Cookies on this website

We use cookies on our website. If you continue without changing your settings, we'll assume that you are happy to receive all cookies on the NHS Direct Wales website. However, if you would like to, you can change your cookie settings at any time.

Encyclopaedia


Anaemia, vitamin B12 and folate deficiency

Introduction

Anaemia, vitamin B12 and folate deficiency

Vitamin B12 or B9 (commonly called folate) deficiency anaemia occurs when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly.

Red blood cells carry oxygen around the body using a substance called haemoglobin.

Anaemia is the general term for having either fewer red blood cells than normal or having an abnormally low amount of haemoglobin in each red blood cell.

There are several different types of anaemia, and each one has a different cause. For example, a common form of anaemia is iron deficiency anaemia, which occurs when the body does not contain enough iron.

This topic focuses on anaemia caused by a lack of vitamin B12 or folate in the body.

Signs and symptoms

Vitamin B12 and folate perform several important functions in the body, including keeping the nervous system healthy.

A deficiency in either of these vitamins can cause a wide range of problems, including:

Some of these problems can also occur if you have a deficiency in vitamin B12 or folate, but do not have anaemia.

Read more about the symptoms of vitamin B12 deficiency or folate deficiency anaemia.

When to see your GP

You should see your GP if you think you may have a vitamin B12 or folate deficiency. These conditions can often be diagnosed based on your symptoms and the results of a blood test.

It's important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms will improve with treatment, some problems caused by the condition can be irreversible.

Read more about diagnosing vitamin B12 or folate deficiency anaemia.

What can cause a vitamin B12 or folate deficiency?

There are a number of problems that can lead to a vitamin B12 or folate deficiency, including:

  • pernicious anaemia – where your immune system attacks healthy cells in your stomach, preventing your body from absorbing vitamin B12 from the food you eat; this is the most common cause of vitamin B12 deficiency in the UK.
  • a lack of these vitamins in your diet – this is uncommon, but can occur if you have a vegan diet, follow a fad diet or have a generally poor diet for a long time
  • medication – certain medications, including anticonvulsants and proton pump inhibitors (PPIs), can affect how much of these vitamins your body absorbs

Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people aged 75 or over, and 1 in 20 people aged 65 to 74.

Read more about the causes of vitamin B12 or folate deficiency anaemia.

How vitamin B12 or folate deficiency anaemia is treated

Most cases of vitamin B12 and folate deficiency can be easily treated with injections or tablets to replace the vitamin you are deficient in.

Vitamin B12 supplements are usually given by injection at first. Then, depending on whether your B12 deficiency is related to your diet, you will either require B12 tablets between meals or regular injections. These treatments may be needed for the rest of your life.

Folic acid tablets are used to restore folate levels. These usually need to be taken for four months.

In some cases, improving your diet can help treat the condition and prevent it recurring. Vitamin B12 is found in meat, fish, eggs, dairy products, yeast extract (such as Marmite) and specially fortified foods. The best sources of folate include green vegetables such as broccoli, Brussels sprouts and peas.

Read more about treating vitamin B12 or folate deficiency.

Further problems

Although it is uncommon, vitamin B12 or folate deficiency (with or without anaemia) can lead to complications, particularly if you've been deficient in vitamin B12 or folate for some time.

Potential complications can include problems with the nervous system, temporary infertility, heart conditions, pregnancy complications and birth defects.

Some complications will improve with appropriate treatment, but others – such as problems with the nervous system – can be permanent.

Read more about the complications of vitamin B12 or folate deficiency anaemia.

^^ Back to top

Symptoms

Vitamin B12 or folate deficiency anaemia can cause a wide range of symptoms. These usually develop gradually at first, and can worsen if the condition goes untreated.

You should see your GP if you think you may have a vitamin B12 or folate deficiency. These conditions can often be diagnosed based on your symptoms and the results of a blood test. Read more about diagnosing vitamin B12 or folate deficiency anaemia.

It's important for vitamin B12 or folate deficiency anaemia to be diagnosed and treated as soon as possible because, although many of the symptoms will improve with treatment, some problems caused by the condition can be irreversible.

