What Happens to Your Body When You Eat Onions Every Day

Onions can give you a boost of flavor and nutrition in every bite.

a recipe photo of the Melting Onions
Photo:

Jacob Fox

Including the humble onion in your daily meals might not sound like your conventional path to wellness. However, it actually offers some impressive benefits. Adding onion to your dishes doesn’t just give them a zesty kick; it also positively impacts your health. 

If you love onions and wonder what happens to your body when you eat these pungent veggies, get ready to cry tears of joy. This article will peel back the layers of what eating onions means for your health and wellness. 

Onion Nutrition Facts

Onions are a natural source of vitamins, minerals and plant compounds wrapped in a tasty package with many layers. While onions come in different varieties (think yellow, red and even a sweet Vidalia) and may vary in flavor and culinary applications, they are all similar in their nutritional composition. However, some have extra-impressive features that we will get into later. 

The following information shows the nutrition provided by onions.

Nutrient White onion (100 g) Red onion (100 g) Yellow onion (100 g)
Calories 33 42 36
Carbohydrates 8 g 10 g 9 g
Total Sugars* 6 g 6 g 6 g
Dietary Fiber 1 g 2 g 2 g
Protein 1 g 1 g 1 g
Total Fat 0 g 0 g 0 g
Saturated Fat 0 g 0 g 0 g
Vitamin C NA 16 mg 8 mg
Sodium 1 mg 1 mg 1 mg
Calcium 21 mg 8 mg 15 mg
Potassium 141 mg 197 mg 182 mg
Magnesium 9 g 11 mg 9 g
*Sugars in onions are naturally occurring ones.

Health Benefits of Onions

Onions are perhaps best known for their pungent, sharp and savory taste, especially when eaten raw, providing an intense, zesty kick that can bring any dish to life. And when sautéed or caramelized, onions develop a delightful sweetness accompanied by a mellow, slightly buttery taste, adding depth and richness to a variety of dishes. 

If you add onions to your dishes regularly, here are some effects you may observe.

May Support a Healthy Gut

Onions are a natural source of prebiotics, which are necessary for optimal gut health. Prebiotics are non-digestible fibers that serve as food for the beneficial gut bacteria, promoting their growth and encouraging a balanced gut flora. 

Specifically, onions contain the prebiotic inulin, which helps stimulate the growth of healthy bacteria. Evidence suggests that allicin, a compound found in onion, may also help support a healthy gut, but more quality human-based data is needed to confirm this.

May Improve Your Heart Health

Regular consumption of onions also supports heart health. Onions contain anti-inflammatory and antioxidant properties, especially quercetin, that may have antihypertensive effects. Additionally, quercetin has been shown to help decrease triglycerides and reduce cholesterol levels. Evidence suggests that eating onion can not only be helpful in preventing and treating dyslipidemia and high blood pressure but ultimately may help reduce the risk of developing cardiovascular disease.

Might Benefit Your Eye Health

Onions are also helpful for supporting good eye health. They are rich in sulfur, which is important for producing glutathione, one of the body's most potent antioxidants. This antioxidant, in particular, is necessary for the eyes' health, helping to prevent age-related macular degeneration, cataracts and glaucoma. Therefore, incorporating onions into your diet can potentially support and maintain good eye health.

Might Reduce Your Risk of Certain Cancers

Notably, onions may also contribute significantly to cancer prevention. They are rich in antioxidants and sulfur-containing compounds that may potentially reduce the risk of certain types of cancer, including lung, prostate and stomach. 

One study assessed primary breast cancer cases among a sample of women in Puerto Rico. Results of the study suggest that high onion and garlic consumption may be protective against breast cancer among this population. Other data has shown that there may be a link between eating more foods that contain allicin, like onions, and a reduced risk of stomach cancer. That said, more robust research is needed to confirm these findings.

Have Antibacterial Properties

Onions may also have antibacterial properties to help fight off dangerous bacteria and reduce infections. Research suggests that onion essential oils could help reduce bacteria such as Staphylococcus aureus and Salmonella.

Potential Downsides

Despite the myriad benefits of consuming onions, they may not be suitable for everyone. Here are some potential downsides to eating onions regularly.

May Cause Digestive Discomfort

The presence of fructans, a type of complex carbohydrate, can trigger digestive discomfort in some individuals. These compounds can cause bloating, flatulence and stomach cramps, particularly in those with irritable bowel syndrome (IBS) or other sensitivities to FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols). Consequently, while onions are generally a beneficial addition to most diets, individuals with digestive conditions may need to limit their intake or opt for cooked onions, which are often better tolerated.

May Cause Allergic Reactions

While cases are rare, onions can trigger allergic reactions in certain people. Symptoms may range from mild, such as itching or rash, to severe, like breathing difficulties or anaphylaxis. Therefore, those with known onion allergies need to do some homework to make sure they eat safe dishes with no onions included. And if you think you might have an allergy to onions, speak with your health care provider.

