Symptoms:

Sore tongue that may have fissures, cracks and sores at mouth edges.

Deficient: Vitamin B.
Since deficiency in vitamins B2 (riboflavin), B3 (niacin), B6 and B12 produce the similar symptoms of cracked and sore tongue and at the mouth edges, it is difficult to figure out if you are deficient in just one or more than one of these vitamins. Hence, it will be helpful to take multi-vitamin B supplements. Also, do include vitamin B-rich sources such as chicken meat, eggs, shellfish and milk in your diet.

Symptoms:

Bleeding gums, yeast infections, lowered immune response, impaired taste.

Deficient: Vitamin C or A.
Deficiency in vitamin C can cause the gums to bleed and the body's immune system to weaken, leading to infections such as yeast infection of the mouth and common cold. Eat more spinach, broccoli, red peppers, papaya, mango, kiwi, kale and other green leafy vegetables.