Function: • It has a role in folate metabolism by modifying folate coenzymes to active forms to support metabolic functions, including the synthesis of DNA and RNA. • It is required for the metabolism of fatty acids and amino acids. • It helps develop and maintain the myelin sheaths that surrounds and protect the nerve fibers. RDA: 1-2 mcg/day • Toxicity: none reported. • Both Vitamin and the intrinsic factor must be present for absorption.