There's little evidence to suggest that excessive yawning is caused directly by a vitamin deficiency. However, some vitamin deficiencies may cause fatigue, which often involves yawning. Not getting enough vitamin B12, for example, can lead to vitamin B12-deficiency anemia, which may lead to feeling fatigued.

Excessive yawning can be related to the vagus nerve, which runs from the bottom of the brain down to the heart and stomach. In some cases, excessive yawning may indicate bleeding around the heart or even a heart attack. Other symptoms that may indicate a heart problem include: pain in the chest.