What Happens to Your Body When You Eat Onions Every Day

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

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a recipe photo of the Melting Onions
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Jacob Fox

  • Onions benefit heart health and may help reduce the risk of certain cancers.
  • Onions are rich in fiber and powerful plant compounds, including antioxidants.
  • Enjoy onions raw, caramelized, roasted, grilled or pickled.

Including the humble onion in your daily meals might not sound like your conventional path to wellness. However, onions offer some potentially impressive benefits. Adding onion to your dishes doesn’t just give them a zesty kick; it can also positively impact 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. We'll peel back the layers of what eating onions means for your health and wellness. 

Why We Love 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 benefits you may gain.

They 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 onions, may also help support a healthy gut, but more quality human-based data is needed to confirm this.

They May Improve Your Heart Health

Regular consumption of onions also supports heart health. Onions contain anti-inflammatory and antioxidant properties, especially quercetin, which may help regulate blood pressure. While more human studies need to be conducted, quercetin may also help decrease triglycerides and reduce cholesterol levels. Evidence also suggests that eating onions may help reduce the risk of developing cardiovascular disease through several mechanisms, including lowering the risk of metabolic syndrome by supporting healthy blood sugar and systolic blood pressure.

They 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 healthy eyes, helping to prevent age-related macular degeneration, cataracts and glaucoma. Therefore, incorporating onions into your diet can potentially support and maintain good eye health.

They Might Reduce Your Risk of Certain Cancers

Onions may also contribute to cancer prevention. They are rich in antioxidants and sulfur-containing compounds that may potentially reduce the risk of certain types of cancer, including prostate and cervical cancer, in laboratory settings.

Other data have 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.

They Might 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.

Nutrition Information

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. 

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

*Sugar in onions is naturally occurring

Are Onions Safe for Everyone?

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

They 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.

They Might Cause Allergic Reactions

Though considered to be 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 healthcare provider.

They May Cause 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.

4 Ways to 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.
  • Roasted: Roasting is another fantastic way to prepare and savor onions. This cooking method highlights onions' natural sweetness and imparts a delightful, toasty flavor. Roasted onions pair wonderfully with roasted meats, or try them in salads or as a flavorful addition to a cheese board. 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. 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.
  • Pickled: Pickled onions are a great addition to any sandwich, burger or salad. You can make them yourself or buy them. You'll usually find them in the pickled items section of your grocery store.
  • 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. If the taste of raw onion is too strong, you can soak the sliced onions in cold water for 10 to 15 minutes to mellow their sharpness.

Onion Recipes to Try

Our Expert Take

Onions' 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, lean proteins and healthy fats 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. 

Frequently Asked Questions

  • Can you eat onions every day?

    Consuming onions daily may 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 possibly cholesterol levels. The digestive system also benefits from onions as they promote healthy gut bacteria.

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Sources
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