Vitamin B12 deficiency is a treatable condition that happens if you are not consuming enough vitamin B12 in your diet or if your body is not absorbing it properly. Vitamin B12 deficiency can cause physical, neurological and psychological symptoms. It can be treated with vitamin B12 medications.
Vitamin B12 deficiency happens when your body is either not getting enough or not absorbing enough vitamin B12 from the food that you eat that it needs to function properly. Vitamin B12 is an important nutrient that helps your body make red blood cells and DNA, the genetic material in all of your cells.
Vitamin B12 deficiency can cause physical, neurological and psychological problems if it is not treated.
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Vitamin B12 is an important nutrient that helps your body keep your nerve cells and blood cells healthy. It also helps your body make DNA, the genetic material in all of your cells. Your body does not make vitamin B12 on its own, so you have to consume food and drinks that have vitamin B12 in order to get it. Vitamin B12 is found in animal products you eat and drink such as meat, dairy and eggs. It can also be found in fortified foods (foods that have certain vitamins and nutrients added to them) such as certain cereals, bread and nutritional yeast.
Adults need around 2.4 micrograms (mcg) of vitamin B12 a day, and people who are pregnant or breastfeeding need more. The amount of vitamin B12 babies and children need varies based on age.
There are two things that need to happen in order for your body to absorb vitamin B12 from the food you eat. First, hydrochloric acid in your stomach removes vitamin B12 from the food it was in. Next, vitamin B12 combines with something called intrinsic factor, a protein made by your stomach. Vitamin B12 is then able to be absorbed by your digestive system.
Some people have a rare condition called pernicious anemia, which means their stomach does not make intrinsic factor. Because of this, their body cannot properly absorb vitamin B12, which causes a vitamin B12 deficiency.
Vitamin B12 deficiency anemia happens when your body does not have enough healthy red blood cells because your body has a vitamin B12 deficiency. Vitamin B12 is needed to make red blood cells. Because of this, a lack of vitamin B12 can cause anemia. People can have a vitamin B12 deficiency without having anemia.
Any person can develop vitamin B12 deficiency at any age. People who are 60 years old or older are more likely to have vitamin B12 deficiency compared to other age groups.
Approximately 1.5% to 15% of people have vitamin B12 deficiency. Here are the percentages of people who have vitamin B12 deficiency based on age ranges:
Vitamin B12 deficiency happens if you are not eating enough vitamin B12 or your body is not absorbing the vitamin B12 you consume properly. Situations or conditions that can cause vitamin B12 deficiency include:
Vitamin B12 deficiency can cause physical, neurological and psychological symptoms. The symptoms of vitamin B12 deficiency can develop slowly and can get worse over time. Some people may have no symptoms despite having a low level of vitamin B12 in their bodies. People with vitamin B12 deficiency can have neurological symptoms and/or damage without anemia (lack of red blood cells).
General physical symptoms of vitamin B12 deficiency can include:
Neurological symptoms of vitamin B12 deficiency can include:
Psychological symptoms of vitamin B12 deficiency can include:
It can be difficult to diagnose vitamin B12 deficiency because symptoms are not always present or the symptoms can be similar to other nutritional deficiencies. Healthcare providers will usually do routine blood tests to check for vitamin B12 deficiency in people who have a high risk of developing it.
The tests used to diagnose vitamin B12 deficiency are a complete blood count (CBC) and a vitamin B12 blood test level. A person is diagnosed with vitamin B12 deficiency if the amount of vitamin B12 in their blood is less than 150 per mL.
Vitamin B12 deficiency can be treated with vitamin B12. It is often treated with cyanocobalamin, a man-made form of vitamin B12. Depending on the cause of the deficiency, the person may only have to be treated until their vitamin B12 levels are back to normal, or they may have to take vitamin B12 therapy for the rest of their life. Options for vitamin B12 treatment include:
A person is more likely to develop vitamin B12 deficiency if they have one or more of the following risk factors:
Most people can prevent vitamin B12 deficiency by consuming foods and drinks that have vitamin B12.
Options for consuming vitamin B12 include:
Other things you can do to help prevent vitamin B12 deficiency include:
The prognosis for people who have vitamin B12 deficiency depends on how early the deficiency is diagnosed and treated. If the vitamin B12 deficiency is caught early, most people are able to get rid of their symptoms with treatment. Depending on the cause of your vitamin B12 deficiency, you may have to only take medication for a short amount of time, or you may have to take medication for the rest of your life.
If vitamin B12 deficiency is left untreated, it can cause lasting serious side effects that affect the nervous system and brain. More severe side effects of vitamin B12 deficiency include:
Untreated vitamin B12 deficiency can lead to severe neurological (nervous system) damage, which can put an individual at a higher risk of mortality. Pernicious anemia, a deficiency in the production of red blood cells due to a lack of vitamin B12, can cause permanent neurological damage that can lead to death if it is untreated.
If you are experiencing symptoms of vitamin B12 deficiency or are at risk for developing vitamin B12 deficiency, contact your healthcare provider to see if you should take a blood test to measure your vitamin B12 level. If you have already been diagnosed with vitamin B12 deficiency and are experiencing new or concerning symptoms, be sure to reach out to your healthcare provider.
A note from Cleveland Clinic:
Vitamin B12 is an important vitamin that your body needs to be healthy. Most people can prevent vitamin B12 deficiency by consuming enough of it in their diet. If you have risk factors for developing vitamin B12 deficiency or are experiencing symptoms, be sure to contact your doctor to get a blood test to check your levels.
Last reviewed by a Cleveland Clinic medical professional on 04/25/2022.
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