10 Things You Need to Know About B12

4. Deficiencies are Serious

Since we need B12 for many functions in the body, a deficiency is not something to take lightly. The National Institute of Health (NIH) estimates that 1.5% to 15% of Americans are deficient in vitamin B12. Early symptoms of B12 deficiency are numbness and a pins and needles sensation known as paresthesia. People may also experience problems with balance, tiredness, joint pain, weakness, constipation, mood swings, lack of appetite, unexplained weight loss, poor memory, and megaloblastic anemia. Additionally, approximately 50% of patients with a deficiency begin to exhibit the symptoms while their lab values still show normal B12 levels -- various interactions can mask deficiencies.