Onions and Acid reflux (with Scientific evidence)


Whether onions are acidic or not goes a long way in determining how it affects acid reflux or heartburn patients. If you are not familiar with how acid reflux occurs, it happens when some of the acidic content in the stomach backs up into the esophagus; an action that creates a burning sensation in the lower chest area, usually after eating acidic foods.


Are onions acidic or alkaline?

Since eating acidic foods is one of the main culprits of heartburn, I decided to create this post to make awareness on the acidity in onions, since it is one of the most consumed vegetables in the world. Onions however, are of many varieties. According to Oriental Detox site, the pickled onions have a pH of 3.70-4.60. Red onions have a pH of 5.30-5.80, while the white and yellow onions have a pH of 5.37-5.85 and 5.32-5.60 respectively (1).

The pH values of all the above varieties show that onions are acidic in nature, with the pickled onions being more acidic than the others. As a reminder, a pH scale is used to determine the level of acidity or alkalinity of a substance. It runs from 0-14, with values from 0-6.9 representing acidity, and those from 7.1-14 representing alkalinity. An intermediate value of 7.0 depicts a neutral state.

Onions and heartburn or acid reflux

Since onions are acidic, then they are bound to cause symptoms in people with acid reflux. Many people have stressed that onions must be included in the list of forbidden food items for people suffering from this disease. Physiologists have attributed the intake of onions, especially raw ones, to have a huge impact in weakening the lower esophageal sphincter muscle, which is responsible for holding back the acidic content of the stomach, and preventing it from coming up into the esophagus.

A research published way back in the 90s, used a total of 32 people to determine the effect of ingesting raw onions on acid reflux and its symptoms. The research divided the people into groups; some were fed a plain hamburger with a glass of water, while others were fed an identical meal, but with an additional slice of onion (2).

At the end of the research, it was found that ingestion of onions did not increase any acid reflux symptoms in people that were normal, but it however significantly increased acid reflux symptoms such as heartburn, belches, etc in people that already has acid reflux. This research concluded onion to be potent and even a long-lasting trigger of acid reflux in heartburn patients.


Onions are acidic, and can cause heartburn and other symptoms in people with acid reflux. They however rarely cause any symptom in people without acid reflux disease. There are chances that even if you have this disease, you might be able to eat and tolerate onions in your system.

If you are unsure about the effect of onions on your body system, you can use the food-symptom log technique to keep an eye on how your body reacts to its consumption. You can do this by eliminating most other key foods in your diet, and then adding onions to see if there are any possible negative effects.

By Abbati

Abbati studied Biological sciences at Ahmadu Bello Univeristy, Zaria. He loves learning about the medicinal properties of foods, and the need to explore them!

Leave a Reply