Canker Sores in the Mouth Are a Warning Sign of Folate Deficiency.
A canker sore is a small, painful ulcer inside the mouth that results from folate deficiency. The sores are white- or yellow-colored with a swollen red border and are usually found inside the cheeks or lips, on or under the tongue, or on the gums. People usually feel pain, tingling, or burning in their mouth before the sore appears. In addition to general discomfort, canker sores can also cause fever and swollen lymph nodes. The sores usually heal on their own but can cause severe pain and other serious complications.
Diets that are low in folate and other B vitamins make you more vulnerable to canker sores, as do medical conditions that interfere with the absorption of folate. If you’re prone to canker sores, you can increase folate intake through your diet or through folic acid supplements. Taking folate B12 may also be necessary to prevent or reduce canker sores.