Do Onions Cause Heartburn and Acid Reflux?

Can onions cause acid reflux?

For many people, the answer is yes—especially when onions are eaten raw or are particularly sharp or pungent. Onions are among the most common dietary triggers for acid reflux, and their effects are well-documented in both clinical research and patient experience.

In this article, we’ll explore why onions cause acid reflux, which varieties are most problematic, and how to prepare them in ways that may reduce symptoms.

Why Onions Cause Acid Reflux

Onions are part of the allium family, which also includes garlic, shallots, and leeks. What gives onions their strong flavor—and their tear-inducing qualities—are sulfur-containing compounds known as thiosulfinates.

These sulfur compounds can contribute to acid reflux through two main mechanisms:

• Increasing gastric acid production
• Relaxing the lower esophageal sphincter (LES), the muscle that normally keeps stomach contents from rising into the esophagus

This is why the more pungent the onion, the more likely it is to cause acid reflux.

In fact, if you cry when cutting an onion, that’s your body reacting to a sulfur compound that forms when the onion’s cells are damaged. More tears often indicate higher sulfur content—and a greater likelihood of triggering reflux.

It’s also important to note that raw onions are significantly more irritating than cooked ones, and sharp varieties are more likely to cause symptoms than sweet onions.

Onions are also high in fructans, a type of fermentable fiber that can produce gas and bloating in people with sensitive digestion. This can increase intra-abdominal pressure and make reflux symptoms worse—even when the onions are cooked.

Who Should Avoid Onions?

The connection between onions and acid reflux has been confirmed by research. One well-done study, titled The Effect of Onions on Acid Reflux, looked at how onions impact people with and without reflux. Participants with diagnosed acid reflux were given the same meal on two consecutive days—one with onions and one without. The same meals were also served to a control group without reflux.

The results were clear: onions worsened reflux symptoms in those with the condition but had no effect on the control group. This suggests that onions can aggravate reflux in those who already have it, but once reflux is under control, onions may be tolerated again—as long as they’re well cooked.

If you’re currently experiencing daily acid reflux, it’s best to avoid onions altogether, along with other sulfur-rich foods like garlic, tomatoes, and peppers. These foods are excluded from my Reflux Detox Diet, which is typically followed for at least three weeks during the initial healing phase.

Best and Worst Onions for Acid Reflux

Not all onions are created equal. Their pungency depends largely on the sulfur content of the soil they’re grown in. The more sulfur, the sharper the onion—and the more likely it is to aggravate reflux.

As a general rule, if an onion makes you cry when cutting it, it may be too sharp for someone with reflux.

Dr. Koufman’s Onion Pungency and Reflux Ranking:

Sharp (Worst for Reflux):

• Red onions (especially raw)
• Yellow onions (strong and tear-inducing)
• Shallots (3 shallots equal one onion in potency)
• Spring (green) onions

Moderate (Better Choices When Cooked):

• Leeks (best when slowly cooked)
• Chives (small amounts, used as garnish)

Mild (Best Choices):

• White sweet onions
• Sweet Vidalia onions (most recommended)

If you’re still in the detox phase, it’s best to focus on healing and avoid onions altogether. Once symptoms improve, you can begin with sweet onions—these are clearly labeled in grocery stores as “sweet” or “Vidalia,” and should not be confused with standard yellow onions.

Below is a visual summary showing how common onions rank in terms of reflux potential—from the sharpest and most irritating to the mildest and most reflux-friendly.

(Note: Chives are best used sparingly as a garnish.)

Why Vidalias Are the Best

Among sweet onions, Vidalia onions are the gold standard. Cultivated since the 1930s, the name “Vidalia” is legally protected and only applies to onions grown in a specific region of Georgia. Vidalias are squat in shape and exceptionally sweet.

Their mild flavor comes from the naturally low sulfur content in the local soil—making them ideal for people with reflux. I consider the Vidalia to be onion royalty.

How to Cook Onions for Reflux

Cooking onions not only brings out their sweetness—it also breaks down many of the volatile sulfur compounds that trigger reflux. Even sharp onions become milder when thoroughly cooked, though if you’re early in your healing journey, stick with sweet onions only.

Here’s how I recommend preparing them:

• Cook sweet Vidalia onions in olive oil over high heat with the lid on, stirring occasionally, until they turn clear.
• Then reduce the heat and continue cooking slowly, stirring often, until they caramelize.

These golden, tender onions are naturally sweet and flavorful enough to be used as a pasta sauce—just add basil, olive oil, and a small amount of grated Parmesan.

Conclusion: Can You Eat Onions with Reflux?

Yes—but timing matters. Onions can be a significant trigger for acid reflux, particularly when eaten raw or in more pungent varieties. If you’re actively experiencing symptoms, it’s best to avoid onions and other trigger foods while your system heals.

Once symptoms improve, you may be able to reintroduce sweet, well-cooked onions—such as Vidalias. Pay close attention to how your body responds, and don’t rush the process.

Managing reflux well means knowing when to avoid certain foods and how to reintroduce them thoughtfully. Timing and preparation truly matter.