholesterol and choline) found in egg yolk. Lutein, like other carotenoids, is fat-soluble, so cannot be absorbed unless fat is also present. To maximally boost your lutein absorption, we suggest combining both eggs and spinach. Whether you prefer your spinach steamed, sautéed or fresh in spinach salad, dress it with a little olive oil and a topping of chopped hard-boiled egg. For a flavorful, quick and easy recipe featuring eggs and spinach, try our Poached Eggs over Spinach and Mushrooms.

Protection against the Food-Borne Pathogen, E. coli

Yet another reason to enjoy eggs: a peptide (protein building block) found in egg white binds to the food-borne pathogen, E. coli O157:H7, thus preventing infection, according to Japanese research published in the September 2004 issue of the Journal of Agriculture and Food Chemistry. Egg white's ability to protect against E. coli O157:H7 is especially welcome since drug resistant strains of this (and other) bacteria have arisen from the overuse of antibiotics. The protein, hen egg ovomucin, was tested against a variety of food borne pathogens and was found to bind exclusively to E. coli O157:H7, so the food industry will also be able to use it to detect the dangerous bacterium in foods.

Recent Study Shows Protection against Breast Cancer

Breast cancer incidence rates more than double in Chinese women as they migrate from China to Hong Kong to the United States, and several dietary factors, which differ between the United States and the Chinese population, including intake of soy, meat, and fruits and vegetables, have been suggested to affect breast cancer risk.

A study of 378 women with breast cancer and 1,070 age-matched controls, which was published in the January 2005 issue of Cancer Epidemiology, Biomarkers & Prevention, found two dietary choices that were strongly protective against the disease:

Women consuming the most fruit and vegetables—3.8 or more servings each day—had a 52% lower risk of breast cancer compared to women eating 2.3 or fewer servings of fruits and vegetables daily. Eating eggs—at least 6 eggs a week—was also highly protective, lowering risk of breast cancer by 44% compared to women consuming only 2 eggs a week.

Our food ranking system also qualified eggs as an excellent source of vitamin K, a very good source of selenium, iodine, and vitamin B2 and a good source of protein, molybdenum, phosphorous, vitamin B5 and vitamin D.

Description

Eggs are egg-ceptional foods. They are whole foods, prepackaged sources of carbohydrates, protein, fat and micronutrients. Yet, their eggs-quisite nutritional value should not be surprising when you remember that an egg contains everything needed for the nourishment of a developing chick.

Eggs are composed of a yellow yolk and translucent white surrounded by a protective shell that can be white or brown, depending upon the breed of the chicken. The shell’s color is not related to the quality or nutritional value of the egg itself.

In addition to their wonderful taste and nutritional content, eggs hold an esteemed place in cooking since due to their food chemistry, they serve many unique functions in recipes, including coagulation, foaming, emulsification and browning.

In Latin, the scientific name for chicken is Gallus domesticus.

History

The history of the egg as food runs mostly parallel with the history of people consuming chicken as food. Although it is uncertain when and where it began, the practice of raising chickens for food is ancient and so, subsequently, is the consumption of eggs as food, extending back to the times of early man.

Eggs have always been a symbol of fertility and have been an icon of religious worship. To this day, there is still a lot of folklore surrounding eggs that is enjoyed by different cultures around the world.

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 more modern techniques of poultry raising, hens laid few eggs during the winter. This meant that Easter, occuring 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.

How to Select and Store

Oftentimes, eggs are classified according to the USDA grading system and bear a label of AA, A, or B. This grading is an indicator of quality parameters, including freshness, with AA being of the most superior in quality. Eggs are also labeled according to their size – extra large, large, medium and small – which is graded according to a standard.

Yet, you may not see any labeling on the eggs you buy since it is not legally mandatory that they be inspected and graded by these federal standards. This is often the situation when you buy farm fresh eggs from a local purveyor. If this is the case, get to know the seller and his or her reputation and make sure that, as usual, the eggs are kept refrigerated.

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.

Store eggs in the refrigerator where they will stay fresh for about one month. 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.

How to Enjoy

For some of our favorite recipes, click Recipes.

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.

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.

Safety - Allergic Reactions to Eggs

Although allergic reactions can occur to virtually any food, research studies on food allergy consistently report more problems with some foods than with others. Common symptoms associated with an allergic reaction to food include: chronic gastrointestinal disturbances; frequent infections, e.g. ear infections, bladder infections, bed-wetting; asthma, sinusitis; eczema, skin rash, acne, hives; bursitis, joint pain; fatigue, headache, migraine; hyperactivity, depression, insomnia.

