Encyclopaedia


Anaemia, vitamin B12 and folate deficiency

Introduction

Vitamin B12 deficiency anaemia or folate deficiency anaemia occur when a lack of vitamin B12 or folate causes the body to produce abnormally large red blood cells that cannot function properly.

The main symptoms of vitamin B12 deficiency or folate deficiency anaemia are:

  • tiredness
  • lethargy (lack of energy)

Anaemia

There are several different types of anaemia, and each one has a different cause. This article focuses on anaemia that is caused by a lack of vitamin B12 or folate in the body.

This article also covers pernicious anaemia (an autoimmune condition where the body’s immune system attacks cells in the stomach), which is the most common cause of vitamin B12 deficiency.

The most common type of anaemia is iron deficiency anaemia, which occurs when the body does not contain enough iron to produce red blood cells.

See the Health A-Z topic about Iron deficiency anaemia for more information about this condition

Vitamin B12 and folate

Vitamin B12 and folate work together to help the body produce red blood cells. They also have several other important functions:

  • vitamin B12 helps to keep the nervous system (brain, nerves and spinal cord) healthy
  • folate is important for pregnant women because it reduces the risk of birth defects in unborn babies

Vitamin B12 is found in:

  • meat
  • eggs
  • dairy products

The best source of folate is green vegetables such as:

  • broccoli
  • Brussel sprouts
  • peas

How common is vitamin B12 deficiency or folate deficiency?

Both vitamin B12 deficiency and folate deficiency are more common in older people, affecting around 1 in 10 people above the age of 75. Vitamin B12 deficiency is rare in younger people, although those who follow a strict vegan diet (a diet that only contains food from plants) may be more at risk.

Pernicious anaemia, which is the most common cause of vitamin B12 deficiency, affects 1 in 10,000 people in northern Europe.

Outlook

Vitamin B12 deficiency anaemia can be treated with vitamin B12 supplements. Vitamin B12 is usually given by injection every other day for two weeks, followed by tablets, until the deficiency is under control.

Folate deficiency anaemia can be treated with folate supplements. Folic acid tablets are used to restore folate levels, which usually need to be taken for four months.

Depending on the underlying cause of a vitamin B12 or folate deficiency, dietary improvements can prevent the condition returning, or supplements may need to be taken for life. 

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Symptoms

The symptoms of each type of anaemia vary depending on the underlying cause of the condition.  However, there are some more general symptoms, which are associated with all types of anaemia. These include:

  • fatigue, (extreme tiredness)
  • lethargy (lack of energy)
  • breathlessness (dyspnoea)
  • faintness,
  • irregular heart beats (palpitations),
  • headache,
  • tinnitus (the perception of a noise in one or both ears, or inside your head, which comes from inside your body; for example, a ringing in your ears)
  • loss of appetite.

Vitamin B12 deficiency

If your anaemia is being caused by a vitamin B12 deficiency, you may have the symptoms listed above, as well as:

  • a yellow tinge to your skin (jaundice)
  • a sore and red tongue (glossitis)
  • ulcers inside your mouth,
  • an altered, or reduced, sense of touch,
  • a reduced ability to feel pain,
  • a change in the way you walk and move around,
  • disturbed vision,
  • irritability,
  • depression – feelings of extreme sadness that last for a long time
  • psychosis – a condition that affects your mind and changes the way you think, feel and behave
  • dementia – a decline in your mental abilities, such as your memory, understanding and judgement

Folate deficiency

As well as the general symptoms of anaemia, a folate deficiency may also cause:

  • loss of sensation, such as a reduced sense of touch or pain
  • muscle weakness
  • depression.
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Causes

Vitamin B12 deficiency and folate deficiency can be caused by a number of different factors. These factors can cause anaemia because they affect the body’s ability to produce fully functioning red blood cells (cells that carry oxygen around the body).

Some possible causes of vitamin B12 deficiency and folate deficiency are described below.

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 (part of your digestive system that helps to digest food by mixing it with acids). An autoimmune condition is when the immune system (the body’s natural defence system that protects against illness and infection) starts to attack your body's healthy cells.

