And yet, behind its layers and unmistakable aroma, it hides far more than just a simple role as a flavor enhancer. While onions are often praised as a superfood, they can also bring a few surprises for people with sensitive systems. So, should we eat them freely, or with a bit more awareness? Let’s take a gentle look.

Why onions are so good for us

If onions have conquered kitchens around the world, it’s no coincidence. They’re packed with naturally beneficial compounds that support a balanced diet. In particular, they contain antioxidants that help the body cope with everyday stressors and support the immune system.

Another important benefit: onions contribute to cardiovascular health and easily fit into a varied diet without making dishes heavy. Rich in vitamin C and sulfur compounds, they’re often associated with a sense of vitality and lightness—provided they’re well tolerated.

On paper, onions are undeniably good for your health.

When onions are less friendly to your stomach

Things get a bit more complicated when it comes to digestion. Some people notice bloating, discomfort, or a swollen belly after eating onions, especially when they’re raw.

The reason is simple: onions contain fermentable fibers that can be difficult for sensitive intestines to digest. The result may be gas, digestive discomfort, or a feeling of heaviness.

The game-changing tip: cooking. Sautéing, simmering, or caramelizing onions makes them much gentler on the digestive system while preserving their flavor.

Raw onions: not always a friend to the stomach

If you’re prone to heartburn or acid reflux, raw onions can sometimes make the discomfort worse. Their sharp taste and texture may irritate more delicate stomachs.

That said, there’s no need to eliminate them completely. Eating smaller amounts or choosing cooked versions often helps prevent these issues while still letting you enjoy their flavor.

A mild blood-thinning effect to keep in mind

Less well known, but useful to remember: onions naturally have a mild blood-thinning effect. This isn’t a concern for most people, but it’s a good reminder of an essential rule in nutrition— even the healthiest foods are best enjoyed in moderation.

If your diet is already rich in foods with similar effects, varying your ingredients is always a smart idea.

Raw or cooked: do you really have to choose?

Good news: there’s no need to pick a side. Each version has its own advantages.

Raw onions retain more vitamin C and add freshness and crunch to salads.

Cooked onions are milder, easier to digest, and incredibly versatile in the kitchen—ideal for more comfortable digestion.

The best approach? Alternate based on your preferences, your tolerance, and the season.

Why do we cry when cutting an onion?

You can’t talk about onions without mentioning this classic reaction. When cut, onions release a sulfur compound that slightly irritates the eyes, causing tears. Rest assured, it’s harmless and temporary.

To reduce the tears, try placing the onion in the refrigerator for about 15 minutes before cutting it, or use a very sharp knife, which crushes fewer fibers.

What’s a reasonable amount?

In practical terms, about 30 to 50 grams of raw onion (roughly a quarter of a medium onion) or 100 to 150 grams of cooked onion (about one medium onion) per day suits most people.

The key is to listen to your body. If you experience bloating or digestive discomfort, reduce the amount or opt for well-cooked onions, which are easier to digest.

Onions are a wonderful everyday ally—as long as you adapt them to your needs and your own digestive comfort.