The Office of Dietary Supplements, National Institute of Health, US
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Key points about supplements
- In most cases, the best way to get vitamins and minerals for optimal health, and to reduce the risk of developing long-term conditions, is to eat a wide variety of foods rather than take dietary supplements.
- Some vitamin and mineral supplements, however, might be useful for some people.
- Most people can get all the nutrients they need from eating a varied, balanced diet and spending some time in the sun to get vitamin D.
- Taking vitamin and mineral supplements won't make up for a poor diet. The money spent on buying vitamin and minerals supplements is usually better spent on healthy food.
- Fortified food, eg, milk and yoghurt with extra calcium or breakfast cereals with extra iron, can help provide vitamin and mineral supplements with the added benefit of eating nutrient-rich foods.
- Some people do benefit from supplements, however, especially folic acid before and after pregnancy. Lack of folic acid has been linked with birth defects, such as spina bifida.
- You may also need other supplements during pregnancy and breastfeeding, if you are older, have darker skin, menstruate (have periods), have a vegan diet or have certain health conditions that affect absorption from your gut.
- Taking too much of some supplements can be harmful, so always check the label and talk to your doctor, nurse or pharmacist first.
Supplements are manufactured products that are taken orally (by mouth) in a variety of forms, including tablet, liquid, gummies or powders. They aim to increase your intake of certain vitamins, minerals, herbs, amino acids or enzymes you normally get through food, through sources that are either extracted from food or made synthetically (‘man-made’).
The best way to get vitamins and minerals for optimal health and to reduce the risk of developing long-term conditions is to eat a wide variety of foods. Many people worry they don’t get enough vitamins and minerals, so take dietary supplements. But most people should be able to get enough vitamins and minerals from the food they eat. There is often no good evidence of the benefits of taking a dietary supplement, and too much of some nutrients can be harmful.
Eating well from the main food groups each day makes sure you get the best possible spread of nutrients. That’s why the money spent on supplements is often better spent on healthy food. Some foods have extra vitamins and minerals added(external link) during manufacturing. These include bread with folic acid, and breakfast cereals with extra iron and other minerals and vitamins. These products can help increase our vitamin and mineral intake, especially for certain groups like children and pregnant women.
Some vitamin and mineral supplements, however, might be useful for some people.
- Iron deficiency is common in women during childbearing years. Iron supplements may be needed to avoid or treat iron deficiency especially if you don’t eat much red meat, fish or chicken.
- Folic acid is very important for women if a pregnancy is planned and during pregnancy. Lack of folic acid has been linked with birth defects, such as spina bifida.
- Iodine is recommended throughout pregnancy and breastfeeding.
- Vitamin B12 may be needed if you are an older person or if you are vegan (do not eat any food of animal origin).
- Vitamin D may be needed if you are older, have a dark skin, don’t go outside much or wear clothing that covers most of your body.
- Iron, zinc, folate, calcium and fat-soluble vitamin deficiencies are common in people who are newly diagnosed with coeliac disease.
It’s important to talk to your doctor or a dietitian, who will check your levels with a blood test and work with you to make sure you get the right dose and take it for the right amount of time.
Many supplements are simply excreted in your pee. While they may not be doing you much good, they usually are doing little harm. However, you can take too much of some supplements, which puts you at risk of negative effects. This generally only occurs from high dose vitamin and mineral supplement pills or if you exceed the recommended dosage.
While medicines have to be approved before being prescribed, there is no similar regulation system in place for supplements. This means that you can't be sure about the quality of supplements – which can come from all over the world. If you do take supplements, make sure you buy them from a reputable (trusted) source and not from an unknown company on the internet.
The Nutrient Reference Values for Australia and New Zealand(external link) include tables that give safe upper levels of intake for vitamins and minerals. If you choose to take vitamin and mineral supplement pills, check the dose against the table and make sure you are not exceeding it. Remember to also take into account the vitamins and minerals you're getting from the food you're already eating. A doctor or dietitian can help you with this as it can be hard to do.
Dietary supplements can interfere with some medications, so it is important to always tell your healthcare provider about any supplements you are taking.
High protein supplements(external link) Health Promotion Agency, NZ, 2019
- Supplements(external link) Nutrition Foundation, NZ
- Dietary supplements regulations 1985(external link) Parliamentary Counsel Office, NZ
- Vitamins and minerals: dietary sources supplements and deficiencies(external link) BPAC, NZ, 2008
- Dietary advice for people with coeliac disease(external link) BPAC, NZ, 2011
- A focus on nutrition – key findings of the 2008/09 New Zealand adult nutrition survey(external link) University of Otago & Ministry of Health, NZ, 2011
Credits: Healthify Editorial Team. Healthify is brought to you by Health Navigator Charitable Trust.
Reviewed by: Emma Shields, Registered Dietitian, Wellington.
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