Vitamin B12 is an essential water-soluble vitamin that is commonly found in a variety of animal foods such as fish, shellfish, meat and dairy products. Synthetic vitamin B12 is frequently used in combination with other B vitamins in vitamin B complex formulations and added to supplements and fortified foods such as cereals. An adequate supply of vitamin B12 is essential to maintain healthy nerve cell and red blood cell function, as well as for folate utilization. The average fractional absorption of vitamin B12 from food by healthy individuals is approximately 50 percent 1.
No adverse effects have been associated with vitamin B12 intake from food or supplements in healthy individuals 1. The U.S. Food and Drug Administration (FDA) has established a Reference Daily Intake (RDI) of 6 μg vitamin B12 for adults and children 4 or more years of age (21CFR101.9). RDIs are a set of dietary references for essential vitamins and minerals that are considered amounts sufficient to meet the daily requirements of healthy individuals. RDIs serve as the basis for calculating the percent daily value (%DV) amounts found on dietary supplement and food labels.