Can Black Walnuts Cause Canker Sores?

Canker sores, small painful ulcers can occur anywhere in your mouth, making life miserable for several days. Apthous ulcers, the medical term for canker sores, can be confused with cold sores, but the two are not related. Canker sores often occur after eating certain foods; stress can also contribute to an outbreak of canker sores. Walnuts are among the foods best known as a potential source of canker sores, according to the Ultimate Dental Guide.

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A canker sore is a grayish ulceration with a yellow or white edge surrounded by a reddened area. The inside of the cheeks, tongue, roof of the mouth and inside of the lips are all common sites. Most last between 7 to 10 days and can occur in crops or one at a time. Most canker sores are small and heal without scarring, although more extensive canker sores can cause scarring.


Citrus foods, chocolate, cinnamon and all types of nuts, but particularly walnuts, pecans and macadamia nuts cause canker sores. English walnuts are especially likely to cause canker sores. You can’t catch canker sores from another person. Trauma, such as biting your cheek or tongue, can sometimes lead to a canker sore. Canker sores also occur as part of an immune response. Certain foods are likely to cause canker sores in susceptible persons.


L-Arginine, an amino acid, appears to increase cold sores caused by the herpes virus as well as canker sores in some people, according to Jonathon Wright, M.D. Walnuts have a high l-arginine content. An allergy to the substances in walnuts can also trigger canker sores.


If you get canker sores every time you eat black walnuts, pinning down the cause and coming up with a cure is fairly simple -- stop eating walnuts. If you have a canker sore in an area that’s interfering with eating, using an oral solution such as viscous lidocaine, which causes temporary numbness short-term, should give some relief. Severe outbreaks may respond to oral corticosteroids, which reduce inflammation. Tetracycline, an antibiotic made into a liquid suspension, can help heal the sore and decrease the discomfort. Brush your teeth carefully when you have a canker sore to avoid further irritation of the already painful area.