Thanks to its high cholesterol content, the egg was once deemed villainous. Years went by while many of us shunned eggs, ate only the whites, or ventured into the world of egg substitutes.

Then, in 2000, the American Heart Association (AHA) revised its dietary guidelines and gave healthy adults the green light to enjoy eggs once again. The AHA's guidelines now allow an egg a day for healthy adults while still advising a total daily cholesterol limit of 300 mg.  The confusion over eggs stems from their cholesterol content. One large egg contains 213 mg of cholesterol, accounting for two-thirds of the recommended daily limit. When scientists learned that high blood cholesterol was associated with heart disease, foods high in cholesterol logically became suspect.

But after 25 years of study, it has become evident that cholesterol in food is not the culprit -- saturated fat has a much bigger effect on blood cholesterol. Full-fat dairy products and fatty meats are examples of foods that are loaded with saturated fat and which trigger the body to produce cholesterol. With science on our side, we can once again enjoy the wonderfully nutritious egg. Along with milk, eggs contain the highest biological value (or gold standard) for protein. One egg has only 75 calories but 7 grams of high-quality protein, 5 grams of fat, and 1.6 grams of saturated fat, along with iron, vitamins, minerals, and carotenoids.

The egg is a powerhouse of disease-fighting nutrients like lutein and zeaxanthin. These carotenoids may reduce the risk of age-related macular degeneration, the leading cause of blindness in older adults. And brain development and memory may be enhanced by the choline content of eggs.

WebMD By Kathleen M. Zelman, MPH, RD, LDBy Kathleen M. Zelman, MPH, RD, LD