Vitamin B12 is absorbed into your body through your stomach. The vitamin combines with a protein substance called intrinsic factor, which is produced in the stomach, so that it can be absorbed from the food that you eat.

Pernicious anaemia causes your immune system to attack the cells in your stomach that produce the intrinsic factor. This means that your body does not produce enough intrinsic factor and cannot absorb vitamin B12. This causes a deficiency in vitamin B12.

It is not known what triggers the immune system to attack the cells in this way, but there are some risk factors.

Risk factors

Pernicious anaemia may be more likely if:

  • you are around 60 years of age – pernicious anaemia is most common at this age
  • you are female – pernicious anaemia affects slightly more women than men
  • you have a family history of the condition – nearly a third of people with pernicious anaemia also have a family member with the condition
  • you have another autoimmune condition, such as Addison’s disease (a disorder that affects the adrenal glands) or vitiligo (a condition that causes pale patches of skin to develop) – there is an association between pernicious anaemia and other autoimmune conditions

Vitamin B12 deficiency

Vitamin B12 deficiency can also be caused by a number of other factors, although these are rare. Some possible causes are described below.

Diet

The body usually stores enough vitamin B12 to last for approximately two to four years. However, it is important to have vitamin B12 in your diet to ensure that the store is kept at a healthy level.

Most people will eat enough vitamin B12 by having a diet that includes meat, fish or dairy products. People who may not have enough vitamin B12 in their diet include vegans (people whose diet only contains food from plants) or those who have a very poor diet for a prolonged period of time.

Conditions affecting the stomach

Some stomach conditions, or procedures that are carried out on the stomach, can prevent it absorbing enough vitamin B12. For example, a gastrectomy (a surgical procedure where part of your stomach is removed) increases your risk of developing vitamin B12 deficiency anaemia.

See the A-Z topic about Gastrectomies for more information about this procedure.

Conditions affecting the intestines

Some conditions that affect your intestines (part of the digestive system) stop you from absorbing as much vitamin B12 as normal. For example, Crohn's disease (a long-term condition that causes inflammation of the lining of the digestive system) can sometimes result in your body not having enough vitamin B12.

See the Health A-Z topic about Crohn’s disease for more information about this condition.

Medication

Some types of medicine can reduce the amount of vitamin B12 in your body. For example, proton pump inhibitors (PPIs) (a medication that treats 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 any medicines that can affect your vitamin B12 levels, and will monitor you if they think it is necessary.

Folate deficiency anaemia

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

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

Diet

Some people do not have enough folate in their daily diet. This may be because:

  • they have recently changed their diet – for example, to lose weight
  • their diet is not healthy and balanced

Malabsorption

Sometimes your body may be unable to absorb folate as effectively as it should. This is usually the result of an underlying condition affecting your digestive system, such as irritable bowel syndrome (IBS) (a long-term disorder that causes abdominal pain, diarrhoea and constipation).

See Health A-Z topic about IBS for more information about this condition. 

Excessive urination

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

  • kidneys (two bean-shaped organs that filter the blood) 
  • liver (the largest organ in the body, performing many vital functions)

The following can all make you urinate frequently:

  • congestive heart failure – where the heart is unable to pump enough blood around the body
  • acute liver damage – which often occurs as a result of drinking excessive amounts of alcohol
  • long-term dialysis – where a dialysis machine filters waste products from the blood

Medication

Some types of medicine can reduce the amount of folate in your body, or make the folate harder to absorb. Your GP will be aware of any medicines that can affect your folate levels and will monitor you if they feel that it is necessary.

Other causes

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

  • are pregnant
  • have cancer
  • have a blood disorder, such as sickle cell anaemia (an inherited disorder that causes your blood cells to change shape)
  • are fighting an infection or health condition that causes inflammation (redness and swelling)

Premature babies (babies born before week 37 of the pregnancy) are also more prone to developing folate deficiency anaemia because their developing bodies cannot meet the demand for the folate vitamin.

