Browse Health A-Z

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

Vitamins, minerals and supplements

 

Vitamins and minerals are essential nutrients that your body needs in small amounts to work properly.

Most people should be able to get all the nutrients they need by eating a varied and balanced diet. If you choose to take vitamin and mineral supplements, be aware that taking too much or taking them for too long can cause harmful effects.

The pages in this section contain all the advice and information that adults need about the vitamins, minerals and trace elements that are essential for health, including: 

  • what they do
  • how much you need
  • what happens if you have too much
  • safety advice about supplements 

What are vitamins?

There are two types of vitamins: fat-soluble and water-soluble.

Fat-soluble vitamins

Fat-soluble vitamins are found mainly in fatty foods such as animal fats including butter and lard, vegetable oils, dairy foods, liver and oily fish.

While your body needs these vitamins every day to work properly, you do not need to eat foods containing them every day.

This is because, if your body does not need these vitamins immediately, it stores them in your liver and fatty tissues for future use. These stores can build up so they are there when you need them. However, if you have much more than you need, fat-soluble vitamins can be harmful.

Fat-soluble vitamins are:

Water-soluble vitamins

Water-soluble vitamins are not stored in the body, so you need to have them more frequently.

If you have more than you need, your body gets rid of the extra vitamins when you urinate. Because the body does not store water-soluble vitamins, these vitamins are generally not harmful.

Water-soluble vitamins are found in fruit, vegetables and grains. Unlike fat-soluble vitamins, they can be destroyed by heat or by being exposed to the air. They can also be lost in water used for cooking.

This means that by cooking foods, especially boiling them, we lose many of these vitamins. The best way to keep as much of the water-soluble vitamins as possible is to steam or grill these foods, rather than boil them.

Water-soluble vitamins are vitamin C, the B vitamins and folic acid.

What are minerals?

Minerals are necessary for three main reasons:

  • building strong bones and teeth
  • controlling body fluids inside and outside cells
  • turning the food you eat into energy

You need minerals in the form they are found in food.

Minerals are found in varying amounts in foods such as meat, cereals including cereal products such as bread, fish, milk and dairy foods, vegetables, fruit (especially dried fruit) and nuts.

Essential minerals include calcium and iron.

What are trace elements?

Trace elements are also essential nutrients that your body needs to work properly, but in much smaller amounts than vitamins and minerals.

Trace elements are found in small amounts in a variety of foods such as meat, fish, cereals, milk and dairy foods, vegetables and nuts.

Examples of trace elements are fluoride and iodine.

Vitamin A is also known as retinol. It has several important functions, such as:

  • strengthening immunity against infections
  • helping vision in dim light
  • keeping skin and the linings of some parts of the body, such as the nose, healthy

Good sources of vitamin A

Good sources of vitamin A include:

  • cheese
  • eggs
  • oily fish, such as mackerel
  • milk
  • fortified low-fat spreads
  • yoghurt

Liver is a particularly rich source of vitamin A. Do not eat liver if you are pregnant (see box, right).

How much vitamin A do I need?

The amount of vitamin A adults need is:

  • 0.7mg a day for men
  • 0.6mg a day for women

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

Any vitamin A that your body does not need immediately is stored for future use. This means you do not need it every day.

What happens if I take too much vitamin A?

According to some research, having more than an average of 1.5mg a day of vitamin A over many years may affect your bones, making them more likely to fracture when you are older.

Older people, particularly women, are already at risk of osteoporosis. This is where your bone density reduces and you have a higher risk of fractures.

If you eat liver or liver pâté once a week, you may be getting more than a daily average of 1.5mg of vitamin A.

If you do not get enough vitamin D, you could be more at risk of the harmful effects of too much vitamin A. People who may be particularly short of vitamin D include:

  • all pregnant and breastfeeding women
  • all people aged 65 and over
  • people who are not exposed to much sun, for example those who cover up their skin for cultural reasons, or those who are housebound or confined indoors for long periods
  • people with darker skin such as people of African-Caribbean and South Asian origin

Many multivitamins contain vitamin A. Other supplements, such as fish liver oil, are also high in vitamin A. If you take supplements containing vitamin A, make sure your daily intake of vitamin A from food and supplements does not exceed 1.5mg. If you eat liver every week, do not take supplements that contain vitamin A.

