From the Guidelines
Vitamin B12 should be supplemented immediately in individuals with deficiency, and routine supplementation is recommended for those at high risk, such as patients undergoing bariatric surgery, with a frequency of every 2-3 months lifelong 1.
Key Recommendations
- For people with neurological involvement, administer hydroxocobalamin 1 mg intramuscularly on alternate days until there is no further improvement, then administer hydroxocobalamin 1 mg intramuscularly every 2 months 1.
- For people with no neurological involvement, administer hydroxocobalamin 1 mg intramuscularly three times a week for 2 weeks 1.
- Following bariatric surgery, recommend routine supplementation with vitamin B12 intramuscular injections every 3 months 1.
Important Considerations
- Vitamin B12 deficiency can cause anemia, neurological problems, and cognitive issues, and supplementation is essential to prevent these complications.
- The typical dose for maintenance is 1 mg intramuscularly every 2-3 months lifelong 1.
- It is crucial to seek urgent specialist advice from a neurologist and hematologist if there is possible neurological involvement, such as unexplained sensory and/or motor and gait symptoms 1.
From the FDA Drug Label
A vegetarian diet which contains no animal products (including milk products or eggs) does not supply any vitamin B12. Patients following such a diet, should be advised to take oral vitamin B12 regularly The need for vitamin B12 is increased by pregnancy and lactation. Deficiency has been recognized in infants of vegetarian mothers who were breast fed, even though the mothers had no symptoms of deficiency at the time. Patients with pernicious anemia should be informed that they will require monthly injections of vitamin B12 for the remainder of their lives.
Vitamin B12 supplementation is recommended in the following situations:
- Patients with pernicious anemia, who will require monthly injections of vitamin B12 for the remainder of their lives 2
- Patients following a vegetarian diet with no animal products, who should take oral vitamin B12 regularly 2 3
- Pregnant and lactating women, who have an increased need for vitamin B12 2 3
- Infants of vegetarian mothers who were breast fed, to prevent deficiency 2
- Children, who should intake vitamin B12 in the amount (0.5 to 3 mcg daily) recommended by the Food and Nutrition Board, National Academy of Science-National Research Council 2 3
From the Research
Vitamin B12 Supplementation
Vitamin B12 supplementation is necessary for individuals with a deficiency or at risk of deficiency. The following groups may require supplementation:
- Patients with gastric or small intestine resections, inflammatory bowel disease, or those taking certain medications such as metformin or proton pump inhibitors for an extended period 4
- Vegans or strict vegetarians, as they do not consume animal-derived foods that are natural sources of vitamin B12 4, 5
- Adults older than 75 years, as absorption rates decline with age 4
- Patients who have had bariatric surgery, as they may have impaired absorption 4
Supplementation Dosage and Route
The dosage and route of supplementation depend on the individual's condition and deficiency severity:
- Oral administration of high-dose vitamin B12 (1 to 2 mg daily) is effective for correcting anemia and neurologic symptoms 4, 6
- Intramuscular therapy may be necessary for patients with severe deficiency or severe neurologic symptoms, as it leads to more rapid improvement 4
- High-dose oral vitamin B12 at 1000 μg daily can replace vitamin B12 levels in patients with pernicious anemia 6
High-Risk Groups
Certain groups are at higher risk of vitamin B12 deficiency and may require prophylactic supplementation:
- Infants, children, adolescents, and women of reproductive age in populations with restricted dietary intake of animal-derived foods 5
- Elderly individuals, as they are more likely to have impaired absorption or dietary deficiencies 4, 5
- Patients with a history of diseases or medications that impair vitamin B12 absorption 4, 7