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Hot topic - Vitamin supplements

11 October 2004 - written by Bupa's Health information team

Vitamins are vital for good health. Many of us are choosing to take vitamin supplements in our pursuit of a healthier lifestyle. But reports about whether vitamin supplements are good for us are confusing. Below, we look at the issue in more depth.

What are vitamins?

Vitamins are substances that your body needs to work properly and keep you in good health. Most vitamins cannot be made by the body, so they have to be provided by your diet in small regular amounts.1

Why do I need vitamins?

Your body uses vitamins to do a number of things, including building and maintaining tissues and organs. Vitamins provide energy, boost the immune system, keep skin healthy and help keep the brain and nervous system in good working order.2

How can I get my vitamins from my diet?

Vitamins are found in a variety of foods. There are two types - fat-soluble and water-soluble vitamins.

Fat-soluble vitamins are found mainly in some fatty foods such as butter, dairy products, liver and oily fish. If your body does not need fat-soluble vitamins immediately, then they are stored in the liver for future use.3

There are only four fat-soluble vitamins:3

  • vitamin A
  • vitamin D
  • vitamin E
  • vitamin K

Water-soluble vitamins are found in fruits and vegetables. Unlike fat-soluble vitamins, they are not stored in the body, so you need to eat them more often. If your body has too many water-soluble vitamins, then they are removed in your urine when you go to the toilet.3

Examples of water-soluble vitamins include:3

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

Am I getting enough vitamins?

For most healthy people, a varied, balanced diet will provide all of the vitamins your body needs, so supplements are not necessary.

Eating at least five portions of fruit and vegetables a day will provide most of the vitamins you need. The rest come from meat, fish, eggs and dairy products. Seeds and nuts are also a great source of vitamins.1

Each vitamin has a different role in the body so you need different amounts of each. People also need different amounts depending on their age, sex, level of activity and their health.1

For more information about eating a healthy balanced diet, please see our factsheet at http://hcd2.bupa.co.uk/fact_sheets/html/healthy_eating.html"

What happens if I don't get enough vitamins?

If your body doesn't get the right amount of vitamins, you may get certain symptoms. If your body continues to lack vitamins over a long period of time, the symptoms become more severe and you may develop a deficiency disease.1

Should everyone take vitamin supplements?

For most healthy adults, eating a varied, healthy diet provides all the vitamins you need so there is no need for vitamin supplements. It is generally advisable to get your vitamins from your diet rather than supplements.3

It is the mixture of vitamins in food that is beneficial to your health, rather than a high intake of one particular vitamin. Foods are better than supplements because a healthy balanced diet will contain certain other nutrients, such as fibre, which supplements cannot replace.4

However, there are some people who should take vitamin supplements.

Who should take vitamin supplements?

Some people need vitamin supplements, either because they have increased requirement or because it is likely that their diet will not provide enough. Experts advise the following people to take vitamin supplements:

  • Pregnant women
    Women who are or might become pregnant are advised to take 400 micrograms of folic acid a day and to eat foods rich in this vitamin. Folic acid has been shown to reduce the risk of unborn babies developing defects.3,4 However, high doses of vitamin A are not recommended for pregnant women or those who might become pregnant because it can lead to abnormal development of the baby in the womb.
  • Children
    The Department of Health recommends that children aged between six months and four years take vitamin A, C and D supplements. Vitamin A is needed for vision and healthy skin, vitamin C protects your bones and body tissues and vitamin D helps with growth and development of bones and teeth.4

Who else might benefit from vitamin supplements?

These groups of people may have a diet that is not meeting their nutritional requirements and may benefit from vitamin supplements:

  • Elderly people, particularly those who live on their own, may find it harder to make healthy meals, and may wish to top up their vitamin intake with a multivitamin supplement. Older people who don't get much sun because they are housebound or covered up for most of the year are advised to take a supplement that includes ten micrograms of vitamin D each day.4
  • Vegetarians and vegans - consider taking vitamin supplements to replace those that are found in meat and dairy products, particularly if it's not possible to substitute meat with high-protein foods such as pulses and beans.
  • People who are chronically ill.
  • People who drink alcohol heavily.4

Which vitamin supplement should I take?

Choose a multivitamin rather than a high dose of any single vitamin. Make sure that it contains at least 200 micrograms of folate (or 400 micrograms for women who are or may become pregnant).5

Avoid taking supplements that contain just one or two specific vitamins or minerals unless your doctor or state-registered dietitian has advised you to. This is because vitamins and minerals work in harmony and an excessive amount of just one can impair the absorption or effectiveness of others. Correct balance is important. There may also be a risk of overdosing. Supplements sometimes contain over ten times the level of vitamins that we need.

