Vitamin B12 or folate deficiency anaemia

Vitamin B12 or B9 (most people call B9 folate) deficiency anaemia happens when your body doesn't get enough of either vitamin. Without them, the body makes red blood cells that are abnormally large, and these cells can't do their job properly.

Red blood cells carry oxygen around the body, and they do this using a substance called haemoglobin.

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

There are several types of anaemia, and each has its own cause. Iron deficiency anaemia is one example, and it occurs when the body doesn't have enough iron.

Vitamin B12 and folate do several important jobs in your body, and one of them is keeping your nervous system healthy. If you are short of either vitamin, you can have many different problems, such as:

• extreme tiredness
• a lack of energy
• pins and needles (paraesthesia)
• a sore and red tongue
• mouth ulcers
• muscle weakness
• disturbed vision
• psychological problems, which may include depression and confusion
• problems with memory, understanding and judgement

Some of these problems can also happen if you have a vitamin B12 or folate deficiency but don't have anaemia.

See a doctor if you think you may have a vitamin B12 or folate deficiency. Doctors can often diagnose these conditions from your symptoms and the results of a blood test.

Vitamin B12 or folate deficiency anaemia should be diagnosed and treated as soon as possible. Many of the symptoms get better with treatment, but some problems caused by the condition can be irreversible.

A number of problems can lead to a vitamin B12 or folate deficiency, including:

• pernicious anaemia, where your immune system attacks healthy cells in your stomach and stops your body 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, which is uncommon but can happen if you eat a vegan diet, follow a fad diet or have a generally poor diet for a long time
• medicine, because certain medicines, 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. They affect around 1 in 10 people aged 75 or over, and 1 in 20 people aged 65 to 74.

Most cases of vitamin B12 and folate deficiency anaemia are easy to treat. You are given injections or tablets that replace the vitamins your body is missing.

Vitamin B12 is usually given by injection at first. After that, the treatment depends on whether your B12 deficiency is linked to your diet. If it is, you'll need B12 tablets between meals. If it isn't, you'll need regular injections. You may need these treatments for the rest of your life.

Folic acid tablets are used to bring folate levels back up. You usually have to take them for four months.

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

Vitamin B12 or folate deficiency anaemia doesn't often lead to complications, but it can happen, especially if you've been short of vitamin B12 or folate for some time. This applies whether or not you have anaemia as well.

The complications can include:

• problems with the nervous system
• temporary infertility
• heart conditions
• pregnancy complications and birth defects

Adults with severe anaemia are also at risk of developing heart failure.

Some of these problems get better with the right treatment. Others can be permanent, and problems with the nervous system are one example.

Vitamin B12 or folate deficiency anaemia can cause many different symptoms. They usually come on slowly, but they can get worse if the condition isn't treated.

Anaemia means you have fewer red blood cells than normal, or you have an unusually low amount of a substance called haemoglobin in each red blood cell. The general symptoms of anaemia may include:

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

If your anaemia is caused by a vitamin B12 deficiency, you may have other symptoms as well as those listed above. These include:

• 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 happen in people who have a vitamin B12 deficiency but have not developed anaemia.

People with anaemia caused by folate deficiency can have some other symptoms as well. These can include:

• symptoms related to anaemia
• reduced sense of taste
• diarrhoea
• numbness and tingling in the feet and hands
• muscle weakness
• depression

See a doctor if you have symptoms of vitamin B12 or folate deficiency anaemia. Doctors can often diagnose these conditions from your symptoms and the result of a blood test.

Vitamin B12 or folate deficiency anaemia needs to be diagnosed and treated as soon as possible. Many of the symptoms get better with treatment, but some problems caused by the condition can be irreversible if it's left untreated. The longer it goes untreated, the higher the chance of permanent damage.

Vitamin B12 or folate deficiency anaemia happens when you don't have enough of either vitamin, and your body can't make fully working red blood cells as a result.

Red blood cells carry oxygen around the body. In most people with this type of anaemia, the red blood cells are underdeveloped and larger than normal. Doctors call this "megaloblastic anaemia".

