Vitamin B12 is essential for the production of red blood cells and is important for the health of nerve cells and the formation of genetic material. The first symptoms of vitamin B12 deficiency are dizziness and fatigue. If left untreated, its deficiency can lead to anemia, damage to the nervous system, and other health problems.
Vitamin B12, also known as cobalamin, is a water-soluble vitamin found in certain foods such as meat, fish, dairy products, and eggs. Vegetables themselves are not a source of vitamin B12.
According to the New Zealand Adult Nutrition Survey, 8% of the population may be deficient in vitamin B12. Studies show that vitamin B12 deficiency is more common in women than in men.
Vitamin B12 deficiency is usually caused by a lack of an endogenous factor produced in the stomach to absorb vitamin B12 from food. Some people don’t produce enough endogenous factor, while others may have health problems that destroy it. Other causes of vitamin B12 deficiency include:
Do not eat foods rich in vitamin B12. This is especially true for vegans who do not consume animal products (meat, fish, milk, eggs, butter, cheese and other dairy products).
Digestive disorders such as gluten intolerance, inflammation of the stomach (gastritis), and problems with the pancreas can lead to inadequate absorption and utilization of B12.
Absorption is poor after gastric or intestinal surgery and in inflammatory bowel disease such as Crohn’s disease.
Medications that may interfere with the absorption of vitamin B12
A rare congenital problem.
Scientific studies have shown that genetic factors predispose some people to vitamin B12 deficiency.
Many of the early symptoms of vitamin B12 deficiency are related to anemia, when your body’s cells are not getting enough oxygen through the blood. Deficiency symptoms are:
If left untreated, vitamin B12 deficiency can slowly damage the nervous system, especially the nerves outside the brain and spinal cord. When the spinal cord is damaged, the first symptoms are difficulty feeling vibrations in the legs, loss of body position, and loss of muscle coordination (ataxia). Other symptoms of untreated vitamin B12 deficiency include:
Diseases of the heart and blood vessels
Spleen and liver enlargement
Mild depression and confusion
Hallucinations, personality and mood changes
Damage to the optic nerve.
After a diagnosis of vitamin B12 deficiency, a test that measures vitamin B12 absorption (Schilling’s test) can help determine the underlying condition and treatment options.
In most cases of vitamin B12 deficiency, vitamin B12 is injected into the muscle. These injections overcome the barrier to absorption of vitamin B12 from food. Initially, regular injections of 1000 mcg are given every week for 4-6 weeks. This frequency allows the body’s physiology to start producing red blood cells normally. It allows to increase the normal reserves of the liver.
Injections do not address the underlying cause of the deficiency, and depending on the underlying cause, B12 injections may need to be continued for life. A maintenance dose of 1,000 micrograms every three months is usually recommended.
Vegans are advised to take vitamin B12 supplements or nutritional yeast fortified with vitamin B12. In case of iron deficiency, oral iron supplements can be given.
Side effects of vitamin B12 supplements
Side effects of vitamin B12 are rare. Hypersensitivity (anaphylaxis) is very rare, and symptoms include swelling, itching, and irritation. Taking very high doses of vitamin B12 can sometimes cause acne. Other unusual side effects include skin rash, flushing, nausea, dizziness, and irregular heartbeat.
It is important to note that taking large amounts of vitamin C within an hour destroys vitamin B12. Absorption may also be reduced due to deficiencies in folic acid, iron, and vitamin E. Excessive consumption of nicotine and alcohol can lead to vitamin deficiency. B12 levels.
Vitamin B12 is better absorbed when taken with other B vitamins or calcium. Talk to your doctor about interactions with other medications you are taking.
Langan, R.K., Goodbred, A.J. (2017). Vitamin B12 deficiency: recognition and treatment. I am a family doctor. September 15, 2017; 96(6): 384-389.
Mayo Clinic (2017). Vitamin
Vitamin B12 Fact Sheet (Internet Age). Bethesda, MD: National Institutes of Health. https://ods.od.nih.gov/factsheets/VitaminB12-HealthProfessional/ [Retrieved: 06/19/19]
Department of Health, University of Otago. (2011). Focus on nutrition: key findings from the 2008/09 Dietary Survey of New Zealand Adults. Chapter 4. Nutrient Intake and Food Sources: Micronutrients. Wellington: New Zealand Department of Health. http://www.health.govt.nz/system/files/documents/publications/a-focus-on-nutrition-ch4_0.pdf
O’Toole, M.T. (Ed.) (2017). Vitamin B12 (cyanocobalamin) test. Mosby’s Dictionary of Medicine, Nursing, and Health Professions (10th ed.). St. Louis, MI: Elsevier.