What is the possible reason for frequent mouth ulcers in kids? my kid is 8.5 yr old.

A. hi mainly two reasons first , constipation or second is deficiency of vitamin b12 ,vitamin D 3 , folic and zinc so ,first ,i advise to give homemade food items which consist of curd ,green veggies ,fresh fruits more second ,i advise to provide sunlight atleast 20 minutes a day. give less spicy ,soft food items which makes easy to eat.