Skip to Content

Why Do Onions Give Me Heartburn? (Quick Read)

Onions are a delicious veggie similar to garlic, shallows, leeks, and chives. They’re loaded with vitamins and minerals that contribute to good health, making them a great addition to any diet.

But have you ever had too many onions in one sitting and felt the unpleasant burning sensation in your throat? Onion-triggered heartburn is quite common, but the question remains: Why does it happen?

Why do onions cause heartburn?

Onion has a sharp taste, which irritates and inflames your esophagus as you eat it. Because of that, eating onion, especially in high amounts, has been closely linked with heartburn.

Luckily, eating onions doesn’t seem to lead to heartburn for people who don’t suffer from acid reflux or GERD. So, always listen to your body and adjust your diet accordingly to avoid any unpleasant symptoms.

Are onions acidic?

What Kinds of Onions Are There?
Different Kinds of Onions

Raw onion has a pH level of around 5.37-5.85. While this is low, onion is actually alkaline-forming once digested and metabolized. Unfortunately, this doesn’t matter for those of us who suffer from heartburn.

Due to its sharp and intense taste and flavor, eating onion has been linked with a much worse occurrence of acid reflux-like symptoms. 

This vegetable also tends to irritate your esophagus once it’s moving down your digestive tract.

Pickled onion has a much lower pH level, ranging between 3.70-4.60. It’s also much higher in sodium and added sugars, which are bad for your health and can increase the frequency of heartburn.

Unlike raw onion, pickled onion is acid-forming. So, it might be best to avoid it if you’re following a low-acid diet or suffer from frequent acid reflux symptoms.

Don’t know what to drink? We made a list of more than 20 most and least acidic juices and 20+ alcoholic drinks ranked by acidity levels.

How does onion cause heartburn?

One of the most common reasons onions lead to heartburn is because of their taste. Some people even refer to onions as spicy since they have a very strong aroma. 

This is due to some plant compounds found in them. These plant compounds irritate and inflame your esophagus as you eat onions, leading to that uncomfortable burning sensation in your throat and chest.

Eating onions might also relax the lower esophageal sphincter muscles between your esophagus and stomach. 

Spanish Onion
Spanish Onion

These muscles are meant to keep the stomach contents down. So, when they’re relaxed, you’re more likely to experience acid reflux symptoms.

In addition, onions contain a lot of FODMAPs, which are non-digestible carbohydrates that cause digestive issues in some people. 

This, in turn, can lead to indigestion, which may give your heartburn and other issues. So, that’s another way onions can cause these problems.

Is onion good for you?

Firstly, onions are very nutrient-dense and low in calories. This veggie is especially high in vitamin C, providing you with around 7% of your daily need for this micronutrient in just one slice.

Vitamin C is involved in various bodily processes, including immune health regulation, tissues repair, collagen production, and iron absorption. It also acts as a powerful antioxidant and helps with wound healing.

Onions also contain plant compounds that reduce inflammation in your body, lowering your risk of heart disease. 

This is because these anti-inflammatory compounds lower your blood pressure and protect against blood clots

These plant compounds also have antioxidant properties. As a result, eating onions can help flush out free radicals from your body, preventing oxidative stress and damage to your cells and reducing your risk of cancer and diabetes.

Red Onion
Red Onion

Experts also believe that eating onions can help control your blood sugar levels. This is especially important for people genetically predisposed to diabetes and high blood sugar levels.

What’s more, keeping your blood sugar levels in check can aid in weight loss by curbing your appetite and preventing overeating. 

This benefit might have a lot to do with the fiber found in onions as well as with the plant compounds they contain.

Additionally, extracts from onions have been shown to fight against dangerous bacteria in your body. 

Studies show that onions can help protect you against bacteria that cause stomach ulcers, destroy cells walls, and cause various infections.

Because of these antibacterial properties, onions can be a powerful addition to a diet that strengthens the health of your immune system.

Should you eat onion on acid reflux?

Onions are often considered to be a trigger food for people with acid reflux and GERD. Because of that, you may want to limit how often and how much onion you consume. 

Some people with acid reflux might be able to tolerate some onion in small amounts. So, if that’s the case for you, try adding it to your diet, as it contains lots of powerful antioxidants that help you stay healthy.

Is onion soup bad for acid reflux?

Onion soup might not lead to heartburn, but it depends on how you make it. Most people consume store-bought onion soups, which are either canned or in the form of dry mix. 

Because of that, these products tend to contain preservatives like salt, which are bad for your health.

Why Do Onions Give Me Heartburn?
Why Do Onions Give Me Heartburn?

For example, one serving of store-bought onion soup can contain nearly 50% of your daily need for sodium. 

This mineral, in large quantities, can raise your blood pressure and increase the risk of strokes and heart attacks.

Sodium is also not good for acid reflux, as it may lead to inflammation in your stomach. So, if you want to consume onion soup, you might be better off making it yourself to ensure you know what’s in it.


While onions have some alkaline-forming properties, people with acid reflux and GERD should avoid consuming too many of them. 

They not only contain some plant compounds that lead to heartburn but also have a sharp taste that irritates your digestive tract.

Because of that, try limiting your consumption of onions if you notice that they are a trigger food for you. 

On the other hand, if you don’t suffer from acid reflux, eating onions can help you reap some great health benefits and load up on vitamins and minerals.

So, at the end of the day, it all depends on how your digestive system tolerates the foods you eat.

Don’t know what to drink? We made a list of more than 20 most and least acidic juices and 20+ alcoholic drinks ranked by acidity levels.

Sources: National Library of Medicine, Nutrition Data, PMC, Arrow Scientific