Prairie Naturals new sublingual Vitamin B-12 5000 mcg (methylcobalamine) is readily absorbed in a tasty little tablet that melts rapidly & thoroughly under the tongue. From Dr Oz to the Mayo Clinic, every health expert is recommending the daily intake of Vitamin B-12. (*) A vitamin B-12 deficiency can cause permanent nerve damage, resulting in numbness and tingling in the hands and feet, and balance problems. Deficiency can also cause anemia, depression, confusion, poor memory and dementia. Concerns have also been raised about the apparent link between low levels of B-12 and an increase in homocysteine, an amino acid that can cause problems within your coronary arteries.