A lack of vitamin B12 or folate can come from several different problems, and some of them are described below.

Pernicious anaemia is the most common cause of vitamin B12 deficiency in the UK. It's an autoimmune condition that affects your stomach. That means your immune system (the body's natural defence system that protects against illness and infection) attacks your own healthy cells.

In your stomach, vitamin B12 combines with a protein called intrinsic factor. The body then absorbs this mix of vitamin B12 and intrinsic factor in a part of the gut called the distal ileum.

With pernicious anaemia, your immune system attacks the cells in your stomach that make intrinsic factor. Your body can then no longer absorb vitamin B12.

Nobody knows the exact cause of pernicious anaemia. But it's more common in women around 60 years of age, in people with a family history of the condition, and in those who have another autoimmune condition, such as Addison's disease or vitiligo.

Some people develop a vitamin B12 deficiency because they don't get enough vitamin B12 from what they eat.

A diet that includes meat, fish and dairy products usually gives you enough vitamin B12. But if you don't eat these foods regularly, you can become deficient. This can happen to people following a vegan diet, and to those whose diet is generally very poor.

The body keeps stores of vitamin B12 that can last around two to four years without being replenished. So after a change in diet, it can take a long time before any problems show up.

Some stomach conditions and some stomach operations can stop your body from absorbing enough vitamin B12. A gastrectomy is one example. This is an operation where part of your stomach is removed, and it raises your risk of developing a vitamin B12 deficiency.

Some conditions that affect your intestines can stop your body from absorbing enough vitamin B12. Crohn's disease is one example. It's a long-term condition that causes inflammation of the lining of the digestive system, and it can sometimes mean your body doesn't get enough vitamin B12.

Some medicines can lower the amount of vitamin B12 in your body. Proton pump inhibitors (PPIs) are one example. Doctors sometimes use them to treat indigestion, and they can make a vitamin B12 deficiency worse. They cut down the stomach acid your body makes, and you need that acid to release vitamin B12 from the food you eat.

Your doctor will know which medicines can affect your vitamin B12 levels and will keep a check on you if it's needed.

Some people have problems linked to vitamin B12 deficiency even though their blood tests seem to show normal levels of vitamin B12. This can happen with functional vitamin B12 deficiency, where something goes wrong with the proteins that carry vitamin B12 between cells. The result is neurological complications that affect the spinal cord.

Folate dissolves in water, so your body can't store it for long. Its store of folate usually lasts about four months, which is why you need folate in your daily diet to keep your stores topped up.

Folate deficiency anaemia, like vitamin B12 deficiency anaemia, can develop for a number of reasons. Some of them are described below.

Broccoli, Brussels sprouts, asparagus, peas, chickpeas and brown rice are all good sources of folate. If you don't eat these kinds of foods regularly, you may develop a folate deficiency.

Folate deficiency from a lack of folate in the diet is more common in people whose diet is generally unbalanced and unhealthy. It is also more common in people who regularly misuse alcohol, and in people following a fad diet that leaves out good sources of folate.

Sometimes your body can't take in folate as well as it should, and this can lead to folate deficiency anaemia. Usually the cause is another condition affecting your digestive system, such as coeliac disease.

If you pass urine very often, your body can lose folate. Frequent urination can come from an underlying condition that affects one of your organs, such as:

• congestive heart failure, where the heart can't pump enough blood around the body
• acute liver damage, often caused by drinking excessive amounts of alcohol
• long-term dialysis, where a machine that does the work of the kidneys is used to filter waste products from the blood

Some medicines lower the amount of folate in your body, or make it harder for your body to absorb it. This can lead to folate deficiency anaemia. The medicines include some anticonvulsants (medicines used to treat epilepsy), colestyramine, sulfasalazine and methotrexate.

Your doctor will know which medicines can affect your folate levels, and will monitor you if necessary.

Sometimes your body needs more folate than it normally does. If you can't meet that extra demand, you can develop folate deficiency.

