A canker sore is a type of ulcer that occurs on the soft tissues in the oral cavity. They aren’t contagious and are harmless, but if you’ve had a canker sore before, you know how uncomfortable they can be. Although experts aren’t sure of the exact cause of canker sores, there are certain events that can trigger them, such as stress or even an injury to the mouth.

Some people who have oral appliances such as braces or dentures experience these mouth sores. But can certain foods cause canker sores? Here are a few foods that may trigger these mouth ulcers or increase your risk for them!

Citrus Fruits

Citrus fruits are very acidic and, for some, can trigger canker sores [1]. These include fruits such as lemons, oranges, and grapefruit, but there are other acidic fruits that may cause or worsen canker sores. These include pineapples, strawberries, apples, and tomatoes.

If you have an existing canker sore, eating any of these or other acidic fruits can cause more discomfort, so it’s best to avoid them if possible until your canker sore is healed. The acid present in these fruits can prolong the healing of canker sores, since it’s essentially an open wound.

Foods You May Be Sensitive to

For others, food allergies or sensitivities could be a potential cause of canker sores. Researchers aren’t sure why this is, but it may have to do with your immune system’s response to these foods you may be sensitive to [2]. These foods could include:

• Chocolate
• Coffee
• Dairy
• Eggs
• Gluten
• Nuts
• Spicy foods

Not every person will experience canker sores from these foods, of course, and triggers can be different for everyone. These are just some of the most common foods and drinks that may cause sensitivities in people and lead to canker sores.

Healing Canker Sores

Canker sores can take up to two weeks to fully heal. While your canker sore is healing, avoiding your trigger foods may help, especially foods with citric acid. Avoiding hot, spicy, or sweet foods can help too [3]. It’s also a good idea to avoid alcohol and carbonated beverages, as these can aggravate canker sores and cause additional inflammation and discomfort. Instead, focus on bland foods, and cold foods and drinks can help ease your discomfort as well.

To help accelerate healing of your canker sore, you can try rinsing with salt water (about one teaspoon in a half a cup of warm water) every few hours. Other research shows that zinc and vitamin B supplements may help ease canker sore outbreaks [4].

If your canker sore is excessively painful, large, or you have several sores at once, it’s time to see your dentist. He or she may recommend further testing to ensure there’s not an underlying health issue contributing to the sores, or may be able to recommend a prescription or over-the-counter ointment to help heal your canker sores.

Do you know of any foods that seem to cause your canker sores? If so, you may be sensitive to these foods, or you may need to consume less of them to control your canker sore outbreaks. If you frequently experience canker sores, don’t hesitate to follow up with your doctor or dentist for help!

Sources:
1. https://my.clevelandclinic.org/health/diseases/10945-canker-sores
2. https://www.mayoclinic.org/diseases-conditions/canker-sore/symptoms-causes/syc-
3. https://wa.kaiserpermanente.org/kbase/topic.jhtml?docId=zd1065
4. https://www.jabfm.org/content/22/1/9