What are supplements?

Supplements contain: vitamins; minerals; other components of foods such as lycopene, found in tomatoes; herbs; and plant materials such as ginseng, garlic and green tea, sometimes in high doses. Supplements can be in pill, capsule, powder or liquid form.

Evidence on supplements and cancer prevention is inconsistent. Some studies suggest that high-dose supplements can actually be harmful.1

Because of this, we advise against taking supplements to reduce your cancer risk – instead, aim to meet your nutritional needs by eating a varied, healthy, balanced diet.

Whole foods provide more than just vitamins and minerals. For example they contain fibre, which reduces the risk of bowel cancer. This is another reason supplements shouldn't be used as an alternative to eating well.

Who may benefit?

Most people can meet their nutritional needs by eating a healthy, balanced diet. However, some groups may benefit from taking specific supplements, such as:

  • Frail, older people with a poor appetite
  • Pregnant women and new mothers
  • Children under the age of five
  • People who are ill, or who are receiving or recovering from treatment

In such cases, a doctor, dietitian or specialist nurse will be able to provide individual advice.


  1. World Cancer Research Fund. Supplements and cancer prevention. 2016.