You 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 a health condition that causes inflammation (redness and swelling)

Premature babies (born before the 37th week of pregnancy) are also more likely to develop folate deficiency. Their developing bodies need higher amounts of folate than normal.

If you're pregnant or trying to get pregnant, you should take a 400 microgram folic acid tablet every day until you're 12 weeks pregnant. This makes sure both you and your baby have enough folate, and it helps your baby grow and develop.

You can get folic acid tablets with a prescription from your doctor. You can also buy them over the counter from pharmacies, large supermarkets and health food stores.

Some conditions raise your body's need for folate, such as those mentioned above. If you're pregnant and have one of them, your doctor will monitor you closely to stop you becoming anaemic.

In some cases you may need a higher dose of folic acid. If you have diabetes, for example, you should take a 5 milligrams (5mg or 5,000 micrograms) supplement of folic acid instead of the standard 0.4 milligrams (0.4mg or 400 micrograms).

Your doctor can often diagnose vitamin B12 or folate deficiency anaemia from your symptoms and the results of blood tests.

Doctors can use several blood tests to help find people who may have a vitamin B12 or folate deficiency. These tests 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

The results aren't always clear-cut, though. Some people have problems with their normal levels of these vitamins, and others have low levels without any symptoms at all. So your symptoms need to be taken into account when a diagnosis is made.

One particular drawback with vitamin B12 testing is that the blood test most widely used at present only measures the total amount of vitamin B12 in your blood.

That means it picks up the "active" forms of vitamin B12, which your body can use, and also the "inactive" forms, which it can't. If a significant amount of the vitamin B12 in your blood is "inactive", the test may show normal B12 levels even though your body can't use much of it.

Some other blood tests may help show whether the vitamin B12 in your blood can be used by your body, but these aren't yet widely available.

If your symptoms and blood test results point to a vitamin B12 or folate deficiency, your doctor may arrange more tests. Finding the cause matters, because it helps decide which treatment suits you best.

You may, for example, have extra blood tests to check for a condition called pernicious anaemia. This is an autoimmune condition, which means your immune system makes antibodies that attack healthy cells. As a result, your body can't absorb vitamin B12 from the food you eat.

The tests for pernicious anaemia aren't always conclusive, but they often give your doctor a good idea of whether you have it.

Your doctor may refer you to a specialist for more tests or for treatment. Which specialist depends on the likely reason for your vitamin B12 or folate deficiency anaemia:

• a haematologist (a specialist in blood conditions), if your doctor is unsure of the cause, if you're pregnant, or if your symptoms suggest your nervous system has been affected
• a gastroenterologist (a specialist in conditions of the digestive system), if your doctor suspects you don't have enough vitamin B12 or folate because your digestive system isn't absorbing it properly
• a dietitian (a specialist in nutrition), if your doctor suspects your vitamin B12 or folate deficiency is caused by a poor diet

A dietitian can draw up an eating plan for you, to increase the amount of vitamin B12 or folate in your diet.

What treatment you need for vitamin B12 or folate deficiency anaemia depends on what is causing it. For most people it's simple to treat, with injections or tablets that replace the vitamins your body is missing.

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

At first, you'll have these injections every other day for two weeks, or until your symptoms have stopped improving. A doctor or nurse will give them to you.

After this first period, your treatment depends on whether your vitamin B12 deficiency is related to your diet. The most common cause of vitamin B12 deficiency in the UK is pernicious anaemia, and that isn't related to your diet.

If your vitamin B12 deficiency comes from a lack of the vitamin in your diet, your doctor may prescribe vitamin B12 tablets. You take them every day, between meals. Or you may need an injection of hydroxocobalamin twice a year instead.

Some people find it hard to get enough vitamin B12 from food, for example those following a vegan diet. They may need vitamin B12 tablets for life.

It's less common, but if your deficiency was caused by a prolonged poor diet, you may be advised to stop the tablets once your vitamin B12 levels are back to normal and your diet has improved.