May Cause a Bad Breath

Another drawback to consuming onions is their potential impact on breath odor. Due to their high sulfur content, onions can cause bad breath, or halitosis, which may persist for several hours after consumption. This can pose social discomforts and may require individuals to employ techniques such as proper oral hygiene or breath-freshening products to counteract the effects.

Best Ways to Cook and Enjoy Onions

Onions can be a delicious addition to your dishes. And thankfully, there are many interesting ways to cook and enjoy them. 

Caramelized

One of the best ways to cook and enjoy onions is by caramelizing them. Caramelization brings out the inherent sweetness of onions, providing a rich, complex flavor that can enhance many dishes. To caramelize onions, begin by slicing them thinly. Then, heat a pan over medium-low heat. Add a drizzle of olive oil or a pat of butter, followed by the onions. Simmer the onions, stirring occasionally. As they cook, the onions will start to soften and turn a deep golden brown. This process may take anywhere from 30 to 45 minutes. Patience is key here; rushing this process may result in burnt onions. Once fully caramelized, they are ready to be used in your favorite dish or as a delightful topping for burgers, pizzas or steaks. Remember to adjust the seasoning with salt and possibly a splash of vinegar to balance the sweetness. Try our Caramelized Balsamic Onions for a unique twist on a classic.

Roasted

Roasting is another fantastic way to prepare and savor onions. This cooking method highlights onions' natural sweetness and imparts a delightful, toasty flavor. To roast onions, first preheat your oven to 400°F. Meanwhile, peel and quarter the onions. Toss them in a mix of olive oil, salt and pepper, then arrange them in a single layer on a baking sheet. Roast for about 25 to 30 minutes, or until the onions are tender and have developed a deep, golden brown color. Roasted onions pair wonderfully with roasted meats, or try them in salads or as a flavorful addition to a cheese board. Enjoy this simple yet satisfying way of cooking onions. Our Melting Onions are a mouthwatering way to enjoy roasted onions. 

Grilled

Grilling onions is yet another excellent method to unlock their flavor potential. The grill's high heat chars the onions' outside, giving them a smoky taste, while the inside becomes tender and sweet. To grill onions, peel them and cut them into half-inch rounds. Then, brush both sides with olive oil and season with salt and pepper. Arrange the rounds on a preheated grill over medium heat. Grill them for about 4 to 5 minutes on each side, or until they have prominent grill marks and have softened. These grilled onions serve as a perfect condiment for meats or as an addition to summer salads. This method offers an easy, flavorful and healthful way to enjoy onions. Our Grilled Blooming Onion is a satisfying option to try if you want grilled onions on your menu.

Raw

Eating onions raw is another way to enjoy their unique flavor and reap their health benefits. Raw onions, especially red ones, are a common ingredient in salads due to their crisp texture and pungent, spicy flavor that adds a zesty punch. Raw onions are also used in salsas, sandwiches or ceviche. To prepare, peel the onion, slice it thinly or dice it, and add it raw, depending on your dish. Remember to use them sparingly, as their flavor is robust and can overpower other ingredients. If the raw onion's taste is too strong, you can soak the sliced onions in cold water for 10 to 15 minutes to mellow their sharpness. Another great way to enjoy raw onions is by pickling them.

Frequently Asked Questions

Can You Eat Onions Every Day?

Consuming onions daily can be beneficial, due to their rich nutrient content and numerous health properties. However, they may cause digestive discomfort to certain people, especially those with digestive issues.

Are Onions Healthier Raw or Cooked?

Both raw and cooked onions have health benefits, though these can vary. Raw onions retain their full complement of vitamins and antioxidants, making them a slightly healthier option if you're looking to maximize your intake of nutrients. However, cooking onions can break down some of their hard-to-digest fibers, making them easier for some people to eat.

Are Onions a Superfood?

Given their rich, nutrient-dense profile and numerous health benefits, one could argue that onions could be classified as a "superfood." However, it's important to remember that "superfood" is not a scientific term but a marketing term, and no single food, not even onions, can provide all the nutrition our bodies need.

Which Organs Benefit Most from Onions?

Several organs in the body can benefit substantially from the consumption of onions. The heart is one of the primary beneficiaries due to the antioxidant flavonoids in onions, which can help reduce heart disease risk by lowering blood pressure and cholesterol levels. The digestive system also benefits from onions as they promote healthy gut bacteria.

The Bottom Line

So, are onions the unsung heroes of the produce aisle, effortlessly boosting our health with every crunch? It would seem so. Their unique blend of nutrients and potent antioxidants gives them a well-deserved spot in our daily diets. But don't ditch your apples and broccoli just yet. Remember, in the concert of good nutrition, onions may play a stellar solo, but the symphony of varied fruits, vegetables, whole grains and lean proteins makes the music of a healthy body. So, enjoy those onions, but make sure they share the stage with plenty of other nutritious foods, too. 

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Sources
EatingWell uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable and trustworthy.
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