HealthInfo Waitaha Canterbury

Overview of dietary supplements

Dietary supplements (also called food supplements or nutritional supplements) are products designed to give you nutrients that might be missing from your diet.

You might also take them to manage or treat a health condition.

Supplements are available in a variety of forms including tablets, capsules, liquids, gummies and powders.

Popular supplements include:

• vitamins such as multivitamins, vitamins D, C and B12
• minerals such as iron, calcium and magnesium
• herbs such echinacea, St John's wort and turmeric
• protein powders such as whey protein, pea protein and soy protein
• products such as glucosamine, probiotics and fish oils.

Food is usually better than supplements

Most people can get all the nutrients they need from eating a wide variety of healthy food and spending some time in the sun to get vitamin D. Taking supplements will not make up for eating poorly. The money spent buying supplements is usually better spent on healthy food.

Some people may benefit from taking supplements

Some supplements might be useful for some people. These include:

• an iron supplement if you have low iron or iron deficiency anaemia
• folic acid if you're planning to get pregnant and until you’re 12 weeks pregnant
• iodine if you're pregnant or breastfeeding
• a probiotic if you're taking a long course or repeated courses of antibiotics
• vitamin B12 if you're vegan or older with a poor appetite
• vitamin D if you spend most of your time indoors, have dark skin, are pregnant or breastfeeding or cover most of your skin when outside
• iron, folic acid and vitamin D if you have newly diagnosed coeliac disease
• oral nutrition supplement drink if you're underweight and struggling to put weight back on by eating normally
• omega-3 fish oils if you have high triglycerides (a type of fat) in your blood.

Natural is not always better

Supplements including herbal supplements aren't necessarily safer than prescription medicines just because they come from nature. In fact, several prescription medicines are chemicals that were found in nature and purified. Although many supplements are advertised as natural, their ingredients aren't necessarily natural to the human body. Some may even have serious or unpleasant side effects.

Side effects

You're most likely to have side effects from supplements if you take them at high doses or if you take many different supplements. Some supplements can increase the risk of bleeding or, if taken before surgery can change your response to the anaesthetic. Supplements can also interact with some medicines in ways that might cause problems. For example, vitamin K can reduce the ability of the blood thinner warfarin to prevent your blood from clotting.

Tips for choosing and taking a supplement

• Make sure you really need the supplement. Talk to your general practice team, dietitian or pharmacist first.
• Always buy supplements from a reputable source such as your local pharmacy or supermarket, and not from an unknown company on the internet.
• Check the label. It should tell you how much to take, when to take and how often. It should also have an expiry date.

  HealthInfo recommends the following pages

• National Center for Complementary and Integrative Health:
  • Herbs at a glance

    Brief factsheets with basic information about specific herbs or botanicals.

  • Natural doesn't necessarily mean safer or better

    Information about why not all products from nature have been shown to be effective.

Written by HealthInfo clinical advisers. Page created April 2023.

Sources

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Review key: HIHEI-34305