Anaemia symptoms

General symptoms of anaemia (where you have fewer red blood cells than normal or you have an abnormally low amount of a substance called haemoglobin in each red blood cell) include:

  • extreme tiredness (fatigue)
  • lack of energy (lethargy)
  • breathlessness
  • feeling faint
  • headaches
  • pale skin
  • noticeable heartbeats (palpitations)
  • hearing sounds coming from inside their body, rather than from an outside source (tinnitus)
  • loss of appetite and weight loss

Vitamin B12 deficiency

If you have anaemia caused by a vitamin B12 deficiency, you may have other symptoms in addition to those listed above, such as:

  • a pale yellow tinge to your skin
  • a sore and red tongue (glossitis)
  • mouth ulcers
  • pins and needles (paraesthesia)
  • changes in the way that you walk and move around
  • disturbed vision
  • irritability
  • depression
  • changes in the way you think, feel and behave
  • a decline in your mental abilities, such as memory, understanding and judgement (dementia)

Some of these symptoms can also occur in people who have a vitamin B12 deficiency, but have not developed anaemia.

Folate deficiency

Additional symptoms in people with anaemia caused by a folate deficiency can include:

  • numbness and tingling in the feet and hands
  • muscle weakness
  • depression
^^ Back to top

Causes

Vitamin B12 or folate deficiency anaemia occurs when a lack of either of these vitamins affects the body’s ability to produce fully functioning red blood cells.

Red blood cells carry oxygen around the body. Most people with vitamin B12 or folate deficiency anaemia have red blood cells that are underdeveloped and larger than normal. The medical term for this is "megaloblastic anaemia".

A vitamin B12 or folate deficiency can be the result of a variety of problems, some of which are described below.

Vitamin B12 deficiency:

Pernicious anaemia

Pernicious anaemia is the most common cause of vitamin B12 deficiency in the UK.

Pernicious anaemia is an autoimmune condition that affects your stomach. An autoimmune condition means your immune system (the body’s natural defence system that protects against illness and infection) attacks your body's healthy cells.

Vitamin B12 is absorbed into your body through your stomach. A protein called "intrinsic factor" attaches itself to vitamin B12, so it can be absorbed from the food you eat.

Pernicious anaemia causes your immune system to attack the cells in your stomach that produce the intrinsic factor, which means your body in unable to absorb vitamin B12.

The exact cause of pernicious anaemia is unknown, but the condition is more common in women around 60 years of age, people with a family history of the condition and those with another autoimmune condition, such as Addison’s disease or vitiligo.

Diet

Some people can develop a vitamin B12 deficiency as a result of not getting enough vitamin B12 from their diet.

A diet that includes meat, fish and dairy products usually provides enough vitamin B12, but people who don't regularly eat these foods – such as those following a vegan diet or who have a generally very poor diet – can become deficient.

Stores of vitamin B12 in the body can last around two to four years without being replenished, so it can take a long time for any problems to develop after a dietary change.

Conditions affecting the stomach

Some stomach conditions or stomach operations can prevent the absorption of enough vitamin B12. For example, a gastrectomy (a surgical procedure where part of your stomach is removed) increases your risk of developing a vitamin B12 deficiency.

Conditions affecting the intestines

Some conditions that affect your intestines can also stop you from absorbing the necessary amount of vitamin B12. For example, Crohn’s disease (a long-term condition that causes inflammation of the lining of the digestive system) can sometimes mean your body does not getting enough vitamin B12.

Medication

Some types of medicine can lead to a reduction in the amount of vitamin B12 in your body. For example, proton pump inhibitors (PPIs) – a medication sometimes used to treat indigestion – can make a vitamin B12 deficiency worse. PPIs inhibit the production of stomach acid, which is needed to release vitamin B12 from the food you eat.

Your GP will be aware of medicines that can affect your vitamin B12 levels, and will monitor you if they think it is necessary.

Functional vitamin B12 deficiency

Some people can experience problems related to a vitamin B12 deficiency, despite appearing to have normal levels of vitamin B12 in their blood.

This can occur due to a problem known as functional vitamin B12 deficiency – where there is a problem with the proteins that help transport vitamin B12 between cells. This results in neurological complications involving the spinal cord.