If you are pregnant, do not take multivitamins containing vitamin A.

If you are pregnant or thinking of having a baby:

  • Do not take supplements containing vitamin A, including fish liver oil, except if you are advised to by your GP
  • Do not eat liver or liver products, such as pâté, because these are very high in vitamin A

Women who have been through the menopause and older men, who are more at risk of osteoporosis, should avoid having more than 1.5mg of vitamin A a day from food and supplements. This means:

  • not eating liver or liver products, such as pâté, more than once a week, or having smaller portions of these
  • taking no more than 1.5mg of vitamin A a day in supplements (including fish liver oil) if you do not eat liver or liver products
  • not taking any supplements containing vitamin A (including fish liver oil) if you eat liver once a week

Having an average of 1.5mg a day or less of vitamin A from diet and supplements combined is unlikely to cause any harm.



If you are pregnant

Having large amounts of vitamin A can harm your unborn baby. Therefore, if you are pregnant or thinking of having a baby, do not eat liver or liver products, such as pâté, because these are very high in vitamin A.

Also, do not take supplements that contain vitamin A. Ask your GP or midwife if you would like more information. 

This section has information on:

  • vitamin B6
  • vitamin B12
  • niacin (vitamin B3)
  • pantothenic acid
  • riboflavin (vitamin B2)
  • thiamin (vitamin B1)
  • folic acid (one of the B-group vitamins)

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
  • chicken
  • turkey
  • cod
  • 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, or taking large amounts 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.

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
  • yeast extract
  • 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.

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.

Taking 2mg or less a day of vitamin B12 in 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

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.

If you take supplements, do not take too much because this might be harmful.

Taking 200mg or less a day of pantothenic acid in 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
  • producing steroids and red blood cells

Good sources of riboflavin

Good sources of riboflavin include:

  • milk
  • eggs
  • fortified breakfast cereals
  • rice
  • mushrooms

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.

Taking 40mg or less a day of riboflavin supplements is unlikely to cause any harm.

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:

  • pork
  • vegetables
  • milk
  • cheese
  • peas
  • fresh and dried fruit
  • eggs
  • wholegrain breads
  • some fortified breakfast cereals

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.

Taking 100mg or less a day of thiamin supplements is unlikely to cause any harm.

Folic acid

Folic acid, known as folate in its natural form, is one of the B-group vitamins.

Folate 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 folate could lead to folate deficiency anaemia.

Good sources of folate

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

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

How much folate do I need?

Adults need 0.2mg of folate a day.

Folate 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 having a baby, take a daily 0.4mg (400 microgram) of folic acid supplement 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.

Women who have had a pregnancy affected by a neural tube defect 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.

Taking a high dose of folic acid can cause..

If you do not get enough vitamin B12, taking doses of folic acid higher than 1mg can disguise the effects of this.

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.

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 (1,000 micrograms) or less a day of folic acid supplements is unlikely to cause any harm.



Vitamin C is also know as ascorbic acid. It has several important functions. For example, it:

  • helps protect cells and keeps them healthy
  • is necessary for the maintenance of healthy connective tissue, which gives support and structure for other tissue and organs 

A lack of vitamin C can lead to scurvy.

Good sources of vitamin C

Vitamin C is found in a wide variety of fruit and vegetables. Good sources include:

  • peppers
  • broccoli
  • brussel sprouts
  • sweet potatoes
  • oranges
  • kiwi fruit

How much vitamin C do I need?

Adults need 40mg of vitamin C a day.

Vitamin C cannot be stored in the body, so you need it in your diet every day.

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

What happens if I take too much vitamin C?

Taking large amounts of vitamin C can cause:

  • stomach pain
  • diarrhoea
  • flatulence

These symptoms should disappear once you stop taking vitamin C supplements.

Taking 1,000mg or less a day of vitamin C supplements is unlikely to cause any harm.



Vitamin D has several important functions. For example, it helps regulate the amount of calcium and phosphate in the body. These substances are needed to keep bones and teeth healthy.

If you do not get enough vitamin D, you might be more at risk of some of the harmful effects of too much vitamin A. Ask your GP for more information.

