Vitamin B12 and IBD

Vitamin B12 is used by the body for several different purposes. Our bodies need vitamin B12 to function properly and especially to make more red blood cells. Some of the things vitamin B12 does include:

  • regulating metabolism
  • maintenance of the central nervous system
  • creation of red blood cells
Duck liver mousse on crustini
Thomas Barwick / Getty Images

What Is Vitamin B12?

Vitamin B12 is one of the water-soluble vitamins and is excreted in urine if it is not used by the body. Vitamin B12 is stored in the liver. A lack of B12 can leave the body unable to make more red blood cells, which can result in symptoms such as weakness, tingling in the arms and legs, or a condition called pernicious anemia.

Vitamin B12 is absorbed in the small intestine, and people who have had surgery to remove sections of the small intestine (such as those with Crohn's disease) may not be able to absorb enough B12. A lack of vitamin B12 is treated by supplementation, such as by receiving B12 shots on a regular basis.

Who Is at Risk For Low Vitamin B12?

Vitamin B12 is absorbed in the small intestine.Conditions that affect the small intestine could result in lower amounts of vitamin B12 being absorbed. This includes Crohn's disease and celiac disease. This could also occur with people who have for people who can't absorb enough vitamin B12 in the intestine, an injection of B12 might be needed.


Vitamin B12 is present in some foods and is also available as a supplement. The supplement can be bought over-the-counter as a capsule, a sublingual tablet (that's put under the tongue, and a liquid. It is also available as an injection, which is prescribed by a physician and, in most cases, given as a shot in the office. In some cases, certain patients are given the B12 injections to give to themselves at home.

Supplementing with B12 isn't necessary for most healthy people, but some people with IBD or other digestive conditions may find a need for supplements. In most cases, the deficiency is found during a blood test. A physician will then recommend a supplement, which could be an over-the-counter supplement or an injection, or a combination of the two. In some cases, supplementation daily or weekly is done until levels rise, and then supplementation is done on a less frequent basis.

Food Sources 

For those who need supplements, food might not provide enough B12. However, most people are able to get their vitamin B12 needs to be met through foods. Food sources of vitamin B12 include:

  • Eggs
  • Meat (especially organ meats such as liver)
  • Poultry
  • Shellfish
  • Milk
  • Fortified breakfast cereals

Vitamin B12 from animal sources (meats, eggs, milk) is easier for the body to use. Vegetarians and vegans that don't require supplementation can typically get enough vitamin B12 from eating a fortified breakfast cereal.

Recommended Daily Amount 

The recommended daily amounts of vitamin B12, in micrograms, are:

  • Infants aged 0 - 6 months: 0.4 mcg
  • Infants aged 7 - 12 months: 0.5 mcg
  • Children aged 1 - 3 years: 0.9 mcg
  • Children aged 4 - 8 years: 1.2 mcg
  • Children aged 9 - 13 years: 1.8 mcg
  • Men and women aged 14 years and older: 2.4 mcg

A Word From Verywell

Vitamin B12 is important to overall health and some people with IBD, especially those who have had surgery on their small intestine, may be absorbing less than they need. Fortunately, for most people, supplementing on a regular basis will help bring the vitamin B12 level back up and start to reverse the effects of the deficiency. Supplements are available in liquid form that is easy to take every day and might be better absorbed than the B12 found in food sources. Some people might need B12 shots for a short period of time and others may need it on a more long-term basis. In some cases, shots can be given at home either doing it yourself or with the help of a friend or family member. 

9 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Lyon P, Strippoli V, Fang B, Cimmino L. B vitamins and one-carbon metabolism: implications in human health and disease. Nutrients. 2020;12(9):2867. doi: 10.3390/nu12092867

  2. Serin HM, Arslan EA. Neurological symptoms of vitamin b12 deficiency: analysis of pediatric patients. Acta clinica Croatica. 2019;58.(2.):295-301. doi: 10.20471/acc.2019.58.02.13

  3. Krzywański J, Mikulski T, Pokrywka A, et al. Vitamin b12 status and optimal range for hemoglobin formation in elite athletes. Nutrients. 2020;12(4):1038. doi: 10.3390/nu12041038

  4. National Heart, Lung, and Blood Institute. Vitamin B12-Deficiency Anemia.

  5. Ward MG, Kariyawasam VC, Mogan SB, et al. Prevalence and risk factors for functional vitamin b12 deficiency in patients with crohnʼs disease: Inflammatory Bowel Diseases. 2015;21(12):2839-2847. doi: 10.1097/MIB.0000000000000559

  6. Wang H, Li L, Qin LL, Song Y, Vidal-Alaball J, Liu TH. Oral vitamin B12 versus intramuscular vitamin B12 for vitamin B12 deficiency. Cochrane Database Syst Rev. 2018;3:CD004655. doi: 10.1002/14651858.CD004655.pub3

  7. Langan RC, Goodbred AJ. Vitamin b12 deficiency: recognition and management. Am Fam Physician. 2017;96(6):384-389. PMID: PMID: 28925645

  8. National Library of Medicine MedlinePlus. Vitamin B12.

  9. MacFarlane AJ, Shi Y, Greene-Finestone LS. High-dose compared with low-dose vitamin b-12 supplement use is not associated with higher vitamin b-12 status in children, adolescents, and older adults. The Journal of Nutrition. 2014;144(6):915-920. doi: 10.3945/jn.113.190256

Additional Reading

By Amber J. Tresca
Amber J. Tresca is a freelance writer and speaker who covers digestive conditions, including IBD. She was diagnosed with ulcerative colitis at age 16.