 Hematinic deficiencies ( vitamin B12 , folic acid and iron ) , occurring singly or in combination , and with or without any underlying gastrointestinal disease , may be twice as common in people with RAS . However , iron and vitamin supplements only infrequently improve the ulceration . The relationship to vitamin B12 deficiency has been the subject of many studies . Although these studies found that 0 – 42 % of those with recurrent ulcers suffer from vitamin B12 deficiency , an association with deficiency is rare . Even in the absence of deficiency , vitamin B12 supplementation may be helpful due to unclear mechanisms . Hematinic deficiencies can cause anemia , which is also associated with aphthous @-@ like ulceration . 
