Are Raw Onions More Nutritious Than Cooked Onions?


Q: Are raw onions more nutritious than cooked onions?

A: Haley Hooks, a dietetic intern at Tufts’ Frances Stern Nutrition Center, answers: “Onions are nothing to cry over. These flavorful bulbs are an excellent source of healthful chemicals: vitamin C, flavonoids, antioxidants, and sulfur compounds. Onions are nutrient powerhouses, whether eaten cooked or raw; however, raw onions have higher levels of sulfur compounds.

“Why do we care about sulfur in onions? Onions form sulfur compounds through an enzymatic reaction when cut or crushed. Studies show these sulfur compounds may protect against cancer, help lower blood sugar, and reduce the production of unhealthy cholesterol in the body. These sulfur compounds may also block platelet-clot formation and promote the breakdown of blood clots, which helps to lower the risk for heart disease and stroke. Eat your onions raw for maximum sulfur content, as cooking onions significantly decreases the quantity of the compound. However, these sulfur compounds have a downside. They give the onion its pungent odor and cause you to become teary-eyed when you slice it.

“In addition to sulfur, onions have another healthy trait going for them: The outer layers contain quercetin, an antioxidant that fights harmful free radicals in the body. Scientists believe that lightly cooking onions may actually increase the concentration of this nutrient.

“So what is the bottom line? If you like the taste of raw onions, try adding sliced onion to salads, burgers or sandwiches. If you can’t stomach the pungent taste of raw onions, lightly cooked onions still provide a myriad of health benefits.”


  1. I have a feeling onions have a strong capability of warding off viruses. I think so much more research has to be done with this super food.

  2. My diet for rapid weight loss allows raw but not cooked onion purportedly because cooking caramelizes the onion. I don’t get it; the sugar is there whether raw or cooked.

    • Possibly due to the complexity. A complex carbohydrate uses some energy to break down into a simple carbohydrate, so by cooking you are removing this energy absorbent stage, thus increasing the net energy your body takes from the food (My degree is in marine biology – not nutritional biology – so this is just a hypothesis, but I think a logical one).

  3. I use to cook my onions and garlic in different recipes but I couldn’t taste them. I love the taste of them both. Now I cook everything without them and add them raw when I serve myself. Since I live alone it works out great. I can taste them now.

    • Garlic ingestion causes older people to lose some of their hearing capabilities for a period of about six weeks after consuming it. 30 or so years ago people in high places wanted garlic removed from stores but too many people complained because garlic does more than mess with the hearing, it is also helps kill viruses in the body, whether consuming cooked or raw. Recently, they decided to test this theory to see if garlic is good for a person, or as most of the people who consume it daily already know, if it does indeed cause hearing loss.

      • Garlic is harmful, especially raw. There is a reason that it is used as an animal repellant. All animals even down to insects are repelled by garlic. Only stupid humans eat it. Why? I dont know.

  4. I have cooked with onions all my life and they have been very beneficial to my family’s health. When my kids first moved from home, I warned them, don’t forget to eat your onions at least 3 times a week. Their comments were, don’t worry mom, I will. Well they didn’t and within a month they were having trouble with their skin and we’re catching colds. They were eating lots of fast foods and weren’t cooking for themselves with garlic or onions for their health. I told them, garbage in, garbage out! From then on out they did eat more onions and we’re cooking more for themselves!

  5. i have eaten raw onions since elementary school and would pull them straight out of the garden, wipe off the dirt and eat them. lol… my perspiration smelled like onions. holy cow… this was the 1960s.
    i still eat a mad amount of onions. yum, yum… have always enjoyed that pungent smell…
    But, it didn’t stop cholesterol issues, heart disease and high sugars in my adult life.

  6. I like eating onion sandwiches! You slice raw Visalia sweet onion and put on bread with mayonnaise, salt and pepper. Super Good southern lunch.


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