6. Mouth Ulcers
A perhaps surprising symptom of B12 deficiency is the formation of mouth ulcers. The exact reason for this connection is not fully understood, but may be to do with damage to the nerves resulting in inflammation.
Mouth ulcers can also be a general sign of being run down and stressed, which of course can result from poor production of key nutrients. When you experience mouth ulcers, you can try using marmite in order to address the problem or using gels designed to combat them. Also important is to fortify your immune system, get rest, and avoid stress!