B12 deficiency can cause megaloblastic anemia, a condition in which abnormal red blood cells are produced.
Possible signs include pale skin, weakness, tiredness, and heart palpitations.
Palpitations can also have many unrelated causes, so recurring or concerning episodes should be medically assessed.
6. A Sore or Red Tongue
Changes inside the mouth can occasionally provide another clue.
Vitamin B12 deficiency may cause glossitis, in which the tongue becomes sore, inflamed, or unusually red. Mouth soreness can also occur.
Because these symptoms can result from many conditions, they are most meaningful when they occur alongside other signs of deficiency.
7. Loss of Appetite or Unexplained Weight Loss