A lack of vitamin D can also lead to rickets.

Good sources of vitamin D

Most of our vitamin D comes from sunlight on our skin. The vitamin forms under the skin in reaction to sunlight. The best source is summer sunlight. However, if you are out in the sun, take care not to turn red or get burnt.

Vitamin D is also found in a small number of foods. Good food sources are:

  • oily fish, such as salmon and sardines
  • eggs
  • fortified fat spreads
  • fortified breakfast cereals
  • powdered milk

How much vitamin D do I need?

You do not need vitamin D in your diet every day. This is because any of the vitamin your body does not need immediately is stored for future use.

However, the Food Safety Authority and the Health Service Executive recommend that all babies 0 to 12 months should receive a vitamin D supplement.Vitamin D3 is the preferred form of the supplement for infants. Products which contain other vitamins as well as vitamin D should not be used.

What happens if I take too much vitamin D?

Taking high doses of vitamin D for long periods of time could weaken your bones.

Most people should be able to get the vitamin D they need by eating a varied and balanced diet and by getting some sun. If you take vitamin D supplements, do not take too much.

Taking 25 micrograms (0.025mg) or less a day of vitamin D supplements is unlikely to cause any harm.



Vitamin E has several important functions. For example, it helps protect cell membranes.

Good sources of vitamin E

Vitamin E is found in a wide variety of foods. The richest sources are plant oils such as soya, corn and olive oil.

Other good sources include:

  • nuts and seeds
  • wheat germ, found in cereals and cereal products

How much vitamin E do I need?

The amount of vitamin E you need is:

  • 4mg a day for men
  • 3mg a day for women

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

Any vitamin E that your body does not need immediately is stored for future use, so you do not need it in your diet every day.

What happens if I take too much vitamin E?

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

If you take vitamin E supplements, do not to take too much. Taking 540mg or less a day of vitamin E supplements is unlikely to cause any harm.



Vitamin K has several important functions. For example, it is needed for blood clotting, which means it helps wounds heal properly.

There is increasing evidence that vitamin K is also needed to help build strong bones.

Good sources of vitamin K

Vitamin K is found in:

  • green leafy vegetables, such as broccoli and spinach
  • vegetable oils
  • cereals

Small amounts can also be found in meat and dairy foods.

As well as getting vitamin K from food, we also get it from our own bodies as it is produced by bacteria in the bowel.

How much vitamin K do I need?

Adults need approximately 0.001mg a day of vitamin K for each kilogram of their body weight.

For example, someone who weighs 65kg would need 0.065mg a day of vitamin K, while a person who weighs 75kg would need 0.075mg a day.

You should be able to get all the vitamin K you need by eating a varied and balanced diet.

Any vitamin K that your body does not need immediately is stored in the liver for future use, so you do not need it in your diet every day.

What happens if I take too much vitamin K?

There is not enough evidence to know what the effects might be of taking high doses of vitamin K supplements each day. If you take vitamin K supplements, do not take too much because this might be harmful.

Taking 1mg or less of vitamin K supplements a day is unlikely to cause any harm.



Calcium has several important functions, including:

  • helping build strong bones and teeth
  • regulating muscle contractions, including heartbeat 
  • ensuring blood clots normally

It is thought that calcium may help lower high blood pressure and protect against colon and breast cancer, although more evidence is needed to confirm this.

A lack of calcium could lead to a condition called rickets.

Good sources of calcium

Good sources of calcium include:

  • milk, cheese and other dairy foods
  • green leafy vegetables, such as broccoli, cabbage and okra, but not spinach
  • soya beans
  • tofu
  • soya drinks with added calcium
  • nuts
  • bread and anything made with fortified flour
  • fish where you eat the bones, such as sardines and pilchards

How much calcium do I need?

Adults need 700mg of calcium a day.

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

What happens if I take too much calcium?

Taking high doses of calcium could lead to stomach pain and diarrhoea.

. If you take calcium supplements, do not take too much.Taking 1,500mg or less a day of calcium supplements is unlikely to cause any harm.



Iodine helps make the thyroid hormones. These hormones help keep cells and the metabolic rate healthy.

Good sources of iodine

Iodine is a trace element found in seawater, rocks and some types of soil. Good food sources include sea fish and shellfish.

