Here are a couple more veggies with health benefits: onions and cucumbers — who knew!

ONIONS

Value: In addition to their health benefits, they add amazing flavor to almost all foods.

Nutrients: Onions belong to the lily family, along with garlic, scallions and leeks. A half-cup offers 10 percent of the recommended daily value of vitamin C, along with potassium, calcium, magnesium, phosphorus and dietary fiber.

Health perks: Onions contain more quercetin than any other common fruit or vegetable. The potent antioxidant has been linked to a reduced risk of heart disease, Alzheimer's, prostatitis and a variety of cancers.

Other phytochemicals in onions are known for their anticancer and antimicrobial properties, and also have inulin, a probiotic fiber that can improve the proportion of good bacteria in the colon. Researchers at University of Wisconsin-Madison found onions also show antiplatelet activity (platelet accumulation is linked to heart disease) and also may protect against gastric ulcers.

Nutrition stats: Serving size: 1/2 cup, chopped (80 g), 32 calories, 0.08 g fat, 7.47 g carbs, 1.4 g dietary fiber, 0.88 g protein.

How to buy: According to chef Aliza Green, author of "Field Guide to Produce," you should look for dry, firm, shiny onions with thin, papery outer skins and tightly closed necks. Avoid onions with sprouts emerging because they will taste bitter.

Examine the sprout end of Italian red onions: It is often sunken, and this is where the first signs of spoilage show. Avoid any onions with soft, deeply sunken tops and any black mold.

How to store: In a loosely woven bag — not plastic — in a cool, dark, dry and well-ventilated area, usually the refrigerator. For longer storage, wrap each onion separately in foil and refrigerate. Do not store onions under the sink or with potatoes, which give off moisture that can cause onions to spoil.

CUCUMBERS

Value: One of the cucumber's greatest values is what it does not have — calories. A half cup of sliced cucumber has less than 10 calories. And the expression "cool as a cucumber"? Because of its water content and strong flesh, it can be as much as 20 degrees cooler inside than outside — and the high water content is a thirst quencher.

Health perks: One 81/4-inch cucumber has about one-third the recommended dose of vitamin K, which the majority of the population fails to get enough of, although it is essential for bone formation and can reduce risk of hip fracture in the elderly. A whole cucumber also has 1.5 grams of fiber, 14 percent of the recommended daily value of vitamin C, as well as lesser amounts of calcium, iron, magnesium, phosphorus, potassium, zinc and copper.

Nutrition stats: Serving size: one cucumber (81/4 inches), 45 calories, 0.33 g fat, 10.93 g carbs, 1.5 g fiber, 1.96 g protein.

How to buy: Green says cucumbers should be well-shaped, firm and deep green. Choose hothouse cucumbers with no soft spots. Unwaxed farmers market and locally grown cucumbers are entirely edible. Those that are waxed last longer but must be peeled.

How to store: In the crisper drawer of the refrigerator for up to one week.

Charles Stuart Platkin is a nutrition and public-health advocate, and author of "Breaking the FAT Pattern" (Plume, 2006). Sign up for the free Diet Detective newsletter at www.dietdetective.com.