Good sources of vitamin B12 include:

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

If you're a vegetarian or vegan, or you're looking for alternatives to meat and dairy products, some other foods also contain vitamin B12. These include yeast extract (Marmite is one), some fortified breakfast cereals and soy products.

When you shop for food, check the nutrition labels to see how much vitamin B12 different foods contain.

If your vitamin B12 deficiency isn't caused by a lack of vitamin B12 in your diet, you'll usually need an injection of hydroxocobalamin every three months for the rest of your life.

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

For vitamin B12 injections given in the UK, hydroxocobalamin is preferred to an alternative called cyanocobalamin, because hydroxocobalamin stays in the body for longer. If you need regular injections, cyanocobalamin would have to be given once a month, whereas hydroxocobalamin can be given every three months.

If you need replacement tablets of vitamin B12, however, these will be cyanocobalamin.

To treat folate deficiency anaemia, your doctor will usually prescribe folic acid tablets to be taken every day, so your folate levels build up. They may also give you advice on what to eat, so you take in more folate.

Good sources of folate include:

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

Most people need to take folic acid tablets for about four months. But if the cause behind your folate deficiency anaemia carries on, you may need to take the tablets for longer, possibly for life.

Before you start folic acid, your doctor will check that your vitamin B12 levels are normal. The reason is that folic acid can sometimes ease your symptoms so well that it hides a vitamin B12 deficiency underneath.

If a vitamin B12 deficiency isn't found and treated, it could affect your nervous system.

You may need more blood tests to check that your treatment for vitamin B12 or folate deficiency anaemia is working.

The first test is often done around 10 to 14 days after you start treatment. It checks your haemoglobin level and the number of immature red blood cells (reticulocytes) in your blood. Another blood test may be done after about eight weeks, to confirm the treatment has worked.

If you've been taking folic acid tablets, you may be tested again once the treatment has finished (usually after four months).

Most people who have had a vitamin B12 or folate deficiency won't need further monitoring, unless their symptoms return or the treatment doesn't work. If your doctor feels it's necessary, you may have to come back for a blood test every year to see whether the condition has returned.

Most cases of vitamin B12 deficiency or folate deficiency anaemia can be treated easily and well, so complications are rare. They can still happen now and then, though, especially if you've been short of either vitamin for some time.

Whatever the cause, anaemia can lead to problems with the heart and lungs, because the heart has to work harder to pump oxygen to the organs the body depends on most. 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

A lack of vitamin B12, with or without anaemia, can lead to the following complications:

A lack of vitamin B12 can cause neurological problems, which means problems affecting your nervous system. These include:

• vision problems
• memory loss
• pins and needles (paraesthesia)
• loss of physical coordination (ataxia), which can affect your whole body and cause difficulty speaking or walking
• damage to parts of the nervous system (peripheral neuropathy), particularly in the legs

If neurological problems do develop, they may be irreversible.

Vitamin B12 deficiency can sometimes cause temporary infertility, which means you are unable to conceive. The problem usually gets better once you have the right vitamin B12 treatment.

Pernicious anaemia is a condition where your immune system attacks healthy cells in your stomach. If it has caused your vitamin B12 deficiency, your risk of developing stomach cancer goes up.

If you're pregnant and don't get enough vitamin B12, your baby has a higher risk of a serious birth defect called a neural tube defect. The neural tube is a narrow channel that goes on to form the brain and spinal cord.

Some examples of neural tube defects are:

• 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

A lack of folate, whether or not you have anaemia, can also lead to complications. Some of them are outlined below.

A lack of folate can affect your fertility, just as a lack of vitamin B12 can. The effect is only temporary, though, and folate supplements can usually reverse it.

Research has shown that not having enough folate in your body may raise your risk of cardiovascular disease (CVD). CVD is a general term for a disease of the heart or blood vessels, and coronary heart disease (CHD) is one example.

Studies have found that folate deficiency can raise your risk of some cancers, colon cancer among them.

If you don't get enough folate during pregnancy, your baby may be more likely to be born early (before the 37th week of pregnancy) or to have a low birthweight.

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

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