Folate deficiency:

Folate is a water-soluble vitamin (it dissolves in water), which means your body is unable to store it for long periods of time. Your body's store of folate is usually enough to last four months. This means you need folate in your daily diet to ensure your body has sufficient stores of the vitamin.

Like vitamin B12 deficiency anaemia, folate deficiency anaemia can develop for a number of reasons. Some are described below.

Diet

Good sources of folate include broccoli, Brussels sprouts, asparagus, peas, chickpeas and brown rice. If you don't regularly eat these types of foods, you may develop a folate deficiency.

Folate deficiency caused by a lack of dietary folate is more common in people who have a generally unbalanced and unhealthy diet, people who regularly misuse alcohol and people following a fad diet that doesn't involve eating good sources of folate.

Malabsorption

Sometimes your body may be unable to absorb folate as effectively as it should. This is usually due to an underlying condition affecting your digestive system, such as Coeliac disease.

Excessive urination

You may lose folate from your body if you urinate frequently. This can be caused by an underlying condition that affects one of your organs, such as:

  • congestive heart failure – where the heart is unable to pump enough blood around the body
  • acute liver damage – often caused by drinking excessive amounts of alcohol
  • long-term dialysis – where a machine that replicates the kidney function is used to filter waste products from the blood

Medication

Some types of medicine reduce the amount of folate in your body, or make the folate harder to absorb. These include some anticonvulsants (medication used to treat epilepsy), colestyramine, sulfasalazine and methotrexate.

Your GP will be aware of medicines that can affect your folate levels, and will monitor you if they feel it is necessary.

Other causes

Your body sometimes requires more folate than normal. This can cause folate deficiency if you cannot meet your body's demands for the vitamin. Your body may need more folate than usual if you:

  • are pregnant (see below)
  • have cancer
  • have a blood disorder – such as sickle cell anaemia (an inherited blood disorder which causes red blood cells to develop abnormally)
  • are fighting an infection or health condition that causes inflammation (redness and swelling)

Premature babies (born before the 37th week of pregnancy) are also more likely to develop a folate deficiency, because their developing bodies require higher amounts of folate than normal.

Pregnancy

If you are pregnant or trying to get pregnant, it is recommended that you take a 400 microgram folic acid tablet every day until you are 12 weeks pregnant. This will ensure that both you and your baby have enough folate, and will help your baby grow and develop.

Folic acid tablets are available with a prescription from your GP, or you can buy them over the counter from pharmacies, large supermarkets and health food stores.

If you are pregnant and have another condition that may increase your body's need for folate, such as those mentioned above, your GP will monitor you closely to prevent you from becoming anaemic.

In some cases, you may need a higher dose of folic acid. For example, if you have diabetes, you should take a 5 milligrams (5mg) supplement of folic acid instead of the standard 400 micrograms.

Read more about vitamins and nutrition in pregnancy.

^^ Back to top

Diagnosis

A diagnosis of vitamin B12 or folate deficiency anaemia can often be made by your GP based on your symptoms and the results of blood tests.

Blood tests

Different types of blood tests can be carried out to check:

  • whether you have a lower level of haemoglobin (a substance that transports oxygen) than normal
  • whether your red blood cells are larger than normal
  • the level of vitamin B12 in your blood
  • the level of folate in your blood

These tests can often help identify people with a possible vitamin B12 or folate deficiency, but they are not necessarily conclusive, because some people can have problems with normal levels of these vitamins, and others can have low levels despite having no symptoms.

This means it is very difficult to devise definitive criteria for the diagnosis of vitamin B12 or folate deficiency, and this is why it is important for your symptoms to be taken into account when a diagnosis is made.

A particular drawback of testing vitamin B12 levels is that the current widely-used blood test only measures the total amount of vitamin B12 in your blood.

This means it measures forms of vitamin B12 that are "active" and can be used by your body, as well as the "inactive" forms, which can't. If a significant amount of the vitamin B12 in your blood is "inactive", a blood test may show that you have normal B12 levels, even though your body cannot use much of it.

There are some types of blood test that may help determine if the vitamin B12 in your blood can be used by your body, but these are not yet widely available.

Identifying the cause

If your symptoms and test results indicate you are likely to be deficient in either vitamin B12 or folate, your GP may arrange further tests to help identify the cause. This will help determine the most appropriate treatment for you.

