They are a staple in just about every American kitchen – and they do more than just flavor your food.

We’re talking about onions, of course.

Dr. Manny Alvarez, senior managing health editor of FoxNews.com, received this question from a viewer:

My husband told me that he read something about onions being a superfood. Is that true?

Alvarez said this is one instance where you should be saying, “Yes, dear” – because your husband is right.

Onions actually offer superior health benefits to some of our favorite superfoods, like pomegranates, green tea and red wine, he added.

Alvarez checked in with Chris Kilham, the Medicine Hunter, for a second opinion.

“Onions are especially high in beneficial antioxidants including the super-antioxidant, quercetin, which is useful for the heart, for the immune system (and) for many, many things in the body,” Kilham said. “I would make the claim that onions are among the healthiest of all foods you could possibly eat, and that if you eat an onion every day – and I’m not talking raw, you can cook it, prepare it any way you like – you will do far more for your health than eating lots of the super fruits that are available.”

So remember – an onion a day may keep the doctor away.  If you have a question for Dr. Manny Alvarez, email him at Dr. Manny@foxnews.com

How to grow onions in your home garden:

Onion is a very popular vegetable around the world and there are many varieties as well.  Onions are very easy to grow and are a wonderful addition to your garden.

You can grow onions from seeds, seedlings, or sets (small bulblets).   If you are going to use seeds, begin to grow them inside 4-6 weeks before your last frost and then transplant them into you garden.  If you purchase seedlings you can plant them in your garden after your last frost of the season.  Sets are probably the best choice for those who are not familiar with growing onions.  They tend to be easier to grow and also produce larger onion bulbs.

The first thing you’ll need to do is to prepare your soil.  Dig and mix up the top 6 inches of your soil to allow for good drainage.  Add compost and mix well.  Add fertilizer a couple of weeks before you plan to sow your onion sets as this will offer additional nutrients for you soil.  Don’t add more fertilizer after you’ve planted as onions don’t like a lot of nitrogen.

When you are ready to sow your onion sets, dig a shallow hole and insert your sets about 1-2 inches deep.  Fill back up with soil up to the neck.  For seedlings, place them just below the surface and pack your soil around it.  You can sow sets 3-4 inches apart and space your rows about 12 inches apart.

Growing onions in a container is possible as well.  Purchase a container that is about 8 inches wide and 6 inches deep.  Plan on planting approximately 8 sets or seedlings in the container and water regularly.

Water lightly and continue to water regularly throughout the season.  Watch out for weeds as they will suck necessary nutrients meant for your onions.

You may expect to harvest 3-4 months after planting.  Look for the foliage to turn yellow and simply pick your onions.  You are able to pick them sooner than this as they will be edible earlier.