Vitamin B12 is essential for nerve function, red blood cell production, and DNA synthesis — and low levels can show up as fatigue, brain fog, balance issues, numbness or tingling, and mood changes often written off as normal stress or aging.

plays such a big role in essential bodily functions, vitamin B12 deficiency can manifest itself in the following ways (5,6,7,8):

Anemia, megaloblastic anemia and pernicious anemia
Loss of balance and confusion
Numbness or tingling in the arms and legs
Weakness
Constipation, diarrhea, a loss of appetite, or gas

Nerve problems like numbness or tingling, muscle weakness, and problems walking
Vision loss
Mental health problems (including psychosis and depression)
Dementia
Alzheimer’s
Heart disease

Luckily, most of these symptoms can be reversed if promptly treated with proper B12 intake.