What canker sore Food sensitivities, particularly to chocolate, coffee, strawberries, eggs, nuts, cheese, and spicy or acidic foods. A diet lacking in vitamin B-12, zinc, folate (folic acid) or iron. An allergic response to certain bacteria in your mouth. Helicobacter pylori, the same bacteria that cause canker sore.
It has been noted in several studies that canker sores are either caused or triggered further when there is a deficiency of folic acid, zinc, or iron in the human body. Deficiencies of calcium can also cause canker sore on tongue, but more than causing them, calcium deficiency can worsen the situation.