Iodine can also be found in plant foods such as cereals and grains, but the levels vary depending on the amount of iodine in the soil where the plants are grown.

 

How much iodine do I need?

Adults need 0.14mg of iodine a day.

You should be able to get all the iodine you need by eating a varied and balanced diet.

What happens if I take too much iodine?

Taking high doses of iodine for long periods of time could change the way your thyroid gland works. This can lead to a wide range of different symptoms, such as weight gain.

. If you take iodine supplements, do not take too much because this could be harmful.

Taking 0.5mg or less a day of iodine supplements is unlikely to cause any harm.



Iron is an essential mineral that has several important roles in the body. For example, it helps make red blood cells, which carry oxygen around the body.

A lack of iron can lead to iron deficiency anaemia.

Good sources of iron

Good sources of iron include:

  • liver
  • meat
  • beans
  • nuts
  • dried fruit, such as dried apricots
  • wholegrains, such as brown rice
  • fortified breakfast cereals
  • soybean flour
  • most dark-green leafy vegetables, such as watercress and curly kale

Many people think that spinach is a good source of iron, but spinach also contains a substance that makes it harder for the body to absorb the iron from it.

Similarly, tea and coffee contain a substance that can make it harder for the body to absorb iron. Therefore, cutting down on tea and coffee could help improve your iron levels.

Although liver is a good source of iron, do not eat it if you are pregnant. This is because it is also rich in vitamin A, large amounts of which can damage your unborn baby.

How much iron do I need?

The amount of iron you need is:

  • 8.7mg a day for men
  • 14.8mg a day for women

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

Women who lose a lot of blood during their monthly period may need to take iron supplements. Speak to your GP or a state-registered dietician for more advice.

What happens if I take too much iron?

The side effects of taking high doses of iron include:

  • constipation
  • nausea
  • vomiting
  • stomach pain

Very high doses of iron can be fatal, particularly if taken by children, so always keep iron supplements out of the reach of children.

What does the Department of Health advise?

Most people should be able to get all the iron they need by eating a varied and balanced diet. If you take iron supplements, do not take too much because this could be harmful.

Taking 17mg or less a day of iron supplements is unlikely to cause any harm. However, continue taking a higher dose if advised to by your GP.



This section has information about:

  • beta-carotene
  • boron
  • chromium
  • cobalt
  • copper
  • magnesium
  • manganese
  • molybdenum
  • nickel
  • phosphorus
  • potassium
  • selenium
  • silicon
  • sodium chloride (salt)
  • sulphur
  • zinc

Beta-carotene

Beta-carotene gives yellow and orange fruit and vegetables their colour. It is turned into vitamin A in the body, so it can perform the same functions in the body as vitamin A.

Good sources of beta-carotene

The main food sources of beta-carotene are:

  • yellow and green (leafy) vegetables, such as spinach, carrots and red peppers
  • yellow fruit such as mango, melon and apricots

How much beta-carotene do I need?

You should be able to get the amount of beta-carotene you need from your daily diet.

What happens if I take too much beta-carotene?

Beta-carotene supplements have been found to increase the risk of lung cancer developing in smokers and in people who have been heavily exposed to asbestos at work.

It is possible that taking large amounts of beta-carotene supplements would also increase the risk of cancer in other people.

Some research suggests that having large amounts of vitamin A over a long time may affect people's bones and make them more likely to fracture when they are older. However, beta-carotene does not have this effect. This is because the body's conversion of beta-carotene into vitamin A is not very efficient, so it is unlikely to result in high levels of vitamin A in the body.

What does the Department of Health advise?

You should be able to get the amount of beta-carotene you need by eating a varied and balanced diet. If you decide to take beta-carotene supplements, it is important not to take too much because this could be harmful.

Do not take more than 7mg of beta-carotene supplements a day. However, continue taking a higher dose if advised to do so by a doctor.

People who smoke or who have been exposed to asbestos are advised not to take any beta-carotene supplements.

There is no evidence that the beta-carotene we get from food is harmful.

Boron

Boron is a trace element. It is thought to help the body make use of glucose, fats, oestrogen and other minerals, such as calcium, copper and magnesium, in the food we eat.

