Foods That Can Trigger Canker Sores


Did you know the mere act of eating can trigger a canker sore in some people? Also called recurrent aphthous stomatitis, these small flat ulcers are extremely tender and often trigger a big jolt of pain when eating or drinking. Unfortunately, for some people the foods they eat will actually cause them to develop a mouth sore.

Acidic Foods

The acidity of orange juice is a common trigger of canker soresWhile there can be many possible causes – and the exact mechanism still isn’t fully known – eating certain types of foods and drinks can set off an outbreak. One of the main culprits is acidic foods, most commonly orange juice.  The introduction of an acidic food can cause minor tissue damage which is just enough of an upset to set off sores in people who are prone to them. Tomatoes, citrus fruits  and pineapples are other acidic foods that frequently cause this reaction. Sadly for many of us, coffee and chocolate are also high on the acid scale and can irritate the oral cavity of some people as well.

Other Culprits

people sensitive to wheat may be subject to mouth ulcers

Gluten sensitivities may contribute to mouth sores. Gluten is found in wheat, barley and rye products.

People with certain food sensitivities, not necessarily full-blown allergies, may also find they get frequent mouth sores when they eat certain things, most commonly shellfish and nuts, especially walnuts. There are also quite a few people who have unrecognized sensitivities to gluten, found in grains such as wheat, barley and rye, that may cause them to get outbreaks. In fact, people with Celiac Disease, which is an intolerance of gluten, often experience mouth ulcers as a symptom of their disease if they ingest a gluten-containing food.

Even if you don’t have a food allergy or intolerance, simply eating something with jagged edges such as a potato chip, tortilla chip or a cracker could promote a canker sore. The sharp edges can create microscopic tears or scrapes inside your mouth, leaving it susceptible to the formation of an ulcer.

Avoiding Acidic Foods

If you are prone to mouth ulcers, you should avoid acidic foods. No surprise if you read the above. It may surprise you  to learn that these include many canned and processed foods because manufacturers add ingredients that acidify them in order to prevent the growth of bacteria and extend the shelf life. In addition, especially when you have an open sore, you should avoid salad dressings that contain vinegar, fruit juices, pickles, jams and jellies, sodas and energy drinks as these all have a high pH, meaning they have a high level of acidity.

Fruits to Avoid

strawberries may be too acidic for some peopleThere are also a variety of fruits that may create a problem for some people, particularly berries. These would include strawberries in particular, as well as raspberries and blackberries. Cherries, pomegranate and cranberries are others to avoid, in addition to citrus fruits including oranges, limes, lemons and grapefruit.

Eat Yogurt

Beneficial foods to eat include yogurt in particular. The best choice is plain yogurt containing live lactobacillus acidophilus, which is “good bacteria,” also known as a probiotic. Yogurt helps maintain the proper balance of good bacteria vs bad in your intestinal tract and some people find that eating yogurt on a daily basis can actually help prevent them from getting mouth sores. Usually about four tablespoons per day is suggested for a preventative, and if you have an active ulcer eating a cup of plain yogurt a day until the sore heals can be very helpful. Plus the coolness of the yogurt is soothing.

Keep a Food Log

If you think you are getting mouth sores because of the foods you eat, try keeping a food diary to see if you can discover the triggers. List the types of foods you eat as well as the quantities and be consistent, even during times when you do not have an outbreak. Then if you get a canker sore you can look back on your food log and you may be able to pinpoint the offending food or beverage.

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