Pregnancy

If you are pregnant or planning to get pregnant, take a daily supplement of 0.4mg of folic acid until you are 12 weeks pregnant. This will ensure that both you and your baby have enough folate, and it will help your baby to 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
  • health food stores

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

In some cases, you may need to take a higher dose of folic acid. For example, if you have diabetes (a long-term condition that is caused by too much glucose in the blood) you should take a 5mg supplement of folic acid instead of the standard 0.4mg.

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Diagnosis

To diagnose a vitamin B12, or folate deficiency, your GP will ask you to describe your symptoms and will look carefully at your medical history. They may also carry out a physical examination

Blood tests

If your GP suspects you have vitamin B12 or folate deficiency anaemia, they will usually require you to have a blood test in order to confirm the diagnosis. A sample of your blood will be taken and sent to a laboratory where a 'full blood count' test will be carried out.

If you have less haemoglobin than normal, you will be diagnosed with anaemia. Your blood can also be tested to see how much vitamin B12 and folate you have. If your tests show that you are deficient in either of these vitamins, it will help your GP to determine which type of anaemia you have.

Once your GP has determined that you have vitamin B12, or folate deficiency, anaemia, they may have to carry out further tests to help establish the underlying cause of your deficiency.

For example, vitamin B12 deficiency is most commonly caused when the antibodies in your immune system (which usually protect against and fight infection) start to attack cells in your stomach, which help your body to absorb the vitamin (see 'causes' section). Your blood can be tested to see if it contains the antibodies which attack the stomach cells.

Once your GP has determined the underlying cause of your anaemia, they will be able to provide you with the most appropriate treatment.

Referral

In some circumstances, you may have to be referred for further testing, or treatment, with a specialist. Some of the specialists you may be referred to are outlined below.

Haematologist

A haematologist is a doctor who specialises in blood conditions. If you are pregnant and have been diagnosed with vitamin B12 or folate deficiency anaemia, you will be referred to a haematologist. This is because a vitamin B12 or folate deficiency can sometimes affect your developing baby (see 'complications' section for further information).

You will also be referred to a haematologist if you are displaying symptoms which suggest that your nervous system has been affected by vitamin B12 or folate deficiency anaemia. These symptoms may include a reduced, or altered, sense of touch and pain, a change in your vision, or an inability to control your muscles.

If the cause of your vitamin B12 or folate deficiency is unknown, or if a more serious underlying cause is suspected, you may also be referred to a haematologist so that the cause of your deficiency can be investigated further.

Gastroenterologist

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

Dietician

A dietician is a health professional who specialises in nutrition. A dietician can give you advice about your diet, and inform you about ways that you can adapt and change it in order to help treat your condition.

If your vitamin B12 or folate deficiency is thought to be caused by a poor diet, you will be referred to a dietician, who will be able to devise a personalised eating plan to help increase the amount of vitamin B12 and folate that you eat.

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Treatment

The treatment for your anaemia will depend on whether it is being caused by a lack of vitamin B12 or folate. The different treatments are outlined below.

Vitamin B12 deficiency anaemia

Vitamin B12 deficiency anaemia is usually treated using injections of vitamin B12. The vitamin is in the form of a substance known as hydroxocobalamin. At first, you will have injections every other day for two weeks. These injections will be given to you by your GP or nurse. After this, your dosage will depend on the cause of your vitamin B12 deficiency.

  • If your vitamin B12 deficiency is not caused by a lack of the vitamin in your diet, you will usually need to have an injection of hydroxocobalamin every three months for the rest of your life. Some people who have had neurological symptoms because of vitamin B12 deficiency will need injections every two months.
  • If your vitamin B12 deficiency is caused by a lack of the vitamin in your diet, you will be prescribed vitamin B12 tablets. People who may struggle to get enough vitamin B12 in their diets, such as vegans, may need to take vitamin B12 tablets for life. However, if this does not apply to you, your GP will be able to stop your tablets once your vitamin B12 levels return to normal.

Folate deficiency anaemia

To treat folate deficiency anaemia, your GP will normally prescribe folic acid tablets to help build up your folate levels. Most people will need to take these tablets for approximately four months.

