What's in an Egg?
- One large egg contains 6 grams of high-quality protein (in both the yolk and the white). The yolk is also a source of zinc, B vitamins (including riboflavin and folate), vitamin A, iron, and other nutrients.
- In addition to lutein and zeaxanthin, egg yolks provide choline, an essential nutrient, which is especially important for fetal brain development. Researchers have also identified other compounds in eggs that may have anti-cancer, anti-hypertensive, immune-boosting and antioxidant properties.
- "Designer" eggs, from chickens fed special diets, usually contain more lutein, vitamin E and/or heart-healthy omega-3 fats. But they rarely provide enough extra nutrients to be worth their higher cost. Eggs that claim to be rich in omega-3s, for example, contain only a small amount compared to fatty fish, such as salmon.
- Brown eggs are not more nutritious than white. Different breeds simply lay eggs with different shell colors--even blue and green. Yolk color depends on what the chicken ate: wheat and barley produce a light yolk, corn a medium-yellow yolk, and marigold petals a deep yellow. Though not a sure indication, darker yellow yolks may have more omega-3s and carotenoids. Organic eggs, from chickens fed an organic diet, do not have more nutrients than conventionally produced eggs, though some people may prefer them as a way to support organic production.
Words to the wise: Eggs are good food. Most people can eat one or two a day. Just don't mess them up by preparing them with fatty, salty ingredients or serving them with unhealthy side dishes.
Rethinking cholesterol advice
The American Heart Association (AHA) has no specific limit on how many eggs you can eat, as long as you limit your total cholesterol consumption to 300 milligrams a day, on average (200 milligrams if you have heart disease, high cholesterol, or other coronary risk factors). Many researchers believe that the AHA guidelines are too restrictive, however, and endorse a higher daily upper limit for cholesterol for healthy people. A more reasonable goal is 500 milligrams a day (but still 200 milligrams if you have risk factors for heart disease, including diabetes). That would allow for an egg a day--even two on some days--and still leave room for other sources of cholesterol. Other countries, including Canada, the U.K., and Australia, don't set any recommended upper limits for cholesterol, citing a lack of evidence that dietary cholesterol has a major impact on blood cholesterol.
Keep in mind that even if it's okay for most people to consume more cholesterol than previously advised, this does not change recommendations to limit saturated and trans fats (from partially hydrogenated oils), as these fats affect blood cholesterol levels more than the cholesterol you eat does. Only a few foods--notably eggs, shrimp and squid--are very high in cholesterol anyway--and they are low in saturated fat. The biggest problem with meat and dairy foods is not their cholesterol, but their high saturated fat content, which is why you should choose lean cuts and low-fat varieties.