Onions May Help Prevent Inflammation

These flavorful veggies are packed with healthy nutrients.

Updated by Linda Rath | March 24, 2023 

Onions aren’t just flavoring for your favorite dishes. They’re also low in calories, have virtually no fat and are loaded with healthful components that may help 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 in animals and cell cultures to inhibit inflammation-causing leukotrienes, prostaglandins and histamines in osteoarthritis (OA) and rheumatoid arthritis (RA), to reduce heart disease risk by lowering low-density lipoprotein (LDL) or “bad” cholesterol, and to 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, the compound has been shown in studies to prevent the breakdown of bone and decrease fracture risk in postmenopausal women. Earlier studies had similar findings in non-Hispanic white women; it’s not clear if this is true for people of other races and ethnicities.

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, a professor of food science at Cornell University.

5 Ways to Add Onions to Your Meals

If you’re following a low FODMAP diet, most members of the onion family are off-limits. Otherwise, raw or cooked onions make a healthful addition to any dish. Here are a few suggestions:
  1. Salads. Raw, red onions, sliced or diced, add a colorful zing to any salad.
  2. 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 sweetness and antioxidant boost.
  3. Sandwiches. Sweet, white, yellow, red — grilled, sauteed or raw — load your sandwiches with onions and other vegetables to increase your phytochemical intake while decreasing portions of other ingredients, like meats and cheeses, that should be eaten in moderation.
  4. Side Dish. Grill, bake or broil onion halves or wedges tossed with olive oil, salt and pepper to bring out the sweetness.
  5. Save for Later. Have extra cut, raw onions? Put them in resealable bags in your freezer to spare yourself more chopping and tears.

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