However, if the underlying cause of your folate deficiency anaemia is persistent, you may have to take folic acid tablets for a longer period, and maybe for life.

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

Self-help

If you have been diagnosed with vitamin B12 or folate deficiency anaemia, there are some ways that you can treat the condition yourself. It is important to incorporate lots of vitamin B12 and folate in your everyday diet.

Increasing your vitamin B12 intake

Good sources of vitamin B12 are meat, eggs and dairy products. If you incorporate foods like this into a healthy, balanced diet, you should be able to increase your vitamin B12 intake.

If you are a vegetarian, or vegan, or you are looking for alternative to meat and dairy products, there are some other foods which contain vitamin B12. Some fortified breakfast cereals and some soy products contain vitamin B12. You can check the nutrition labels on these foods to see how much vitamin B12 they contain.

Increasing your folate intake

The best way to increase your intake of folate is to eat more green vegetables. Vegetables, such as broccoli, Brussels sprouts, asparagus, peas, chickpeas and brown rice all contain naturally high levels of folate.

Monitoring your condition

To ensure that your treatment is working, your vitamin B12 and folate levels will have to be monitored. Shortly after starting treatment, you will need to have a blood test to check that your treatment is starting to help restore your vitamin B12 and folate levels. You will then need another blood test after approximately eight weeks to confirm that your treatment has been successful.

Most people who have had a B12 or folate deficiency will not require further monitoring unless their symptoms return, or if their treatment is not proving to be effective. If your GP feels it necessary, you may have to return for an annual blood test, to check that your condition has not recurred.

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Complications

As most cases of vitamin B12 or folate deficiency can be easily and effectively treated, complications are relatively rare. However, in some cases, a deficiency in these vitamins can result in complications, particularly if you have been deficient in vitamin B12 or folate for some time.

In severe cases, any type of anaemia can cause you to develop complications which affect your heart and lungs, stopping them from working as well as they should. If your anaemia is severe, you may have to be admitted to hospital so that your heart and lungs can be carefully monitored. A lack of vitamin B12 or folate can also cause other complications, some of which are outlined below.

Complications of vitamin B12 deficiency

Nervous system

A lack of vitamin B12 can affect your nervous system (see 'symptoms' section). For example, you may experience problems with your vision, or have memory loss.

Fertility

Vitamin B12 deficiency can sometimes affect your fertility, and cause temporary sterility (an inabilty to conceive). However, you will not be sterile permanently, and the condition can be reversed using vitamin supplements.

Neural tube defects

If you are pregnant, not having enough vitamin B12 can increase the risk of you baby developing a neural tube defect. Neural tube defects affect your baby's growth and development. Spina bifida (where the baby's spine does not form properly) and anencephaly (where the baby's brain and skull bones do not form properly) are both examples of neural tube defects.

Complications of folate deficiency

Fertility

As with a lack of vitamin B12, a deficiency of folate can also affect your fertility. However, the effects are only temporary, and can be reversed by using vitamin supplements.

Cardiovascular disease

Research has shown that a lack of folate in your body may increase your risk of developing cardiovascular disease. Cardiovascular disease is when your heart and the rest of your circulation system fail to work as well as they should.

Cancer

Research has shown that folate deficiency can be linked to some cancers. Although a lack of folate is never be the sole cause of a cancer developing, it may be a contributing factor.

Neural tube defects

As with a vitamin B12 deficiency, a lack of folate can also affect your baby's growth and development in the womb, making them more prone to developing neural tube defects, such as spina bifida.

Premature birth

As well as affecting your baby's growth, a lack of folate during your pregnancy may also increase the risk of your baby being born prematurely.

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Selected links

 

  • Vitamin B12 (Food Standards Agency)
  • Eat well, be well - pregnancy  (Food Standards Agency )
  • Anaemia due to vitamin B12 deficiency (Net Doctor )
  • Pernicious anaemia (BBC Health)
  • Folic acid (Food Standards Agency)
  • Vitamin B12 deficiency and pernicious anaemia (Patient UK)
  • Vitamin B12 and folate test (Lab Test UK)

     

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    The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.

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