Does Tomato Soup Increase Acidity? The Truth Behind Heartburn

November 19, 2025 •

4 min read

According to gastrointestinal specialists, tomatoes and their byproducts are among the most common dietary triggers for acid reflux and GERD. This naturally leads to the question: does tomato soup increase acidity, and is it a trigger for heartburn and other digestive issues?

Quick Summary

Tomatoes are a naturally acidic food and can increase stomach acid levels, potentially triggering acid reflux and heartburn in susceptible individuals. The effect varies by person and recipe, but acidic foods like tomatoes can relax the lower esophageal sphincter, allowing stomach acid to flow back into the esophagus.

Key Points

Tomatoes are Naturally Acidic: Tomatoes have a pH between 4.1 and 4.7, and this inherent acidity is a major reason why tomato soup can trigger acid reflux and heartburn.
Soup Concentrates Acidity: The process of cooking and concentrating tomatoes for soup can increase their overall acidity, making them a more potent trigger for sensitive stomachs.
Affects the Lower Esophageal Sphincter: The acidity in tomato soup can cause the LES muscle to relax, allowing stomach acid to flow back into the esophagus and cause discomfort.
Mitigate Acidity with Alkaline Additions: Ingredients like baking soda, powdered milk, or alkaline vegetables such as carrots can help neutralize the acid in tomato soup.
Preparation Matters: Canned tomatoes often have added citric acid, and other ingredients like garlic, onions, and heavy cream can worsen symptoms.
Individual Tolerance Varies: The effect of tomato soup on acidity is highly individual; some people with GERD can tolerate it, while others must avoid it entirely.
Health Benefits Still Exist: Despite the acidity issues, tomatoes are packed with nutrients and antioxidants like lycopene, which support heart health and immune function.

Understanding Tomato Acidity

Tomatoes, though a fruit, are known for their acidic nature, typically having a pH between 4.1 and 4.7. This inherent acidity is what gives them their tart flavor and can be problematic for those with sensitive digestive systems or conditions like gastroesophageal reflux disease (GERD). When tomatoes are used to create soup, their concentrated acidity is a primary concern for many.

How Tomato Acidity Affects the Body

The main mechanism by which tomatoes can cause issues is through their effect on the lower esophageal sphincter (LES). The LES is a ring of muscle that acts as a valve, separating the stomach from the esophagus.

Relaxation of the LES: Acidic foods can cause the LES to relax, allowing stomach acid to splash back up into the esophagus. This is the root cause of acid reflux and its associated symptoms, such as heartburn.
Increased Stomach Acid: The high acid content of tomatoes can also stimulate the stomach to produce more acid, exacerbating the problem.
Flavor Perception: Interestingly, some yellow tomato varieties are perceived as less acidic because of their higher sugar content, even though their pH is often similar to red tomatoes. This perception does not change their potential to trigger reflux.

Factors That Influence the Effect of Tomato Soup

It is not just the tomatoes themselves that can cause issues. The preparation and ingredients used in tomato soup can significantly affect its impact on acidity. Common additions can either worsen or mitigate the problem.

Added Ingredients: Heavy creams, rich fats, onions, and garlic are common additions that can worsen acid reflux symptoms. These ingredients can further relax the LES or slow down digestion, increasing pressure on the stomach.
Cooking Methods: The type of tomato used (fresh vs. canned) and the cooking process matter. Canned tomatoes often have added citric acid for preservation, which can increase overall acidity. Cooking them down concentrates the natural acids.
Individual Sensitivity: Not everyone with GERD is triggered by tomatoes. Some people can tolerate small amounts, while others must avoid them completely. Keeping a food journal can help determine personal triggers.

Reducing Acidity in Tomato Soup

For those who love tomato soup but suffer from reflux, several culinary techniques can help neutralize or reduce the acidity. These adjustments can make the dish more palatable for sensitive stomachs.

