Mouth Symptoms. Vitamin B12 deficiency can cause burning mouth syndrome, with symptoms such as dry mouth, increased thirst, sore mouth, taste loss or changes, tingling or numb sensations and burning sensations in the tongue, lips, gums, palate, throat or entire mouth.itamin B12 Deficiency. Poor nutrition or inadequate intake of vitamin B12 can cause B12 deficiency. Vitamin B12 food sources include animal products such as meat, poultry, fish, clams, oysters, eggs and dairy products.