Patient education: Vitamin B12 deficiency and folate (folic acid) deficiency (The Basics)
Written by the doctors and editors at UpToDate
What are vitamin B12 deficiency and folic acid deficiency?
— Vitamin B12 and folic acid (also called “folate” or “vitamin B9”) are 2 different vitamins that your body needs to work normally. A “deficiency” means that your body does not have as much of something as it needs.
People can have vitamin B12 deficiency, folic acid deficiency, or both.
Why are vitamin B12 and folic acid important?
— Your body needs vitamin B12 for many things. For example, you need vitamin B12 to make new blood cells, such as red blood cells, and for your nervous system to work normally.
Your body needs folic acid, too, to make new cells. Folic acid is especially important for women who are planning to get pregnant (or might get pregnant). That’s because folic acid is needed, especially during the first few weeks of pregnancy, for a baby to develop normally. Folic acid is needed for the spinal cord to develop correctly.
What causes vitamin B12 deficiency or folic acid deficiency?
— People can get vitamin B12 or folic acid deficiency when:
●They don’t eat enough foods that have the vitamin in them – This is more common in the case of folic acid, which is found in plants. It can also be the cause of vitamin B12 deficiency for people who eat a vegetarian diet and do not take extra vitamin B12. (Vitamin B12 is found in meats and animal products like eggs.)
●They eat foods with vitamin B12 and folic acid, but their body can’t absorb or use the vitamins normally – These things can happen with certain medical problems or as a side effect of certain medicines. This is more common in the case of vitamin B12.
What are the symptoms of vitamin B12 deficiency and folic acid deficiency?
— A deficiency of vitamin B12, folic acid, or both can cause anemia. Anemia is the term doctors use when a person has too few red blood cells. Anemia can cause headaches or trouble breathing, especially with exercise. It can also make people feel tired or weak.
Vitamin B12 deficiency can also cause other symptoms, including:
●Tingling or numbness in the hands or feet
●Trouble walking
●Mood changes
●Memory problems or trouble thinking clearly
Should I see a doctor?
— Yes. You should see your doctor if you have any of the symptoms listed above.
Is there a test for vitamin B12 deficiency and folic acid deficiency?
— Yes. Your doctor can do blood tests to check for deficiencies of these vitamins.
If you have vitamin B12 or folic acid deficiency, your doctor will want to know why. He or she might do other tests to find out if it’s because of a medical condition or a problem with your diet.
How are vitamin B12 deficiency and folic acid deficiency treated?
— Doctors treat vitamin B12 deficiency by giving people vitamin B12. The treatment comes as a shot, as pills. Most people with vitamin B12 deficiency need vitamin B12 shots, especially at first. Later, some people can switch to taking vitamin B12 pills instead of getting shots.
Doctors treat folic acid deficiency by giving people folic acid. This treatment comes as a pill. Women who are pregnant or planning to get pregnant should also make sure they are getting enough folic acid.
Your doctor will also treat the cause of your deficiency, if it can be treated.
Can vitamin B12 deficiency and folic acid deficiency be prevented?
— Yes. You can lower your chances of getting vitamin B12 deficiency and folic acid deficiency by eating foods that have the vitamins in them. Foods with vitamin B12 include all kinds of meat, fish, and animal products like eggs and milk. Foods with folic acid include fruits and green leafy vegetables. Many grains, like bread and cereals, have vitamin B12 added to them.
If you don’t eat these foods, your doctor or nurse might recommend that you take a vitamin supplement. Vitamin supplements are pills, capsules, or liquids that have nutrients in them.
If you are a strict vegetarian or vegan and do not eat any meats, dairy foods, or eggs, you will not get enough vitamin B12 from your diet alone. To avoid getting vitamin B12 deficiency, you will need to take a vitamin B12 supplement or eat foods with vitamin B12 added to them.
What if I want to get pregnant?
— If you want to get pregnant, you should start taking a multivitamin at least 1 month before you start trying to get pregnant. Choose a “prenatal” multivitamin that has at least 400 micrograms of folic acid. Show your doctor the vitamin you plan to take to make sure the doses are right for you and your baby. Too much of some vitamins can be harmful.