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Guide to Canker Sore Prevention   ( Home | Diet | Foods | Recipes )

Canker Sores & Diet: 5 Tips for Preventing Mouth Ulcers With Diet

Diet Tips for Preventing Canker Sores

The link between canker sores and diet is well-established. We know that certain dietary habits – such as eating acidic or other irritating foods – can cause canker sores, while other eating habits may help prevent outbreaks of these non-contagious mouth ulcers. In this section of's Canker Sore Guide, you will learn five excellent dietary tips that can help prevent canker sores from forming inside of your mouth.

#1: Step Up Your Intake of Vitamin B12 and Vitamin B9

Vitamin B12 (cobalamin) has been shown to be effective at treating canker sores. In one study, 58 people suffering from canker sores received either a dose of 1,000 mcg of vitamin B12 or a placebo. The number of ulcers, the duration of outbreaks as well as the level of pain associated with the sores decreased significantly after 5 months of treatment in the group who were given vitamin B12. Furthermore, 74% of patients in this group (in contrast to 32% in the control group) reported no canker sores at the end of the study. Also vitamin B9, better known as folic acid, appears to have properties that may help prevent canker sores, particularly in people who are deficient in this important vitamin.

#2: Cut Down on Alcohol

Another very good diet tip for preventing canker sores is to limit alcohol consumption. Excessive alcohol use can seriously deplete the stores of B vitamins, including vitamin B9 and vitamin B12, which have been shown to prevent canker sores.

Iron in foods like spinach may help prevent canker sores.

#3: Eat Foods Rich in Iron

An iron deficiency, which is the most common form of nutritional deficiency in Western countries, has been associated with recurrent canker sores. Women who are menstruating (especially if they have heavy periods), women who are pregnant or have just given birth, long-distance runners, and vegans have a particularly high risk of being deficient in iron. To prevent canker sores that may be linked to an insufficient dietary intake of iron and/or an iron deficiency, add more iron-rich foods such as dried fruits, egg yolks, liver, lean red meat, oysters, poultry, salmon, spinach, tuna and whole grains to your anti-canker sore diet.

#4: Eliminate Food Allergens

Food allergies and intolerances are believed to be the primary cause of canker sores, and therefore, elimination of food allergens may be the best dietary tip for people who suffer from recurrent canker sores. It is important to keep in mind, however, that what causes an allergic reaction, such as a canker sore outbreak, in one person may not trigger the same reaction in another person. That said, some foods have been shown to be more likely to cause allergic reactions than others. These foods include dairy, eggs, soy products, yeast, and wheat.

Other common allergens that people with recurrent canker sores may be sensitive to include certain food additives and preservatives such sulfites, tartrazine, benzoates, and monosodium glutamate (MSG). Benzoates are anti-microbial preservatives that are commonly used in soft drinks but also in other foodstuffs. Tartrazine is one of the most widely used artificial food colorings, and it is found in many processed foods in varying proportions. Products that may contain tartrazine include yellow or orange-colored soft drinks, confectionery, candy, chips, cereals, instant soups, some rice and pasta brands, sauces, canned vegetables, cheeses, butter, and pickled products. Monosodium glutamate, perhaps better known by the abbreviation "MSG", is a flavor enhancer used in many processed foods as well as in food prepared in Chinese restaurants. Sulfites are commonly added to dried fruits and alcoholic beverage in order to extent their shelf life. The best way to make sure your anti-canker sore diet is free of additives and preservatives is to opt for natural, organic foods that have gone through minimal processing.

You can have an allergy test performed at an allergy clinic to find out whether you are allergic to certain substances in your diet. An alternative way to go about identifying potential allergens is to complete an elimination diet under the supervision of a nutritionist. This diet involves removing foods and substances that are suspected of causing allergic reactions, such as canker sore outbreaks, for a period of two to four weeks.

If, after the elimination period, symptoms have cleared or improved significantly, the suspected foods and substances can be re-introduced to the diet, one food or substance at a time (the so-called "challenge" phase of the elimination diet). During this phase, the dieter systematically goes through all the suspected allergens, one by one, by consuming a suspect food or substance several times a day and then returning to the elimination diet for a few days. If symptoms re-occur or worsen during these days, the dieter may be allergic to the food or chemical that was re-introduced. Although an elimination diet is fairly simple to complete, the whole process can take several months.

#5: Avoid Acidic and Spicy Foods

If you are prone to getting canker sores, you might benefit from avoiding acidic or spicy foods. These foods may irritate your mouth, triggering the development of canker sores.

Further Reading (Offline)
Food Intolerance Bible UK's leading nutritionist Antony J. Haynes has distilled his knowledge into a comprehensive guide designed to tackle health problems caused by food intolerances. The Food Intolerance Bible provides answers to questions like: How healthy is your intestinal ecology? Which foods are likely to cause food intolerance symptoms such as bloating, cramping, rashes, mood swings and chronic fatigue? How to identify and eliminate culprit foods? Which supplements work for which symptoms? To order a copy of Haynes' book, head to or
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