To Your Health

A. Beginning in the 1970s, the American Heart Association began recommending that people restrict their cholesterol intake to less than 300 milligrams per day. Egg consumption, with more than 200 milligrams of cholesterol in one egg, was hit hard by this advice. After 30 years of scorn, eggs are now getting their revenge. It turns out that not only are eggs virtually free from blame with regard to heart disease risk but eggs protect your eyes from macular degeneration, a dreaded irreversible deterioration of the retina and a leading cause of blindness in people over age 65. Egg yolk is rich in lutein and zeaxanthin, two nutrients that protect the retina from damage by the kind of light that can produce macular degeneration.

As for the concern that eggs raise the risk of heart disease, a recent study that involved more than 100,000 nurses and other health care professionals during a period of 14 years found no difference in the heart disease risk for people who consumed less than one egg a week and those who consumed more than one egg a day. It turns out that for about 70% of the population, dietary cholesterol has hardly any effect on serum cholesterol. For the 30% that are affected by dietary cholesterol, it raises both LDL and HDL (the "bad" and "good") forms of cholesterol, so the all-important ratio between the two remains stable.

The nutrient content of eggs is excellent, making it the standard by which other single foods are measured. From only 75 calories, 3% of what most Americans consume daily, a single egg can provide 4-8% of the RDA for a number of vitamins, and egg protein is second only to breast milk in biological value. In the laboratory of Dr. Roger J. Williams, rats fed eggs alone fared better than those fed any other single food. However, if for no other reason than to reduce the likelihood of developing an intolerance or allergy to egg, we should eat a variety of foods.

Egg color (brown, white, or even green) does not seem to affect nutrient content, nor does fertility. Yard eggs are about 10% more nourishing than cage eggs, probably because the hen has the opportunity to add bugs, worms, and leafy greens to the "layer mash" the farmer is giving them, in addition to exposure to sunshine and fresh air. Producing yard eggs is more labor-intensive than cage eggs, so you will pay a premium for them, though most agree that the taste as well as the increased nutrient content make these eggs worth the extra cost. Egg substitutes are still popular with some people, but you should be aware that, except in protein quality, these are no comparison nutritionally to whole eggs. Most egg substitutes are simply colored egg whites, containing almost none of the essential fatty acids, vitamins, minerals, and, perhaps more importantly, none of the taste of whole eggs.

If refrigerated, eggs will be usable for about a month past the time purchased. If you are unsure of the freshness of an egg, put it in a bowl of water. A fresh egg will sink. The older an egg is the more it tends to float. Also, the white of a fresh egg looks cloudier than the white of an older egg.