Vitamins and minerals - B vitamins and folic acid 

  • Overview

The B vitamins 

There are many different types of vitamin B and they all have important functions.

This section has information on:

  • thiamin (vitamin B1)
  • riboflavin (vitamin B2)
  • niacin (vitamin B3)
  • pantothenic acid
  • vitamin B6
  • folic acid
  • vitamin B12

Thiamin (vitamin B1)

Thiamin is also known as vitamin B1. It has several important functions, including:

  • working with other B-group vitamins to help break down and release energy from food
  • keeping nerves and muscle tissue healthy

Good sources of thiamin

Thiamin is found in most types of food. Good sources include:

  • vegetables
  • peas
  • fresh and dried fruit
  • eggs
  • wholegrain breads
  • some fortified breakfast cereals
  • liver

How much thiamin do I need?

The amount of thiamin you need is:

  • 1mg a day for men
  • 0.8mg a day for women

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.

What happens if I take too much thiamin?

There is not enough evidence to know what the effects might be of taking high doses of thiamin supplements each day.

What does the Department of Health advise?

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 (vitamin B2)

Riboflavin is also known as vitamin B2. Its functions include:

  • keeping skin, eyes and the nervous system healthy
  • helping the body release energy from carbohydrate

Good sources of riboflavin

Good sources of riboflavin include:

  • milk
  • eggs
  • fortified breakfast cereals
  • rice

UV light can destroy riboflavin, so ideally these foods should be kept out of direct sunlight.

How much riboflavin do I need?

The amount of riboflavin you need is about:

  • 1.3mg a day for men
  • 1.1mg a day for women

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.

What happens if I take too much riboflavin?

There is not enough evidence to know what the effects might be of taking high doses of riboflavin supplements each day.

What does the Department of Health advise?

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 (vitamin B3)

Niacin is also known as vitamin B3. It has several important functions, including:

  • helping produce energy from the foods we eat
  • helping keep the nervous and digestive systems healthy

Good sources of niacin

There are two forms of niacin nicotinic acid and nicotinamide  both of which are found in food.

Good sources of niacin include:

  • meat
  • fish
  • wheat flour
  • maize flour
  • eggs
  • milk

How much niacin do I need?

The amount of niacin you need is about:

  • 17mg a day for men
  • 13mg a day for women

You should be able to get all the niacin you need from your daily diet.

There are two forms of niacin  nicotinic acid and nicotinamide  both of which are found in food. Niacin cannot be stored in the body, so you need it in your diet every day.

What happens if I take too much niacin?

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.

What does the Department of Health advise?

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

Pantothenic acid has several functions, such as helping release energy from the food we eat.

Good sources of pantothenic acid

Pantothenic acid is found in virtually all meat and vegetable foods. Good sources include:

  • chicken
  • beef
  • potatoes
  • porridge
  • tomatoes
  • kidney
  • eggs
  • broccoli
  • wholegrains, such as brown rice and wholemeal bread

Breakfast cereals are also a good source if they have been fortified with pantothenic acid.

How much pantothenic acid do I need?

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.

What happens if I take too much pantothenic acid?

There is not enough evidence to know what the effects might be of taking high daily doses of pantothenic acid supplements.

What does the Department of Health advise?

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

Vitamin B6 is also known as pyridoxine. It has several important functions, including:

  • allowing the body to use and store energy from protein and carbohydrates in food
  • helping form haemoglobin, the substance that carries oxygen around the body

Good sources of vitamin B6 

Vitamin B6 is found in a wide variety of foods such as:

  • pork
  • poultry (such as chicken or turkey)
  • fish
  • bread
  • whole cereals, such as oatmeal, wheat germ and rice
  • eggs
  • vegetables
  • soya beans
  • peanuts
  • milk
  • potatoes
  • some fortified breakfast cereals

How much vitamin B6 do I need?

The amount of vitamin B6 you need is about:

  • 1.4mg a day for men
  • 1.2mg a day for women

You should be able to get all the vitamin B6 you need from your daily diet. You need it in your diet every day because it cannot be stored in the body.

What happens if I take too much vitamin B6?

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.

What does the Department of Health advise?

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.

Folic acid

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:

  • works together with vitamin B12 to form healthy red blood cells
  • helps reduce the risk of central nervous system defects such as spina bifida in unborn babies

A lack of folic acid could lead to folate deficiency anaemia.

Good sources of folic acid

Folic acid is found in small amounts in many foods. Good sources include:

  • broccoli
  • brussels sprouts
  • liver
  • spinach
  • asparagus
  • peas
  • chickpeas
  • brown rice
  • fortified breakfast cereals

How much folic acid do I need?

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 or thinking of trying to have a baby, take a 0.4mg (400 microgram) of 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 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.

Read more about vitamins and minerals during pregnancy.

What happens if I take too much folic acid?

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.

What does the Department of Health advise?