Individuals who suspect food allergy to be an underlying factor in their health problems may want to avoid commonly allergenic foods. Eggs are one of the foods most commonly associated with allergic reactions. Other foods commonly associated with allergic reactions include: cow's milk, wheat, soy, shrimp, oranges, chicken, strawberries, tomato, spinach, peanuts, pork, corn and beef. These foods do not need to be eaten in their pure, isolated form in order to trigger an adverse reaction. For example, yogurt made from cow’s milk is also a common allergenic food, even though the cow’s milk has been processed and fermented in order to make the yogurt. Ice cream made from cow’s milk would be an equally good example.

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. Formerly, these bacteria were found only in eggs with cracked shells. Safe food techniques, like washing the eggs before cracking them, may not protect you from infection. To destroy the bacteria, eggs must be cooked at high enough temperatures for a sufficient length of time to destroy the bacteria. Soft-cooked, sunny-side up or raw eggs carry salmonellosis risk. Hard-boiled, scrambled, or poached eggs do not.

Another reason to avoid consuming raw eggs is that raw egg whites contain a glycoprotein called avidin, which binds to eggs' supply of the B vitamin biotin very tightly, preventing its absorption. Cooking the egg whites changes avidin, making it susceptible to digestion and unable to interfere with the intestinal absorption of biotin.

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 which 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.

References

Ballesteros MN, Cabrera RM, Saucedo Mdel S, Fernandez ML. Dietary cholesterol does not increase biomarkers for chronic disease in a pediatric population from northern Mexico. Am J Clin Nutr. 2004 Oct;80(4):855-61. .
Blumberg J, Johnson E. Lutein and disease prevention. Papers presented at the annual American Dietetic Association Conference, San Antonio, TX, October 26, 2003 and at the First International Scientific Symposium On Eggs and Human Health: The Transition from Restrictions to Recommendations, USDA, Washington, DC, September 23.
Cho HJ, Ham HS, Lee DS, Park HJ. Effects of proteins from hen egg yolk on human platelet aggregation and blood coagulation. Biol Pharm Bull. 2003 Oct;26(10):1388-92.
Chung HY, Rasmussen HM, Johnson EJ. Lutein bioavailability is higher from lutein-enriched eggs than from supplements and spinach in men. J Nutr. 2004 Aug;134(8):1887-93.
Ensminger AH, Esminger M. K. J. e. al. Food for Health: A Nutrition Encyclopedia. Clovis, California: Pegus Press; 1986.
Howell WH, McNamara DJ, Tosca MA, et al. Plasma lipid and lipoprotein responses to dietary fat and cholesterol: a meta-analysis. Am J Clin Nutr 1997 Jun;65(6):1747-64.
Jacob RA, Jenden DJ, Allman-Farinelli MA, Swendseid ME. Folate nutriture alters choline status of women and men fed low choline diets. J Nutr 1999 Mar;129(3):712-7.
Kobayashi K, Hattori M, Hara-Kudo Y, Okubo T, Yamamoto S, Takita T, Sugita-Konishi Y. Glycopeptide derived from hen egg ovomucin has the ability to bind enterohemorrhagic Escherichia coli O157:H7. J Agric Food Chem. 2004 Sep 8;52(18):5740-6.
Margen S and the Editor, Univ of California at Berkley Wellness Letter. The Wellness Encyclopedia of food and nutrition. New York: Health Letter Associates 1992.
Morris MC, Evans DA, Bienias JL, Scherr PA, Tangney CC, Hebert LE, Bennett DA, Wilson RS, Aggarwal N. Dietary niacin and the risk of incident Alzheimer's disease and of cognitive decline. J Neurol Neurosurg Psychiatry. 2004 Aug;75(8):1093-9.
Shannon J, Ray R, Wu C, Nelson Z, Gao DL, Li W, Hu W, Lampe J, Horner N, Satia J, Patterson R, Fitzgibbons D, Porter P, Thomas D. Food and botanical groupings and risk of breast cancer: a case-control study in Shanghai, China. Cancer Epidemiol Biomarkers Prev. 2005 Jan;14(1):81-90.
Wood, Rebecca. The Whole Foods Encyclopedia. New York, NY: Prentice-Hall Press; 1988.