Unfortunately, the onion gets a bad rap in many homes. Sure — you may use them as flavor-enhancers in some of your favorite dishes. But when most of us try to “eat healthy,” onions don’t automatically jump to the top of the shopping list. And that’s too bad…because onions are one of the healthiest foods on the planet.

They’ve been used medicinally for centuries to treat everything from constipation to hair loss. Today, we know that onions have powerful anti-inflammatory properties. In fact, in many parts of the world, onions are used topically to reduce the swelling from bee stings, blisters, and boils.

Scientists now know that onions are also a great source of flavonoids. Why are flavonoids important? Well, basically these phytochemicals (chemicals found in plants) are like the “Green Berets” of antioxidants. They seek and destroy toxins and cancer cells in the body like nobody’s business.

In fact, in 2004, researchers from Cornell University found that when you inject onion extract into cancer cells, the cancer cells stop multiplying.

Researchers measured the flavonoid levels of 10 different types of onions. They found that Western Yellow onions had highest flavonoid content. Shallots had the highest phenolic content (another type of phytochemical).

The researchers injected colon and liver cancer cells with extracts from the different onions. According to the University’s press release “The pungent yellow and Western Yellow onion extracts provided the strongest anti-proliferation against colon cancer cells. The Western Yellow, shallot, and pungent yellow extracts provided the strongest anti-proliferation protection against liver cancer cells.”

The team’s lead researcher went on to say, “Our study of 10 onion varieties and shallots clearly shows that onions and shallots have potent antioxidant and antiproliferation activities and that the more total phenolic and flavonoid content an onion has, the stronger its antioxidant activity and protective effect.”

No doubt about it, the Cornell folks got great results in the lab using onion extract to stop dividing cancer cells.

But what about in real life? Does eating more onions translate into cancer prevention? That’s what researchers set out to discover in the latest study published in the British Journal of Nutrition.

Scientists designed a case-control study with 264 patients with confirmed colorectal cancer and 408 healthy, cancer-free controls. They found that patients with the highest intakes of quercetin, the flavonoid found in onions, significantly reduced their risk of developing colon cancer. In fact, those with the highest intakes reduced their risk by up to 40 percent!

Well, what do you know! One of the world’s oldest (and most pungent) vegetables might also be one of the most beneficial.

Overall, these studies just scratch the surface. More research is needed to fully uncover the role onions play in preventing cancer. I’ll keep you posted as I run across more evidence exploring the benefits of these vegetables.

In the meantime, go ahead and throw caution to the wind! Add onions to your salads, sandwiches, and stir-fries. Choose shallots and Western Yellows, for the most antioxidant punch. And if you’re worried about bad breath, just chew on a little fresh parsley following your meal. That should do the trick quite nicely. I keep a fresh parsley plant in my kitchen window for just such occasions!

Until next time,

Allan Spreen, M.D.
NorthStar Nutritionals