Supplementary benefits

If you eat a varied and balanced diet, chances are you're already getting the right amount of nutrition to keep your body as healthy as it can be. So why bother with vitamin and mineral supplements, you might ask?

There are all sorts of reasons why you may be deficient in one or more vitamins or minerals - for instance, if you're a smoker you may have low levels of vitamin C, or if you're a woman of childbearing age you may need to top up your iron intake.

Whatever the reason, your pharmacist can help. Meanwhile here's what you need to know about the most important vitamins and minerals...

Vitamin A

What does it do?

Vitamin A keeps your bones, skin, eyesight and immune system healthy. Also known as retinol, it can also be converted in the body from beta carotene, a substance called an antioxidant that's found in plants.

Where do you get it?

Vitamin A is only found in animal foods, including liver, cod liver oil, kidney, full-fat dairy products and eggs. But you can get beta carotene from fruit and veg such as spinach, carrots, yellow peppers and mangoes.

Do you need a supplement?

If you suffer from dry skin or eczema, poor night vision or you get frequent colds and infections, you may need more vitamin A - though experts reckon most people can get all they need from their diet. Very high doses, however, can be harmful. You should also never take vitamin A if you're pregnant or planning to conceive. If in doubt, ask your pharmacist for advice.

Vitamin B

What does it do?

B vits include thiamin (B1), riboflavin (B2), niacin (B3 - either nicotinic acid or niacinamide), pantothenic acid (B5), pyridoxine (B6), biotin, cobalamin (B12) and folic acid. Collectively, they help release energy from the food you eat plus keep your heart, brain, nervous system, muscles and skin healthy.

Where do you get it?

From lots of foods, the best sources being wheat, nuts, meat, whole grains, beans, dairy products, yeast and fortified cereals.

Do you need a supplement?

If you eat lots of sugar and refined carbohydrates, drink too much alcohol or smoke, your B levels could be low. Vegetarians and vegans are at risk of vitamin B12 deficiency, which can lead to anaemia. If you're pregnant or thinking of having a baby, on the other hand, health experts recommend taking a daily 400 micrograms supplement of folic acid to help protect against certain birth defects.

Vitamin C

What does it do?

Vitamin C keeps your cells and connective tissue healthy, which explains why you need it for healthy skin and wound healing.

Where do you get it?

From fruit and veg - oranges are best known for their vitamin C content, but top sources include blackcurrants, guava, papaya, kiwi fruit, green peppers, broccoli and strawberries.

Do you need a supplement?

A lack of vitamin C can lead to a condition called scurvy, which is not such a problem in this day and age. However, some people may still be deficient in vitamin C, including the very young and the very old. Smoking is also thought to deplete the amount of vitamin C in your body.

Vitamin D

What does it do?

Vitamin D strengthens your bones and teeth by helping calcium to be used in the body.

Where do you get it?

It's mostly produced in the body when your skin is exposed to sunlight. Food sources include full-fat dairy foods, eggs, cod liver oil and some margarines.

Do you need a supplement?

Vegans might need extra vitamin D, especially during the winter months. If you've been on a low-fat diet for a long time or if you spend most of your time indoors, you could also be missing out. If you're taking any medicines, however, ask your pharmacist for advice.

Vitamin E

What does it do?

Also called tocopherol, vitamin E is important for your heart, immune system, skin and circulation.

Where do you get it?

From vegetable oils, nuts, seeds, beans, avocados, leafy green veg and egg yolk.

Do you need a supplement?

There aren't any particular signs of deficiency. However vitamin E is often used to relieve PMS or period pain, plus dry skin or eczema. Do not, however, take vitamin E with anti-coagulants such as Warfarin or Heparin, and ask your pharmacist for advice if you have diabetes or high blood pressure.

Calcium

What does it do?

Calcium helps to make your bones and teeth strong. It's also essential for healthy nerves and muscles, and for making sure your blood clots normally.

Where do you get it?

Dairy foods such as milk and cheese are good sources of calcium, as are green leafy veg (broccoli and cabbage, but not spinach), tinned fish (with bones), nuts, pulses, tofu, sesame seeds and whole grains.

Do you need a supplement?

Pregnant and breastfeeding women might need more calcium, as well as teenagers and women taking HRT. Not getting enough calcium might put you at risk of developing osteoporosis, so it's important that you get the right amount.

Iron

What does it do?

Iron carries oxygen from your lungs to all the cells of your body - too little of it, and you may develop anaemia, which can make you feel tired and run-down. It's also needed for healthy hair and a strong immune system.

Where do you get it?

Best sources include liver and red meats, but vegetarians can also find it in nuts, dark green vegetables, dried apricots, beans and soya foods.

Do you need a supplement?

Women who are breastfeeding or have heavy periods are susceptible to iron deficiency (vegetarians may also be at risk). Don't drink tea or coffee within an hour of taking an iron supplement, as they affect it's absorption.

Magnesium

What does it do?

Because of the way it works with calcium, magnesium keeps your teeth and bones strong. You also need it for your muscles and nervous system, and for releasing energy from food.

Where do you get it?

Mostly from nuts, dried fruit, whole grains, green vegetables, soya beans and other pulses, plus some seafood.

Do you need a supplement?

If you have heavy or painful periods, a magnesium supplement might help. Cramps, aching muscles and an irregular heart beat are all signs of deficiency.

Selenium

What does it do?

Selenium is necessary for healthy skin, hair, nails and eyes. It also helps regulate your hormone levels and is thought to be important for your immune system.

Where do you get it?

From liver and kidney, fish, shellfish and dairy products. Plant sources include Brazil nuts, bread and blackstrap molasses.

Do you need a supplement?

Many people are thought to have low levels of selenium. Breastfeeding women and dieters are particularly susceptible to selenium deficiency, as are vegetarians and vegans.

Zinc

What does it do?

Keeps your reproductive and immune systems healthy, plus it's good for skin, teeth and bones.

Where do you get it?

Best sources include meat, seafood, bread and nuts. Green vegetables, whole grains, beans and root ginger are good plant sources.

Do you need a supplement?

Yes, if you're breastfeeding or a smoker. If you have dry skin, frequent colds and infections, fertility problems or thinning hair, you may also need extra. Drinking too much tea or coffee may also deplete zinc levels.