Is it possible to overdose on vitamins?

Yes. It can be dangerous to take too many fat-soluble vitamins as these can build up in the body. Taking too many water-soluble vitamins is less harmful because the body can get rid of these easily.

High doses of vitamins over a long period of time can lead to side-effects. Scientists don't know what the risks might be for all vitamins. Some examples of the risks we know about include:

  • Vitamin A - an increased risk of broken bones, which may be permanent.
  • Vitamin B6 - loss of feeling in the arms or legs called peripheral neuropathy, which is usually, though not always, reversible when intake is reduced.
  • Vitamin C - diarrhoea, stomach pains and wind, which is reversible when intake is reduced.9

There is also evidence that taking high doses of antioxidant vitamins A, C and E may increase the risk of cancer.7

I've heard that vitamin supplements protect against cancer. Is this true?

There is no scientific evidence to suggest that taking vitamin supplements protects against cancer. However, eating a healthy, varied diet does.8

Scientists are not sure why eating a healthy, varied diet reduces the risk of cancer. Some think it may be due to the antioxidant nature of some vitamins, including vitamins A, C and E.1 Antioxidants are substances that are thought to "mop up" molecules called free radicals in the body. Free radicals are produced by the body's normal chemical reactions. Free radicals are thought to damage body cells, which may lead to the development of diseases such as cancer. So mopping up free radicals may stop the damage they cause. However, studies looking at vitamin supplements give conflicting evidence for this.7

But most experts agree that vitamins are good for your health, and the best way to help lower your risk of getting cancer is to eat a healthy balanced diet rather than rely on supplements.

Will vitamin supplements protect me against heart disease?

There is evidence that taking a supplement that includes 200 micrograms of folate each day reduces the chance of heart disease in some people.5

Vitamins that are antioxidants are also thought to protect the heart by removing free radicals from the blood. Research suggests that antioxidants may stop the clogging up of arteries that causes heart disease.9

There is not enough evidence to suggest that taking other vitamin supplements will lower your risk of getting heart disease. Eating a balanced diet is a better way to help look after your heart.9

Will vitamin C stop me getting colds?

Vitamin C does not prevent the common cold, but there is some evidence that taking a high-dose (up to 1000mg) supplement may reduce severity of symptoms.10

How can I make sure I get enough vitamins from my diet?

  • Eat at least five portions of fruit and vegetables every day, choosing different varieties as often as possible
  • Include lean meat and oily fish in your diet
  • Steam or grill foods containing water-soluble vitamins as they can be lost in water used for cooking
  • If you snack between meals, choose seeds and nuts rather than high-fat alternatives
  • If you are a vegetarian or a vegan, include high-protein foods such as pulses and beans in your diet2,3

Further information

Bupa resources:

External resources:

References

  1. British Nutrition Foundation (BNF) Information: Vitamins.
    http://www.nutrition.org.uk/information/energyandnutrients/vitamin.html
  2. Tesco Healthy Living: Why do we need vitamins and minerals?
  3. Food Standards Agency (FSA): Vitamins and minerals.
    "http://www.eatwell.gov.uk/healthydiet/nutritionessentials/vitaminsandminerals/"
  4. Bandolier's summary of advice for healthy living.
    http://www.jr2.ox.ac.uk/bandolier/booth/hliving/10steps.html
  5. Food Standards Agency: Vitamins and minerals (accessed on 11/10/2004)
    http://www.eatwell.gov.uk/healthydiet/nutritionessentials/vitaminsandminerals/
  6. Antioxidant supplements for prevention of gastrointestinal cancers: a systematic review and meta-analysis. Goran Bjelakovic et al, The Lancet Vol 364 October 2 2004 1219-1228.
  7. World Cancer Research Fund/American Insitute for Cancer Research report. "Food, Nutrition and the Prevention of Cancer: A Global Perspective". Chapter 8.
    www.aicr.org/research/report.lasso
  8. British Heart Foundation: Any questions: Vitamins.
    http://www.bhf.org.uk/questions/index.asp?secondlevel=370&thirdlevel=513#1936
  9. Douglas RM, Chalker EB, Treacy B. Vitamin C for preventing and treating the common cold (Cochrane Review). In: The Cochrane Library, Issue 3, 2004. Chichester, UK: John Wiley & Sons, Ltd

 

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