Good sources of boron

Boron is found widely in the environment, in the oceans, rocks, soils and plants. Food sources of boron include:

  • green vegetables
  • fruit
  • nuts

How much boron do I need?

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

What happens if I take too much boron?

Taking high doses of boron for long periods may reduce fertility in men.

What does the Department of Health advise?

You should be able to get all the boron you need by eating a varied and balanced diet. If you take supplements containing boron, do not take too much because this could be harmful.

Taking 6mg or less of boron supplements a day is unlikely to cause any harm.

Chromium

Chromium is a trace element that is thought to influence how the hormone insulin behaves in the body. This means that chromium may affect the amount of energy we get from food.

Good sources of chromium

Chromium is found widely in the environment, in the air, water and soil, and in plants and animals.

Good food sources of chromium include:

  • meat
  • wholegrains, such as wholemeal bread and whole oats
  • lentils
  • spices

How much chromium do I need?

Adults need at least 0.025mg of chromium a day.

You should be able to get all the chromium you need by eating a varied and balanced diet.

What happens if I take too much chromium?

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

What does the Department of Health advise?

You should be able to get all the chromium you need by eating a varied and balanced diet.

If you take chromium supplements, do not take too much because this might be harmful.

Having 10mg or less a day of chromium from food and supplements is unlikely to cause any harm.

Cobalt

Cobalt is a trace element that forms part of the structure of vitamin B12.

Good sources of cobalt

Cobalt is found widely in the environment. Good food sources of cobalt include:

  • fish
  • nuts
  • green leafy vegetables, such as broccoli and spinach
  • cereals, such as oats

How much cobalt do I need?

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

Cobalt is a major part of the structure of vitamin B12. Therefore, if you get enough vitamin B12, you will also get enough cobalt.

Adults need approximately 0.0015mg (1.5 micrograms) of vitamin B12 a day.

What happens if I take too much cobalt?

Having high amounts of cobalt for long periods of time could affect the heart and might decrease fertility in men.

What does the Department of Health advise?

Having too much cobalt could be harmful. However, cobalt is currently not used in supplements in the UK and the amount we get from food is not harmful.

Having 1.4mg or less a day of cobalt supplements is unlikely to cause any harm.

Copper

Copper is a trace element that has several important functions. For example, it:

  • helps produce red and white blood cells and triggers the release of iron to form haemoglobin, the substance that carries oxygen around the body
  • is thought to be important for infant growth, brain development, the immune system and strong bones

Good sources of copper

Good sources of copper include:

  • nuts
  • shellfish
  • offal

How much copper do I need?

Adults need 1.2mg of copper a day.

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

What happens if I take too much copper?

Taking high doses of copper could cause:

  • stomach pain
  • sickness
  • diarrhoea
  • damage to liver and kidneys if taken for a long time

What does the Department of Health advise?

You should be able to get all the copper you need by eating a varied and balanced diet. If you take copper supplements, do not take too much because this could be harmful.

Having 1mg or less a day of copper supplements is unlikely to cause any harm.

Magnesium

Magnesium is a mineral that:

  • helps turn the food we eat into energy
  • helps make sure the parathyroid glands, which produce hormones important for bone health, work normally

Good sources of magnesium

Magnesium is found in a wide variety of foods. The richest sources are:

  • green leafy vegetables, such as spinach
  • nuts

Good sources include:

  • bread
  • fish
  • meat
  • dairy foods

How much magnesium do I need?

The amount of magnesium you need is:

  • 300mg a day for men
  • 270mg a day for women

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

What happens if I take too much magnesium?

Taking high doses of magnesium for a short time can cause diarrhoea.

There is not enough evidence to say what the effects might be of taking high doses of magnesium for a long time.

What does the Department of Health advise?

You should be able to get all the magnesium you need by eating a varied and balanced diet. If you take magnesium supplements, do not take too much because this could be harmful.

Having 400mg or less a day of magnesium from supplements is unlikely to cause any harm.

Manganese

Manganese is a trace element that helps make and activate some of the enzymes in the body.

Good sources of manganese

Manganese is found in:

  • tea, which is probably the biggest source of manganese for many people
  • bread
  • nuts
  • cereals
  • green vegetables, such as peas and runner beans

How much manganese do I need?

