Onions aren’t just flavoring to your favorite dishes. They are low in calories, have virtually no fat and are loaded with healthful components that fight inflammation in arthritis and related conditions.

Onions are also one of the richest sources of flavonoids – antioxidants that mop up free radicals in your body’s cells before they have a chance to cause harm. One flavonoid found in onions, called quercetin, has been shown to inhibit inflammation-causing leukotrienes, prostaglandins and histamines in osteoarthritis (OA) and rheumatoid arthritis (RA), reduce heart disease risk by lowering low-density lipoprotein (LDL) or “bad” cholesterol and help prevent the progression of cancer.

Help for inflamed joints, heart disease and cancer aren’t the only benefits neatly wrapped in an onion's layers. One of its powerful compounds may also give a boost to bones. Known as GPCS for short, gamma-L-glutamyl-trans-S-1-propenyl-L-cysteine sulfoxide was shown to inhibit the breakdown of bone in a study published in the Journal of Agriculture and Food Chemistry. Researchers at the University of Berne, Switzerland, speculate that GPCS might work the same way as alendronate (Fosamax), which is used to treat osteoporosis and reverse corticosteroid-induced bone loss.

Strong Smell = Strong Powers

All onions are healthful, but not equally so, according to a study from Cornell University in Ithaca, N.Y. Disease-fighting chemicals are highest in shallots and yellow and red onions, and lowest in white and sweet onion varieties.

Shallots, and yellow and red onions also have a stronger flavor than white varieties, suggesting the more pungent the onion the more powerful the health-promoting properties, says Rui Hai Liu, MD, PhD, associate professor of food science at Cornell.

5 Ways to Add Onions to Your Meals

Raw or cooked, onions make a healthful addition to any dish. Here are a few suggestions:

Salads. Raw, red onions, sliced or diced, add a healthful and colorful splash to any salad.

Stir-frys. Add strips of yellow onions to a vegetable medley. They cook quickly – in four to five minutes in a stovetop skillet on high heat – and increase your vegetable-rich dish’s antioxidant boost.

Sandwiches. Sweet, white, yellow, red – sauteed or raw – onions on sandwiches are a great idea. Load your sandwiches with lots of onions and other vegetables to help increase your phytochemical intake while decreasing portions of other sandwich ingredients, like meats and cheeses that should be eaten in moderation.

Side Dish. Grill, bake or broil thick slices of onion brushed with a little bit of olive oil to bring out the sweetness.

Saved for Later. Have extra cut, raw onions? Stick them in resealable bags in your freezer and spare yourself more chopping and tears.