It's time to stop scorning eggs. These hard-shelled wonders are high in protein and cell-building choline, and low in calories and saturated fat. Plus research shows your morning scramble won't significantly raise cholesterol or contribute to heart disease after all. So which egg is best? This primer will help you decide.

Brown vs. white

Choosing white over brown (or vice versa) boils down to aesthetics. “There's no nutritional difference as long as the feed is the same,” says Hilary Shallo Thesmar, PhD, researcher at the Egg Nutrition Center based in Washington, D.C. “Pigmentation depends on the color and breed of the bird.”

Organic

USDA Organic eggs are produced by hens fed a 100 percent organic diet, containing no hormones or animal by-products. But watch out: Eggs labeled “vegetarian-fed” and “antibiotic-free” aren't necessarily certified organic. And while organic hens must have some access to the outdoors, USDA Organic does not mean birds are raised in cage-free or free-range environments.

Cage free vs. free range

Only 5 percent of the country's 279 million egg-laying hens are allowed to roam “cage free” in the coop rather than being confined to crowded pens. “Free-range” hens have access to the outdoors. But because neither label is regulated, the amount of access birds have to the outdoors varies by producer. Search out cartons with United Egg Producers and American Humane Association logos, which indicate that producers met strict standards that require more cage space and better ventilation.

Omega-3 enriched

Hens fed diets rich in flaxseed and marine algae produce eggs that contain higher levels of omega-3 fatty acids. Omega-3s aren't present in egg whites, though, so you'll have to eat the yolk to get the 1.6 grams recommended daily for adults. Another label — “lutein enhanced” — indicates that hens were fed marigold extract, which contains the eye-essential nutrient.