Tips for a Less Acidic Soup

Add an Alkaline Base: Adding a small amount of baking soda (sodium bicarbonate) can effectively neutralize the acid in tomato sauce. A quarter teaspoon per cup of sauce is a good starting point. Be aware it will cause the soup to fizz temporarily.
Incorporate Cream or Milk: While higher-fat dairy can be an issue for some, adding milk or powdered milk can buffer the acidity. This method is a secret of many Italian grandmothers for a smoother sauce.
Use Sweeter Ingredients: Adding sweeter, alkaline vegetables like carrots, beets, or pumpkin can naturally counteract the tartness of tomatoes. Pureeing roasted carrots or pumpkin into the soup base is an effective strategy.
Roast the Tomatoes: Roasting tomatoes can caramelize their sugars, enhancing sweetness and potentially mellowing out some of the harsher acidity.
Choose Lower-Acid Tomatoes: Opting for low-acid varieties like San Marzano or yellow tomatoes can make a difference, even if the pH is only slightly lower.

Comparison Table: Tomato Soup for Digestive Health


Feature	Conventional Tomato Soup	Modified Low-Acid Tomato Soup
Primary Ingredients	Canned tomatoes, heavy cream, garlic, onions, spices.	Low-acid tomatoes (fresh or canned), alkaline vegetables (carrots, pumpkin), powdered milk, baking soda.
Risk of Heartburn	High risk for sensitive individuals due to concentrated acidity and potential LES-relaxing ingredients.	Significantly reduced risk due to neutralizing and buffering ingredients.
Digestive Comfort	Can cause discomfort, bloating, and nausea in sensitive stomachs.	Easier to digest and less likely to cause irritation.
Flavor Profile	Often tart and rich, with a strong tomato flavor.	Sweeter and milder, with a more balanced flavor profile.
Nutritional Profile	Varies widely; can be high in fat and sodium, depending on preparation.	Can be lower in fat and sodium, while still providing antioxidants like lycopene.

Health Benefits of Tomatoes and Lycopene

Despite the potential for digestive upset, it is important to remember that tomatoes are a highly nutritious food. They are a rich source of vitamins A and C, potassium, and antioxidants, particularly lycopene. Lycopene is a powerful antioxidant that has been linked to numerous health benefits.

Heart Health: Lycopene and potassium found in tomatoes are associated with reducing the risk of heart disease.
Cancer Prevention: Lycopene may also play a role in cancer prevention, especially prostate cancer.
Skin and Eye Health: The vitamins and antioxidants in tomatoes promote healthy skin and vision.

For those who can tolerate it, a low-fat, low-sodium tomato soup can still be a nutritious part of a balanced diet. However, for anyone experiencing persistent digestive issues, consulting a healthcare professional is recommended. You can find more information about managing dietary triggers for GERD at Healthgrades.

Conclusion

While tomato soup can certainly increase acidity due to the natural acids found in tomatoes, this does not mean it is off-limits for everyone. For those prone to acid reflux, it is a significant trigger, often due to the concentrated acidity and other high-fat, high-spice ingredients. By understanding the mechanisms behind tomato-induced reflux and employing cooking techniques to neutralize the acid, many can continue to enjoy a milder version of this popular comfort food. Paying attention to individual tolerance is key, and simple adjustments can make a big difference in managing digestive health while still reaping the antioxidant benefits of tomatoes.

Frequently Asked Questions

For many people with acid reflux, tomato soup can be a trigger due to its high acidity. It can cause or worsen symptoms like heartburn. However, individual tolerance varies, and modifying the recipe with ingredients like baking soda or alkaline vegetables can help.

The pH of tomato soup typically falls within an acidic range, generally between 4.1 and 4.7, depending on the tomatoes and other ingredients used. This level is low enough to cause digestive issues for sensitive individuals.

Yes, adding milk or powdered milk can help reduce the acidity of tomato soup. Milk acts as a buffer and can neutralize the acids, leading to a smoother, less tart flavor that is easier on the stomach.

Good alternatives include soups made with low-acid vegetables like pumpkin, carrots, or red bell peppers. These can provide a similar flavor profile and creamy texture without the high acidity of tomatoes.

Canned tomato soup can sometimes be more acidic than homemade, as food processing companies often add extra citric acid for preservation. The ripeness of the tomatoes used in homemade soup can also affect its acidity.

If you experience heartburn, it's best to avoid adding ingredients that can worsen symptoms, such as heavy cream, excessive fat, garlic, onions, and spicy seasonings like chili.

Baking soda is a weak base (sodium bicarbonate) that reacts with the acid in tomatoes, causing a neutralization reaction. This process releases carbon dioxide, which causes fizzing, and results in a less acidic soup.