Any time you go to the supermarket, you likely toss an onion or two into your cart without thinking twice about it; it’s an easy addition to top your salads or flavour your meals. But, the nutritional value of the veggie is often overlooked, often seen as a way to simply to amp up the taste of your food.
“Onions are very much a forgotten vegetable with lots of benefits and flavour,” says culinary and integrative dietitian Marisa Moore.
We tapped Moore and dietitian Natalie Rizzo, to peel back the layers for us on all the health benefits of onions.
What are the health benefits of onions?
Thanks to the presence of certain phytochemicals (plant chemicals that contribute to their color, taste, and smell), including disulfides and trisulfides, onions may help ward off chronic diseases, such as heart disease and certain cancers, as part of a balanced healthy diet, Moore says. Plus, onions contain some fiber, vitamin C, and folate, among other nutrients, which can be helpful for boosting health and performance.
How can runners benefit from adding onions to their diet?
Onions contain a beneficial anti-inflammatory compound, known as quercetin. This compound can help reduce the effects of post-workout inflammation in athletes, says Rizzo. Plus, a recent study published in the Journal of Functional Foods found that the quercetin in onions may act as an anti-inflammatory agent.
Though there may not be enough to make a measurable difference in your diet just through eating onions alone, Moore says, so be sure to hydrate, stretch and eat a nutritious meal to help with postworkout recovery as well.
How often should you eat onions?
There’s no one recommended frequency, so you can eat onions as often as you please, says Moore.
However, Rizzo points out some athletes might find that onions cause GI distress if eaten before exercise. So, you might want to avoid them for that reason, or time your meals with onions around your workouts. But if you can eat onions and feel great, it’s fine to eat them daily, but like everything else, in moderation.
Are certain types of onions better for you than others?
Red onions also contain some anthocyanins (the same antioxidant found in berries), which may promote healing and recovery, but most onions provide similar benefits, says Moore.
Remember, that there are different onions with varying levels of pungency, so what you eat may be based on your individual taste. For example, shallots are quite mild, and white onions are more pungent.
Is there a difference in nutrition between cooked and raw onions?
Yes. Cooked onions may contain less vitamin C than raw onions because of water loss, Moore says. Quickly steaming or sautéing onions will allow you to retain the most nutrients.
“But, it’s also fine to include them in soups and stews [which cook] for longer since you’ll eat the broth,” Moore says.
And keep in mind, fresh and frozen are exactly the same, says Rizzo. Frozen veggies are picked at the peak of freshness and flash frozen to lock in nutrients.
“The difference between fresh and cooked veggies is minimal, but you’ll also want to consider what you use to cook the veggie,” Rizzo says. “For instance, if you use oil, that adds calories and fat to your meal.”
How can you add onions to your diet?
There are many ways you can eat onions, and if you don’t like them prepared one way, try others before you write them off completely. Moore suggests adding onions as a crunchy, spicy, flavorful ingredient in fresh salsa or relish. Depending on your personal preferences, putting them in a variety of cooked meals including sauces, stews, and soups, will give you a savory flavor, and grilling or roasting them gives you a sweet, standalone vegetable.
Additionally, your spice cabinet may already have onion powder. The spice is just dehydrated onions, so it’s essentially the same nutrient profile, says Rizzo. The difference is that you would only use 1 tablespoon of onion powder to replace 1 medium onion in a recipe.
One tablespoon of onion powder has about half the nutritional benefits of an actual onion. For instance, an onion has 50 calories, while onion powder has about 20 calories. And an onion has about 200 mg of potassium, while 1 tbsp of onion powder has 70 mg.