Few foods are as hotly contested for their nutritional merits as the egg. Nutrition experts have been flummoxed as to whether this is a food to endorse or discredit. When Americans began to be cholesterol-conscious, the egg was one of the first foods they stopped eating. Consumption of fresh eggs dropped 22 percent between 1980 and 1990.
In more recent years, with awareness that saturated fat—and not dietary cholesterol—is the primary cause of high cholesterol in people, consumption of eggs has been steadily increasing. In 2015, annual consumption of eggs in the United States reached 253 per capita, still shy of the 400 eggs a year Americans ate in 1945.
The yolk of an egg contains about 200 mg of dietary cholesterol. Studies show that eating one egg a day does not increase blood cholesterol levels in most people. Nor does it increase the risk of heart disease in healthy people. However, people who have high cholesterol or heart disease generally are encouraged to limit dietary cholesterol. If you have problems with your cholesterol or have type 2 diabetes, ask your doctor how many eggs you can eat.
The yolk of the egg contains all of the fat and cholesterol, as well as the major concentration of calories, B vitamins, and minerals. Eating egg whites deprives you of these nutrients but still allows you to take advantage of eggs' protein and culinary usefulness.
Along with certain kinds of fish such as salmon, mackerel, and sardines, egg yolks are one of the few foods that naturally contain vitamin D. About 7 percent of the RDA for vitamin D can be found in one large yolk. Egg yolks also contain vitamin A and other carotenoids.
For a full list of nutrients, see Eggs in the National Nutrient Database.
Types of eggs
The egg department in the supermarket has become increasingly elaborate. Once you could make a simple choice: White eggs or brown eggs. Today you can choose between many types of eggs, partly based on your politics and partly based on nutrition.
Most white eggs come from the Single Comb White Leghorn breed of hen. Brown eggs are produced by Rhode Island Red, New Hampshire, and Plymouth Rock hens. The color of the shell—and, for that matter, the color of the yolk—has no bearing on the egg’s quality or nutritional value.
In addition to the color of egg shell, you can choose eggs from hens that are free-range, cage-free, certified organic, Animal Welfare Approved, or Certified Humane, or any number of other claims and certifications. (A full list is available in our article How to Buy Eggs.)
Eggs enriched with omega-3 fatty acids are also on the market. The eggs are the same as traditional eggs, except for their enhanced levels of omega-3s, which are polyunsaturated fats that may lower the risk of cardiovascular disease. To produce omega-3-rich eggs, hens are fed a diet with higher levels of omega-3 fatty acids than traditional feed.
Duck, goose, or quail eggs are also available at some gourmet shops and local farms.
Do some research about egg standards and decide for yourself what to look for when you purchase your dozen.
Eggs: Cooking Tips and Recipe Ideas
Eggs are a breakfast and baking staple in most kitchens, and increasingly eaten in savory frittatas or other dishes for dinner.
How to choose the best eggs
USDA egg grades—AA, A, and B—indicate freshness as well as other aspects of quality. Federal grading is not mandatory, but most eggs sold in the United States are inspected by the USDA, marked with that agency’s seal, and assigned a grade. Most eggs that are assigned Grade B end up in egg products and are not sold fresh. Eggs that do not bear the USDA grade seal must be Grade B or better.
Grading is based on the condition of the inside and outside of the egg. Inspectors look at the cleanliness, soundness, shape, and texture of the shell, the thickness and clarity of the egg white, the size and shape of the yolk, the presence of blood spots, and the size of the air pocket in the egg.
The interior of the egg is evaluated by one of two methods: candling and breakout.
- Candling, or rotating the eggs over a high-intensity light, shows the size of the air cell and the condition of the yolk. This process was originally performed with candles, hence its name.
- The breakout method is precisely what it sounds like—breaking a random sample of eggs and evaluating them visually and with special measuring devices.
USDA-graded eggs are also washed with a disinfectant to remove bacteria such as Salmonella, and then sprayed with oil to replace the natural protective coating that is washed away.
Almost all the eggs you’ll find in the supermarket will be graded AA or A, and the two are very nearly comparable. Eggs are also sorted by weight when they are graded, and packed as Peewee, Small, Medium, Large, Extra Large, or Jumbo. There is a difference in weight of 3 ounces per dozen between each size and the next. Medium eggs are appropriate for many cooking uses, but baking recipes, which tend to be more specific in their requirements, often call for large eggs.
Published June 24, 2016