For example, you may have additional blood tests to check for a condition called pernicious anaemia. This is an autoimmune condition (where your immune system produces antibodies to attack healthy cells), which means you are unable to absorb vitamin B12 from the food you eat.

Like the blood tests used in diagnosing vitamin B12 or folate deficiencies, tests for pernicious anaemia are not always conclusive, but they can often give your GP a good idea of whether you have the condition.

Referral to a specialist

In some circumstances, you may be referred to one of the following specialists.

Haematologist

A haematologist is a doctor who specialises in treating blood conditions. You will probably be referred to a haematologist if you have vitamin B12 or folate deficiency anaemia and:

  • your GP is uncertain what is causing the condition
  • you are pregnant
  • your symptoms suggest your nervous system (the brain, nerves and spinal cord) has been affected – this can cause problems such as changes in your vision, and numbness and tingling in your hands and feet

Gastroenterologist

A gastroenterologist is a doctor who specialises in conditions that affect the digestive system. You may be referred to a gastroenterologist if your GP suspects you do not have enough vitamin B12 or folate because your digestive system is not absorbing it properly.

For example, your GP may refer you to a gastroenterologist if they suspect you may have coeliac disease or Crohn's disease.

Dietitian

A dietitian is a healthcare professional who specialises in nutrition. They can give you advice about your diet.

You may be referred to a dietitian if your GP suspects you have a vitamin B12 or folate deficiency caused by a poor diet. The dietitian can devise a personalised eating plan for you to increase the amount of vitamin B12 or folate in your diet.

Read our page on B vitamins and folic acid for information about good sources of these vitamins

^^ Back to top

Treatment

The treatment for vitamin B12 or folate deficiency anaemia depends on what is causing the condition.

Most cases can be easily treated with injections or tablets to replace the vitamin you are deficient in.

Vitamin B12 deficiency anaemia

Vitamin B12 deficiency anaemia is usually treated with injections of vitamin B12, in a form called hydroxocobalamin.

At first, you will have these injections every other day for two weeks, or until your symptoms have stopped improving. Your GP or nurse will give the injections.

After this initial period, your treatment will depend on whether the cause of your vitamin B12 deficiency is related to your diet. The most common cause of vitamin B12 deficiency in the UK is pernicious anaemia, which is not related to your diet.

Read more about the causes of vitamin B12 or folate deficiency.

Diet-related

If your vitamin B12 deficiency is caused by a lack of the vitamin in your diet, you may be prescribed vitamin B12 tablets to take every day between meals. Alternatively, you may need to have an injection of hydroxocobalamin twice a year.

People who find it difficult to get enough vitamin B12 in their diets, such as those following a vegan diet, may need vitamin B12 tablets for life.

Although it is less common, people with vitamin B12 deficiency caused by a prolonged poor diet may be advised to stop taking the tablets once their vitamin B12 levels have returned to normal and their diet has improved.

Good sources of vitamin B12 include:

  • meat
  • salmon and cod
  • milk and other dairy products
  • eggs

If you are a vegetarian or vegan, or are looking for alternatives to meat and dairy products, there are other foods that contain vitamin B12, such as yeast extract (including Marmite), as well as some fortified breakfast cereals and soy products.

Check the nutrition labels while food shopping to see how much vitamin B12 different foods contain.

Not diet-related

If your vitamin B12 deficiency is not caused by a lack of vitamin B12 in your diet, you will usually need to have an injection of hydroxocobalamin every three months for the rest of your life.

If you have had neurological symptoms (symptoms that affect your nervous system, such as numbness or tingling in your hands and feet) caused by a vitamin B12 deficiency, you will be referred to a haematologist, and you may need to have injections every two months. Your haematologist will advise on how long you need to keep taking the injections.

For injections of vitamin B12 given in the UK, hydroxocobalamin is preferred to an alternative called cyanocobalamin. This is because hydroxocobalamin stays in the body for longer.

If you need regular injections of vitamin B12, cyanocobalamin would need to be given once a month, whereas hydroxocobalamin can be given every three months.

Cyanocobalamin injections are therefore not recommended and not routinely available on the NHS. However, if you need replacement tablets of vitamin B12, these will be cyanocobalamin.

