We all know leafy greens are good for us…but just what the heck are they? Some definitions are so broad as to be meaningless, including everything from lettuce to broccoli.For clarity’s sake, we’ll define leafy greens as those green, leafy vegetables that require cooking to tame their otherwise bitter taste.

So why should you steam, wilt or sautee yourself some greens this spring? Because these leafy lovelies offer a bumper crop of possible health benefits — ranging frommental sharpness to weight management.Like their cruciferous cousins, leafy greens also contain glucosinolates that may activate the body’s own natural defense systems.

If you’re unfamiliar with these hardy greens, check out our nutrient guide on several verdant varieties:

Kale: One of the healthiest greens for your bones, just one cup cooked contains nearly 1,300% of your daily requirement of vitamin K (helps support healthy bone formation).Kale also contains manganese which promotes bone density, vitamin C which supports collagen formation, plus a healthy dose of calcium.Unlike some other produce (e.g.spinach), kale is relatively low in oxalates (which can bind with calcium and prevent its absorption).Bonus: Kale is the top leafy green source of carotenoids which may promote eye health and  lower the risk of age-related macular degeneration.

Collards: While this Southern staple contains three times as much calcium as kale, nearly none of it can be absorbed due to collards’ high oxalate content.Fortunately, collards provide other bone-healthy nutrients: nearly 1,000% of your daily vitamin K needs, and an excellent source of vitamin C and folate.Like kale, collards are loaded with the same eye-healthy carotenoids mentioned above.

Swiss chard: Best greens to possibly lower blood pressure as one cup cooked supplies nearly one-third of your daily potassium requirement.

A mineral marvel, Swiss chard is the top leafy green source of iron, integral to the formation of hemoglobin, a blood protein that carries oxygen from the lungs to the rest of the body.Swiss chard’s excellent source of vitamin C helps enhance absorption of its iron content (making it a must-add to the menu of those 15% of pre-menopausal women who fail to get enough iron).

Chicory: As discussed in the DNN story “Bitter Herbs for Better Health,” chicory rivals collards and Swiss chard in vitamins A, C and K, plus minerals like potassium and copper, and, last but not least, plenty of phytochemicals.Bonus: Chicory contains fructans, carbohydrate components that studies suggest may promote healthy arteries, bones and a healthy GI tract.

Mustard and Turnip Greens: While these two don’t pack quite the nutrient punch of some of the leafies listed above, they still contain large amounts of the bone-healthy vitamins K, C and folate, plus vitamin A carotenoids.They’re also a good plant source of vitamin E, a potent antioxidant that may help boost immunity by shielding immune cells from free-radical damage and supporting production of bacteria busting white blood cells.Bonus: Compared to King Kale, turnip greens are even higher in calcium (and as low in oxalates) making it a top plant source of this mineral.

For a delicious way to get your greens, try this issue’s featured recipe, “Steamed Greens with Ginger and Water Chestnuts” — just one of the many fantastic dishes contained in our current fave cookbook, The New American Plate, published by theAmerican Institute for Cancer Research.