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

What happens if I take too much manganese?

Taking high doses of manganese for long periods of time might cause nerve damage and neurological symptoms, such as fatigue and depression.

What does the Department of Health advise?

You should be able to get all the manganese you need by eating a varied and balanced diet. If you take manganese supplements, do not take too much because this could be harmful.

For most people, taking 4mg or less of manganese supplements a day is unlikely to cause any harm.

For older people, taking 0.5mg or less of manganese supplements a day is unlikely to cause any harm. This is a lower amount because older people may be more sensitive to manganese.

Molybdenum

Molybdenum is a trace element that helps make and activate some of the enzymes involved in repairing and making genetic material.

Good sources of molybdenum

Molybdenum is found in a wide variety of foods. Foods that grow above ground tend to be higher in molybdenum than meat and foods that grow below the ground, such as potatoes.

Foods particularly high in molybdenum include:

  • nuts
  • tinned vegetables
  • cereals, such as oats

Other sources include:

  • peas
  • leafy vegetables, including broccoli and spinach
  • cauliflower

How much molybdenum do I need?

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

What happens if I take too much molybdenum?

There is some evidence that taking molybdenum supplements might cause joint pain.

What does the Department of Health advise?

You should be able to get all the molybdenum you need by eating a varied and balanced diet. The molybdenum we get from food is not likely to be harmful.

Nickel

Nickel is a trace element that:

  • influences the amount of iron our bodies absorb from foods
  • may be important in helping make red blood cells

Good sources of nickel

Nickel is found widely in the environment. Good food sources include:

  • lentils
  • oats
  • nuts

How much do I need?

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

What happens if I take too much nickel?

Up to 10% of people may have an allergy to nickel that causes a skin rash.

This is usually caused by jewellery or coins that contain nickel, but nickel in food or supplements can also cause a rash if you have this allergy.

What does the Department of Health advise?

You should be able to get all the nickel you need by eating a varied and balanced diet.

If you take nickel supplements, which usually means having nickel without food and on an empty stomach, more nickel will be absorbed.

Therefore, if you are allergic to nickel or think you might be, avoid taking nickel supplements.

The nickel found naturally in food should not cause any harm.

Phosphorus

Phosphorus is a mineral that:

  • helps build strong bones and teeth
  • helps release energy from food

Good sources of phosphorus

Phosphorus is found in:

  • red meat
  • dairy foods
  • fish
  • poultry
  • bread
  • rice
  • oats

How much phosphorus do I need?

Adults need 550mg of phosphorus a day.

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

What happens if I take too much phosphorus?

Taking high doses of phosphorus supplements for a short time can cause diarrhoea or stomach pain.

Taking high doses for a long time can reduce the amount of calcium in the body, which means bones are more likely to fracture.

What does the Department of Health advise?

You should be able to get all the phosphorus you need by eating a varied and balanced diet. If you take phosphorus supplements, it is important not to take too much because this could be harmful.

Taking 250mg or less a day of phosphorus supplements is unlikely to cause any harm.

Potassium

Potassium is a mineral that has many important functions, including:

  • controlling the balance of fluids in the body
  • possibly helping lower blood pressure

Good sources of potassium

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

  • fruit, such as bananas
  • vegetables
  • pulses
  • nuts and seeds
  • milk
  • fish
  • shellfish
  • beef
  • chicken
  • turkey
  • bread

How much potassium do I need?

Adults need 3,500mg of potassium a day. You should be able to get all the potassium you need from your daily diet.

What happens if I take too much potassium?

Taking too much potassium can cause stomach pain, nausea and diarrhoea.

What does the Department of Health advise?

You should be able to get all the potassium you need by eating a varied and balanced diet. If you take potassium supplements, do not take too much because this could be harmful.

Taking 3,700mg or less of potassium supplements a day is unlikely to cause any harm.

However, older people may be more at risk of harm from potassium. This is because as we get older, our kidneys may become less able to remove potassium from our blood. Therefore, older people should not have potassium supplements unless advised to take them by a doctor.

Selenium

Selenium is a trace element that plays an important role in our immune system's function and in reproduction. It also helps prevent damage to cells and tissues.

