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.

9 comments for “Foods That Can Trigger Canker Sores

  1. sue
    November 3, 2013 at 9:02 pm

    My mouth sores are directly related to food sensitivities. Trident cinnamon gum causes an immediate ulceration. I am trying to find an ingredients list for the Olive Garden salad dressing as this also causes an immediate reaction. I am attempting to isolate the particular additives or ingredients that I have to stay away from and this is proving to be difficult to say the least. I also have other painful reactions to chemical additives and gluten such as hives, sinuses swelling shut, joint pain, muscle cramps and odd sensations. God help me, I just want to be normal but I will settle for knowing what I can eat and what I cannot.

    • January 21, 2014 at 7:49 am

      I tried a crushed baby aspirin with Alum directly on the ulcer. This is the only thing that relieved any of the pain at all. Do the aspirin first, crush and mix with a little water to make a paste. Put this on the ulcer with a q-tip. Wait until you notice the pain has subsided. Later on, put a little water on the end of a q-tip and dab it with a very very small amount of Alum. This can be found with the spices in the bakery aisle of your grocery store. Try not to swallow the Alum, tastes bitter. Just let in set on the ulcer. These are the only things that helped with a very painful ulcer under my tongue.

    • Nancy Ohman
      April 3, 2017 at 11:48 am

      Did you determine what in the Olive Garden Salad was causing you grief? Before I even got done eating my pasta I could feel the cold sore forming.

  2. Beverly
    February 4, 2014 at 1:42 pm

    I get the ulcers right under my dentures after eating strawberries. I thought that it was the seeds getting embedded in the gum. Now blueberries are doing the same thing. I get he sore then I can’t put my denture (lower, never tops) in for a week or more. SUCKS!! iLife strawberries and blueberries!

  3. Terry
    April 18, 2014 at 6:11 am


  4. Carl
    May 19, 2015 at 5:51 pm

    for me, peanuts and sunflower seeds will do it every time.

  5. Chris Domres
    June 12, 2016 at 5:32 am

    35 years ago a doctor treated me for Candida yeast infection in my bowel. I was put on a diet which was 1 part animal protein to 5 parts vegetables. I had to avoid all sugar, fruits, nuts, grains, alcohol. Withing three months I felt like a million bucks. I was on that diet for about 10 years, and had few cankers sores in that period. Before that I had canker sores every week. I now eat other foods but have to avoid strawberries, citrus fruits, salty nuts and chips, wheat, pineapple and tomatoes as those are my common canker sore triggers. Since these foods seem to be common triggers for many people, I wonder why no one has figured out what is actually happening in the body.

  6. MazTerGee
    July 2, 2017 at 11:42 am

    Iceberg lettuce, Apples and similar fruit does it for me.

  7. David
    December 11, 2017 at 6:18 am

    A 100% guarentee for me is Orange Juice. I can eat strawberriers, pineapple, hell just abaout anything else but as soon as i take the smallest sip of OJ i can feel one starti g to form.

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