The Department of Health recommends that folic acid supplements are taken by women who are pregnant or thinking of having a baby (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 is 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.

Vitamin B12

Vitamin B12 has several important functions and is involved in:

  • making red blood cells and keeping the nervous system healthy
  • releasing energy from the food we eat
  • processing folic acid

A lack of vitamin B12 could lead to vitamin B12 deficiency anaemia.

Good sources of vitamin B12

These include:

  • meat
  • salmon
  • cod
  • milk
  • cheese
  • eggs
  • some fortified breakfast cereals

How much vitamin B12 do I need?

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 in foods such as fruit, vegetables and grains, vegans may not get enough of this vitamin. See the vegan diet for information and advice about vegan nutrition.

What happens if I take too much vitamin B12?

There is not enough evidence to show what the effects may be of taking high doses of vitamin B12 supplements each day.

What does the Department of Health advise?

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.


Page last reviewed: 26/11/2012

Next review due: 26/11/2014

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Comments

The 5 comments posted are personal views. Any information they give has not been checked and may not be accurate.

polyhedron said on 16 December 2012

The amount of B12 required may be very low (though the 1.5 micrograms a day is at the extremely low end of published requirements.) But taking 2000 micrograms is unlikely to be harmful. That much is quite correct.

Many people have some degree of impairment of their absorption of B12. Low stomach acid from any cause (including medicines such as proton pump inhibitors, H2-agonists or ant-acids) or dysfunction of the parietal cells are classic reasons. These occur all too commonly especially, for example, in those with autoimmune thyroid disease (e.g. Hashimoto's thyroiditis).

Once the usual way of absorbing B12 stops functioning properly, it is necessary to go down the route of using very high dose oral supplements or sub-lingual, nasal sprays, etc. - or injections. That is why these doses are used.

DOes of a few micrograms are only really likely to be of use in people whose diet simply does not have the B12 in it - e.g. vegans.

The pernicious anaemia society is well worth visiting.

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Mars Express said on 14 July 2012

Steve, concerning vitamin B12:

"This 2mg figure is more than 1000 times the recommended 1.5ug. Do you perhaps mean 2ug (MICROgram)?"

All the B vitamins are water soluble and are not stored in the body. If you have too much, you pass it out. The amount of B12 which may be harmful is not known. But that does not mean any amount cannot be harmful.

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Timbob said on 15 June 2012

Re johnross' comments above, it is worth re-iterating that the NCAF (amongst others) also makes the case for good diet, and against supplements...they state their aim thus:-

The National Council Against Health Fraud is a nonprofit, tax-exempt voluntary health agency focused upon health fraud, misinformation, and quackery as public health problems.

check:-

http://www.ncahf.org/pp/supp.html

Quoted from that page...

"To Consumers:
Be aware that supplements cannot change a poor diet into a good one; good nutrition involves more than supplements are apt to supply.
Few people need to, supplement their diets with pills, but if you do choose to supplement, to assure safety do not exceed the Recommended Dietary Allowances for vitamins and minerals.
To assure good nutrition apply the three principles of variety, balance and moderation; use the USDA Food Groups model and USDA/HHS Dietary Guidelines. "

Sorry, but site after site which appears NOT to be linked to selling so-called supplements, say much the same.

You may howver be correct in your assertion that
".....this is total rubbish for most people" but that is more than likely because many people's diet is inadequate or poor.

So how do you suggest these people (and you seem to include yourself amongst them) go about PROPERLY "supplementing" their diet? By downing pills that are the latest fad as promulgated by the worst examples of the populist press?
Going by the reams of inaccurate, badly reported, sloppy and quite probably biased "jounalism" that I have encountered in several newspapers (naming no names!), these kind of sensationalist "miracle cure" type stories are the last place I would go for decent health or dietary information.

So where do you get your information from, that enables you to say:-
"that most people in Britain are seriously deficient.. etc?
Sources please.

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johnross47 said on 26 October 2011

For every single vitamin you say the same thing....you should be able to get all the vitamin x you need by eating a healthy diet.....this is total rubbish for most people....I have actually tracked my diet in detail for a year and I know just how hard it is. I would be prepared to bet a lot of money that most people in Britain are seriously deficient in vit D for a start, and almost certainly vit E and some of the B vits. Most are probably short of calcium and potassium and quite possibly zinc. There is also the issue of why the UK recommendations are so much lower than anyone else's. This web site has been written by a supplement phobic with a fantasy view of the normal diet and ignorance of recent research( on vit D in particular.)

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shimself said on 02 October 2011

B12
you say
Adults need approximately 0.0015mg a day of vitamin B12.
...
What happens if I take too much vitamin B12?
There is not enough evidence to show what the effects may be of taking high doses of vitamin B12 supplements each day.
... 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.

This 2mg figure is more than 1000 times the recommended 1.5ug. Do you perhaps mean 2ug (MICROgram)is "ok"?
And how do you square "too much could be harmful" with "not enough evidence to show"?

Steve

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