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There are many different types of vitamin B and they all have important functions.
This section has information on:
Thiamin is also known as vitamin B1. It has several important functions, including:
Thiamin is found in most types of food. Good sources include:
The amount of thiamin you need is:
You should be able to get all the thiamin you need from your daily diet.
Thiamin cannot be stored in the body, so you need it in your diet every day.
There is not enough evidence to know what the effects might be of taking high doses of thiamin supplements each day.
You should be able to get all the thiamin you need by eating a varied and balanced diet. If you take supplements, do not take too much because this might be harmful.
Taking 100mg or less a day of thiamin supplements is unlikely to cause any harm.
Riboflavin is also known as vitamin B2. Its functions include:
Good sources of riboflavin include:
UV light can destroy riboflavin, so ideally these foods should be kept out of direct sunlight.
The amount of riboflavin you need is about:
Riboflavin cannot be stored in the body, so you need it in your diet every day.
You should be able to get all the riboflavin you need from your daily diet.
There is not enough evidence to know what the effects might be of taking high doses of riboflavin supplements each day.
You should be able to get all the riboflavin you need by eating a varied and balanced diet. If you take supplements, do not take too much, because this might be harmful.
Taking 40mg or less a day of riboflavin supplements is unlikely to cause any harm.
Niacin is also known as vitamin B3. It has several important functions, including:
There are two forms of niacin ‐ nicotinic acid and nicotinamide ‐ both of which are found in food.
Good sources of niacin include:
The amount of niacin you need is about:
You should be able to get all the niacin you need from your daily diet.
Niacin cannot be stored in the body, so you need it in your diet every day.
Taking high doses of nicotinic acid supplements can cause skin flushes. Taking high doses for a long time could lead to liver damage.
There is not enough evidence to know what the effects might be of taking high daily doses of nicotinamide supplements.
You should be able to get the amount of niacin you need by eating a varied and balanced diet. If you take niacin supplements, do not take too much because this might be harmful.
Taking 17mg or less of nicotinic acid supplements a day or 500mg or less of nicotinamide supplements a day is unlikely to cause any harm.
Pantothenic acid has several functions, such as helping to release energy from the food we eat.
Pantothenic acid is found in virtually all meat and vegetable foods, including:
Breakfast cereals are also a good source if they have been fortified with pantothenic acid.
You should be able to get all the pantothenic acid you need from your daily diet.
Pantothenic acid cannot be stored in the body, so you need it in your diet every day.
There is not enough evidence to know what the effects might be of taking high daily doses of pantothenic acid supplements.
You should be able to get all the pantothenic acid you need by eating a varied and balanced diet. If you take supplements, do not take too much, as this might be harmful.
Taking 200mg or less a day of pantothenic acid in supplements is unlikely to cause any harm.
Vitamin B6 is also known as pyridoxine. It has several important functions, including:
Vitamin B6 is found in a wide variety of foods, such as:
The amount of vitamin B6 you need is about:
You should be able to get all the vitamin B6 you need from your daily diet.
Taking more than 200mg a day of vitamin B6 for a long time can lead to a loss of feeling in the arms and legs, known as peripheral neuropathy.
Generally, the symptoms are reversible, so once you stop taking supplements, the symptoms usually stop.
However, in a few cases, when people have taken large amounts of vitamin B6, especially for more than a few months, the effect has been irreversible.
Taking doses of 10-200mg a day for short periods may not cause any harm. However, there is not enough evidence to say for how long these doses could be taken safely.
You should be able to get the vitamin B6 you need by eating a varied and balanced diet. If you take vitamin B6 supplements, do not take too much, because this could be harmful.
Do not take more than 10mg of vitamin B6 a day in supplements, unless advised to by a doctor.
Biotin is essential for the metabolism of fat. Very small amounts are needed.
The bacteria that live naturally in your bowel are able to make biotin, so it's not clear if you need any additional biotin from the diet.
Biotin is found naturally in a wide range of foods, but at very low levels compared with other water-soluble vitamins.
There is not enough evidence to know what the effects might be of taking high daily doses of biotin supplements.
You should be able to get all the biotin you need by eating a varied and balanced diet. If you take biotin supplements, do not take too much, as this might be harmful.
Taking 0.9mg or less a day of biotin in supplements is unlikely to cause any harm.
Folic acid, known as folate in its natural form, is one of the B-group vitamins.
Folic acid has several important functions. For example, it:
A lack of folic acid could lead to folate deficiency anaemia.
Folate is found in small amounts in many foods. Good sources include:
Adults need 0.2mg of folic acid a day.
Folic acid cannot be stored in the body, so you need it in your diet every day.
Most people should be able to get the amount they need by eating a varied and balanced diet.
However, if you are pregnant, thinking of trying to have a baby or likely to become pregnant, it is recommended that you take a 0.4mg (400 micrograms) folic acid supplement daily from the time you stop using contraception until the 12th week of pregnancy. This is to help prevent birth defects of the central nervous system, such as spina bifida, in your baby.
If you have a family history of conditions like spina bifida (known as neural tube defects), you may need to take a higher dose of 5mg of folic acid each day until the 12th week of pregnancy. This is available on prescription from your GP. Women with diabetes and those taking anti-epileptic medicines should speak to their GP for advice, as they may also need to take a higher dose of folic acid.
Read more about vitamins and minerals during pregnancy.
Taking doses of folic acid higher than 1mg can disguise vitamin B12 deficiency.
An early symptom of vitamin B12 deficiency is anaemia. However, taking large amounts of folic acid treats the anaemia without treating the B12 deficiency. If a vitamin B12 deficiency is not noticed, it can eventually damage the nervous system.
This is particularly a concern for older people, because it becomes more difficult to absorb vitamin B12 as you get older.
The Department of Health recommends that folic acid supplements are taken by women who are pregnant, thinking of having a baby or likely to become pregnant (see above).
Women who are not pregnant or planning for a baby should be able to get all the folate they need by eating a varied and balanced diet.
If you are taking folic acid supplements, it's important not to take too much, because this could be harmful.
Taking 1mg or less a day of folic acid supplements is unlikely to cause any harm.
Some women have an increased risk of having a pregnancy affected by a neural tube defect, and are advised to take a higher dose of 5mg of folic acid each day until they are 12 weeks pregnant. This is important and unlikely to cause harm, as it is taken on a short-term basis.
Vitamin B12 has several important functions and is involved in:
A lack of vitamin B12 could lead to vitamin B12 deficiency anaemia.
Good sources include:
Adults need approximately 0.0015mg a day of vitamin B12.
If you eat meat, fish or dairy foods, you should be able to get enough vitamin B12 from your diet.
However, because vitamin B12 is not found naturally in foods such as fruit, vegetables and grains, vegans may not get enough of this vitamin. Read our page on the vegan diet for information and advice on vegan nutrition.
There is not enough evidence to show what the effects may be of taking high doses of vitamin B12 supplements each day.
You should be able to get all the vitamin B12 you need by eating a varied and balanced diet. If you take vitamin B12 supplements, do not take too much, because this could be harmful.
Taking 2mg or less a day of vitamin B12 in supplements is unlikely to cause any harm.
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