Vitamin B12 is an essential nutrient that can be found in many food products, particularly animal products like eggs, dairy, meat and shellfish. Vitamin B12 is considered an essential vitamin because it's able to help the body create red blood cells, produce cellular energy and synthesize DNA.
Although most people need just a few micrograms of vitamin B12 per day, larger amounts of up to 1,000 micrograms may be required to help people with certain medical conditions.
Vitamin B12 Deficiency
The typical vitamin B12 dosage for adults is 2.4 micrograms per day. Too little of this vitamin will result in a deficiency. Vitamin B12 deficiency can lead to issues with balance, memory and soreness of the mouth or tongue. People who are vitamin B12 deficient may also experience confusion, depression or anemia. Low levels of vitamin B12 in women may cause menstrual disturbances or result in the complete absence of menstruation.
Vitamin B12 deficiency can occur when there's a lack of this nutrient in the foods you're eating. Because vitamin B12 is found in high amounts in animal products, people who are vegan or vegetarian or who avoid meat products are at increased risk for vitamin B12 deficiencies. Vegans are at the highest risk, as their main source of vitamin B12 may be cereals or other grains fortified with this vitamin.
If you have pernicious anemia, you'll have more trouble creating new blood cells and will require vitamin B12 supplementation. Lifelong vitamin B12 supplements may be required at doses between 100 and 1,000 micrograms. As such, "B12 vitamin 1,000 mcg" refers to a high dose (1,000 micrograms) of vitamin B12 suitable for someone with nutrient absorption issues or pernicious anemia.
Vitamin B12 Supplements
High doses of vitamin B12 have been clinically recommended for many years. Recent research, including a 2018 study in the Cochrane Database of Systematic Reviews and a 2017 study in the American Family Physician Journal showed that doses between 1,000 and 2,000 micrograms are safe and effective ways to treat symptoms of vitamin B12 deficiency, including anemia and neurologic symptoms. Although these supplements may seem excessive, only a small amount is typically taken up by your body; the rest is excreted in your urine.
Certain people, such as vegans, vegetarians, people over age 50 and pregnant women, should consider taking vitamin B12 supplements. If you believe you're vitamin B12 deficient, you should consult your doctor before starting any supplements so you don’t take too much. You may also want to consider eating more foods that are rich in vitamin B12, like fortified cereals and plant-based milk products, or natural sources of vitamin B12, like eggs, fish and meat.
- National Institutes of Health: Office of Dietary Supplements: Vitamin B12
- MedlinePlus: B Vitamins
- The American Journal of Clinical Nutrition: Human Dietary Deficiency of Vitamin B12
- Nutrients: Vitamin B12 in Health and Disease
- Journal of Human Nutrition and Dietetics: Avoidance of Meat and Poultry Decreases Intakes of Omega-3 Fatty Acids, Vitamin B12, Selenium and Zinc in Young Women
- Harvard Health Publishing: Getting Enough Vitamin B12
- Journal of Blood Medicine: Optimal Management of Pernicious Anemia
- Journal of Internal Medicine: Oral Treatment of Pernicious Anemia With High Doses of Vitamin B12 Without Intrinsic Factor
- Cochrane Database of Systematic Reviews: Oral Vitamin B12 Versus Intramuscular Vitamin B12 for Vitamin B12 Deficiency
- American Family Physician: Vitamin B12 Deficiency: Recognition and Management