Good sources of selenium

Selenium is found widely in the environment. Good food sources include:

  • brazil nuts
  • bread
  • fish
  • meat
  • eggs

How much do I need?

The amount of selenium you need is:

  • 0.075mg a day for men
  • 0.06mg a day for women

If you eat meat, fish or nuts, you should be able to get all the selenium you need from your daily diet.

What happens if I take too much selenium?

Too much selenium causes selenosis, a condition that in its mildest form can lead to loss of hair, skin and nails.

What does the Department of Health advise?

You should be able to get all the selenium you need by eating a varied and balanced diet that includes meat, fish or nuts. If you take selenium supplements, it is important not to take too much because this could be harmful.

Taking 0.35mg or less a day of selenium supplements is unlikely to cause any harm.

Silicon

Silicon is a mineral that has two main functions. It:

  • helps keep bones healthy
  • helps keep connective tissues healthy (connective tissue gives support and structure to other tissue and organs) 

Good sources of silicon

Silicon is found in high levels in grains such as oats, barley and rice. It is also found in fruit and vegetables.

How much silicon do I need?

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

What happens if I take too much silicon?

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

What does the Department of Health advise?

You should be able to get all the silicon you need by eating a varied and balanced diet. If you take silicon supplements, it is important not to take too much because this might be harmful.

Taking 700mg or less of silicon supplements a day is unlikely to cause any harm.

Sodium chloride (salt)

Sodium chloride is commonly known as salt. Sodium and chloride both help keep the level of fluids in the body balanced.

Chloride helps the body digest food because it is an essential component of the juices in the stomach and intestines.

Sources of salt

Salt is found naturally at low levels in all foods, but some salt is added to many processed foods such as:

  • ready meals
  • meat products, such as bacon
  • some breakfast cereals
  • cheese
  • some tinned vegetables
  • some bread
  • savoury snacks

How much salt do I need?

You should have no more than 6g of salt (2.4g of sodium) a day. However, on average people eat 9.5g of salt (about 3.7g of sodium) a day. 

A few practical tips for cutting down on salt include:

  • Check food labels and choose foods with less salt.
  • Choose tinned vegetables and pulses with no added salt.
  • Use sauces, such as soy sauce, sparingly because these are often high in salt.
  • Eat fewer salty snacks, such as crisps and salted nuts.
  • Add less salt when cooking. Use herbs and spices for flavour instead.
  • Choose low-salt stock cubes, or make your own stock.
  • Taste your food first and do not automatically add extra salt.

 

What happens if I have too much salt?

Having too much salt is linked to an increase in blood pressure (hypertension), which raises your risk of a stroke and heart attack.

What does the Department of Health advise?

On average, we eat 3.5g more salt than we should each day.

The Department of Health advises people to cut down on salt and that sodium chloride should not be used in supplements.

Sulphur

Sulphur is a mineral that is involved in many different processes. For example, it helps make tissues such as cartilage.

Sources of sulphur

Sulphur is found naturally in many different forms in all foods. It is also used in the form of sulphates and sulphites as food additives in some processed foods.

How much sulphur do I need?

You can get all the sulphur you need from your daily diet.

What does the Department of Health advise?

You can get all the sulphur you need by eating a varied and balanced diet.

Zinc

Zinc is a trace element that has several important functions. For example it:

  • helps make new cells and enzymes
  • helps us process carbohydrate, fat and protein in food
  • helps with the healing of wounds

Good sources of zinc

Zinc is found widely in the environment. Good food sources of zinc include:

  • meat
  • shellfish
  • milk
  • dairy foods, such as cheese
  • bread
  • cereal products, such as wheat germ.

How much zinc do I need?

The amount of zinc you need is about:

  • 5.5-9.5mg a day for men
  • 4-7mg a day for women

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

What happens if I take too much zinc?

Taking high doses of zinc reduces the amount of copper the body can absorb. This can lead to anaemia and to weakening of the bones.

What does the Department of Health advise?

You should be able to get all the zinc you need by eating a varied and balanced diet. If you take zinc supplements, it is important not to take too much because this could be harmful.

Do not take more than 25mg of zinc supplements a day. However, continue taking a higher dose if advised to by a doctor.




Content provided by NHS Choices www.nhs.uk and adapted for Ireland by the Health A-Z.