Vitamin B12 levels can be boosted by eating foods such as dairy, liver, salmon and eggs.
Ulcers around the mouth can be a sign of vitamin B12 deficiency, research suggests.
The small lesions around the mouth are sometimes known as canker sores.
They can also occur inside the mouth and may make eating painful.
Other, more common signs of vitamin B12 deficiency include feeling tired, experiencing muscle weakness and being constipated.
The conclusions about mouth ulcers come from a study including 58 people who had recurrent mouth ulcers.
Around half of the participants were given B12 supplementation and they were compared to a control group.
The results showed that three-quarters of people were free of ulcers after taking B12 and most saw a reduction in pain.
The authors explain the results:
“The average outbreak duration and the average number of ulcers per month decreased in both groups during the first four months of the trial.
However, the duration of outbreaks, the number of ulcers, and the level of pain were reduced significantly at five and six months of treatment with vitamin B12, regardless of initial vitamin B12 levels in the blood.
During the last month of treatment a significant number of participants in the intervention group reached ‘no aphthous ulcers status’”
Good dietary sources of vitamin B12 include fish, poultry, eggs and low-fat milk.
Fortified breakfast cereals also contain vitamin B12.
People who may have difficulty getting enough vitamin B12 include vegetarians, older people and those with some digestive disorders, such as Crohn’s disease.
Dr Ilia Volkov, the study’s first author, said:
“…the frequency of RAS [Recurrent Aphthous Stomatitis, or mouth ulcers] is as much as 25 percent in the general population, however, until now, there has been no optimal therapeutic approach.”
The study was published in The Journal of the American Board of Family Medicine (Volkov et al., 2009).