Take a diet rich in Vit B12 which should include meat and animal products, cheese, such as beef, liver, salmon, cod, and eggs. Take
B12 supplements
and breakfast cereals fortified with
vitamin B12. Finding the cause is important.
Other possibility is an acid reflux. Take Omeprazole empty stomach in morning and an antacid gel at bedtime. Refrain from smoking, alcohol, fuzzy drinks and spicy food. See if this helps.
Do discuss this with your doctor and get yourself examined. Take care!