Functions
- red blood cell formation
- involved in synthesis of nucleic acids
Deficiency
- Pernicious anemia
Characteristics
- soluble in water or alcohol
- unstable in hot alkaline or acid solutions
Good Sources
Natural
- beef, pork, chicken
- liver, kidney
- milk and dairy products
- eggs
- most of vitamin required by humans is synthesized by intestinal bacteria
| Food | Quantity | mcg |
|---|---|---|
| Beef, lean braised flank | 3 oz | 2.81 |
| Chicken | 1/2 breast | 0.29 |
| Milk, non-fat | 1 cup | 0.93 |
| Egg | 1 large | 0.50 |
Artificial
- fortified cereals and soy products
Recommended Daily Allowances (RDA)
- Males (11 yrs. and older)
- 2.4 mcg
- 3 mcg
- Females (11 yrs. and older)
- 2.4 mcg
- 3 mcg
- Pregnant females
- 4 mcg
- Lactating females
- 5 mcg
- Children
- 2-5 mcg
- Infants
- 1-2 mcg
- Varied values reflect different references
Tolerable Upper Intake Levels (UL)
- Adults (19 to 50 yrs)
- not yet determined
Intakes above UL may lead to negative health consequences.
Supplementation
- Not usually necessary
- People who are on strict vegetarian diets may need supplementation.
- Some elderly people and those with certain food intolerances may be deficient in Vitamin B-12 because they lose their ability to absorb B-12 from foods.
- In which case, parenteral vitamin B-12 can be prescribed by a health care professional.
