August 22, 2022

Do Onions Cause Heartburn and Acid Reflux?


  • Onions are a common reflux trigger food; and the sharper (more pungent) the onion; the worse it is for heartburn, GERD, respiratory reflux, aka LPR. The mechanism is that the high sulphur content of some onions can increase gastric acid and relax the lower esophageal sphincter.
  • When it comes to reflux, not all onions are created equal. If an onion makes you cry when you cut it, it is too strong; and regardless of type, cooked onions are much better than raw. But, if you have daily reflux, avoid all onions.
  • Which onion is okay, and when? Provided is Dr. K’s reflux ranking of the onion family … which onions are best and worst for refluxers … and the best way to cook onions.

Different members of the onion family contain different amounts of sulphur, which is what makes you cry when you cut them. The sharpness or pungency of an onion has to do with how much sulfur is in the soil in which it is grown. The sulphur compounds, called thiosulfinates, are responsible for causing or worsening acid reflux by increasing gastric acid and relaxing the lower esophageal sphincter. And notably, across the board, pungent onions are worse than sweet ones, and raw onions are far worse than cooked ones.

Who Should Avoid Onions?

The effect of onions on acid reflux is a well-done study. On two consecutive days, they gave identical meals — one day with onions and one day without — to a group of known refluxers with heartburn and to a group of “normals” (non-refluxers). Onions made the heartburn/reflux group’s reflux worse by every measure, but not the normal controls. The authors concluded, “Onions can be a potent and long-lasting refluxogenic agent in heartburn [reflux] patients.” This study implies that when and if you beat your reflux, you will be able to eat onions again … cooked preferred.

Whether or not you should avoid onions actually depends on the severity of your reflux; if you have daily symptoms, you should probably go on my Reflux Detox Diet for at least three weeks, no onions … also prohibited would be garlic, tomatoes, and peppers. (BTW, like onions, garlic contains similar sulphur compounds.)

What Are the Best and Worst Onions for the Refluxer?

Onions are a common reflux trigger food; the sharper, more pungent, the onion, the more likely it is to cause reflux. If you cry when cutting an onion, it is too strong for you if you are a refluxer.

Dr. Koufman’s Onion Family Pungency and Reflux Ranking


Red Onions (strongest onion esp. raw)

Yellow Onions (will make you cry)

Shallots (3 shallots equal one onion)

Spring (Green) Onions


Leeks (best cooked slowly)

Chives (just as a garnish)


Sweet (White) Onions

Sweet Vidalia onions (the Best)

After the detox phase of your anti-reflux diet, you may want to add back onions. If you do, they should be sweet onions. These are always labeled as such in the grocery. Of the sweet onions, I recommend the Vidalia, which is Georgia’s official state vegetable. This squat (flat-ish) onion is one of several sweet onions grown mostly in the south. The cultivation of Vidalia onions started in the 1930s in, to no surprise, the town of Vidalia Georgia. The unusual sweetness of Vidalia onions (and all other sweet onions) comes from the low sulfur content in the soil in which they are grown. I consider the Vidalia to be  “Onion Royalty.”

How Do I Cook My Onions?

Because they are delicious, I always cook with sweet onions; and when you cut sweet onions, you don’t cry, so these onions are much better for you refluxers. By the way, I would put shallots in the sharp group and cooked leeks and chives in the “better” (relatively mild) group.

I cook sweet Vidalia onions in olive oil at a high temperature with the lid on (with an occasional stir) until they are clear, and then I cook them slowly at a low temperature with stirring to prevent burning until they are caramelized. These caramelized onions are so sweet and delicious that they can be used with basil and olive oil as a stand-alone pasta sauce, perhaps with a small amount of grated parmesan as a top-off seasoning.

In conclusion: It is important to remember that onions will affect you differently depending upon the stage and severity of your reflux. If you are having daily problems with heartburn or LPR symptoms, then you should probably avoid onions altogether as well as other known Trigger Foods. Once the reflux is under control, then I would introduce sweet cooked onions as above.

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