Folate deficiency anaemia

To treat folate deficiency anaemia, your GP will usually prescribe daily folic acid tablets to build up your folate levels. They may also give you dietary advice so you can increase your folate intake.

Good sources of folate include:

  • broccoli
  • Brussels sprouts
  • asparagus
  • peas
  • chickpeas
  • brown rice

Most people will need to take folic acid tablets for about four months. However, if the underlying cause of your folate deficiency anaemia continues, you may have to take folic acid tablets for longer – possibly for life.

Before you start taking folic acid, your GP will check your vitamin B12 levels to make sure they are normal. This is because folic acid treatment can sometimes improve your symptoms so much that it masks an underlying vitamin B12 deficiency. If a vitamin B12 deficiency is not detected and treated, it could affect your nervous system.

Monitoring your condition

To ensure your treatment is working, you may need to have further blood tests.

If you have been taking folic acid tablets, you may be tested again once the treatment has finished.

Most people who have had a vitamin B12 or folate deficiency will not need further monitoring unless their symptoms return, or their treatment is ineffective. If your GP feels it is necessary, you may have to return for an annual blood test to see whether your condition has returned.

^^ Back to top

Complications

As most cases of vitamin B12 deficiency or folate deficiency can be easily and effectively treated, complications are rare.

However, complications can occasionally develop, particularly if you have been deficient in either vitamin for some time.

Anaemia complications

All types of anaemia, regardless of what it is caused by, can lead to heart and lung complications as the heart struggles to pump oxygen to the vital organs.

Adults with severe anaemia are at risk of developing:

  • an abnormally fast heart beat (tachycardia)
  • heart failure – where the heart fails to pump enough blood around the body at the right pressure

Vitamin B12 deficiency

A lack of vitamin B12 (with or without anaemia) can cause the following complications:

Neurological changes

A lack of vitamin B12 can cause neurological problems (issues affecting your nervous system), such as:

If neurological problems do develop, they may be irreversible.

Infertility

Vitamin B12 deficiency can sometimes lead to temporary infertility (an inability to conceive). This usually improves with appropriate vitamin B12 treatment.

Stomach cancer

If you have a vitamin B12 deficiency caused by pernicious anaemia (a condition where your immune system attacks healthy cells in your stomach), your risk of developing stomach cancer is increased.

Neural tube defects

If you are pregnant, not having enough vitamin B12 can increase the risk of your baby developing a serious birth defect known as a neural tube defect. The neural tube is a narrow channel that eventually forms the brain and spinal cord.

Examples of neural tube defects include:

  • spina bifida – where the baby's spine doesn't develop properly
  • anencephaly – where a baby is born without parts of the brain and skull
  • encephalocele – where a membrane or skin-covered sac containing part of the brain pushes out of a hole in the skull

Folate deficiency

A lack of folate (with or without anaemia) can also cause complications, some of which are outlined below.

Infertility

As with a lack of vitamin B12, a folate deficiency can also affect your fertility. However, this is only temporary and can usually be reversed with folate supplements.

Cardiovascular disease

Research has shown a lack of folate in your body may increase your risk of cardiovascular disease (CVD).

CVD is a general term that describes a disease of the heart or blood vessels, such as coronary heart disease (CHD).

Cancer

Research has shown that folate deficiency can increase your risk of some cancers, such as colon cancer.

Problems in childbirth

A lack of folate during pregnancy may increase the risk of the baby being born prematurely (before the 37th week of pregnancy) or having a low birthweight.

The risk of placental abruption may also be increased. This is a serious condition where the placenta starts to come away from the inside of the womb wall, causing tummy (abdominal) pain and bleeding from the vagina.

Neural tube defects

As with a vitamin B12 deficiency, a lack of folate can also affect an unborn baby's growth and development in the womb (uterus). This increases the risk of neural tube defects such as spina bifida developing in the unborn baby.

^^ Back to top


The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 09/09/2014 11:22:35

Please leave your rating


Thank you for your rating
Average Rating
based on 24 ratings


3 ratings
1 rating
0 rating
6 ratings
14 ratings
Please leave your rating

Average Rating
based on 24 ratings
3 ratings
1 rating
0 rating
6 ratings
14 ratings
| Share
1000 Lives Campaign health challenge wales Twf change for life