Supplements and cancer

Supplements are products that contain added nutrients – such as vitamins or minerals – that people take in addition to their regular diet. They’re usually taken in tablet or capsule form.

Dietary supplements usually refer to vitamins or minerals which can also be found in foods, but they may include other components of foods. For example:

• phytochemicals (natural plant chemicals that help fight infections)
• lycopene (found in tomatoes)
• herbs and plant materials such as ginseng, garlic and green tea

Dietary supplements are often in doses that are a lot higher than what can be absorbed from foods in a typical diet.

Are fortified products the same as supplements?

Certain groups may need to choose fortified products to meet their nutritional needs. For example, if you follow a vegan diet, it’s important to choose plant-based foods, like plant milks and tofu, that are fortified with calcium to ensure you’re getting enough in your diet. This is different from taking supplements, as fortified foods have nutrients added during their production to improve their overall nutrient content, while supplements are concentrated forms of specific nutrients taken separately.

Can supplements prevent cancer?

Some manufacturers may claim they do, but our research shows that there is no benefit of taking supplements for cancer prevention.

For most people, eating a healthy, balanced diet rich in fruit, vegetables, pulses (such as chickpeas) and wholegrains (such as brown rice) is more likely to protect against cancer. It will also meet your nutritional needs overall without dietary supplements.

Whole foods give more than just vitamins and minerals – they also contain other nutrients such as fibre, which is good for bowel health, maintaining a healthy weight and lowering the risk of bowel cancer.

Our research does show that calcium supplementation may protect against bowel cancer. However, we do not encourage relying on supplements. Instead, we always recommend eating a healthy, balanced diet.

Our Recommendation is: Do not use supplements for cancer prevention.

Can supplements cause cancer?

Some supplements give you a much higher dose of nutrients than you would normally get from eating food alone. In some cases, these high doses can be harmful.

We have strong evidence to show that high-dose beta-carotene supplements can increase the risk of lung cancer in current and former smokers. There’s no evidence they affect the general population.

Who may benefit from taking a supplement?

Most people can get the nutrients they need by eating a healthy, balanced diet.

But some governments, including in the UK, recommend that we should all take a 10 microgram (mcg) vitamin D supplement in the autumn and winter months as our body cannot make enough vitamin D from the sunlight during this period.

Different countries have different guidance. For information in the UK, visit the NHS website.

Certain people may benefit from taking supplements, including:

• Older people with poor appetites.
• Women of childbearing age and new mothers.
• Young children under five.
• People with darker skin or low sunlight exposure.
• Individuals with bowel diseases or those undergoing cancer treatment.

However, it’s important to check with your GP before starting any new supplements to determine if they are necessary.