One in two people in the UK will be affected by cancer at some point in their lives. The important new expert report by the World Cancer Research Fund (WCRF) has been published, evaluating the links between diet, nutrition, physical activity and cancer and the past decade of cancer prevention research.

It finds that around 40% of cancers could be prevented by making healthy lifestyle choices.

Here’s a summary of the key findings, along with WCRF recommendations about how we can best help prevent cancer.

Key lifestyle factors linked to cancer

1. Body fatness

• There is strong evidence that greater body fatness is a cause of many cancers – including pancreatic cancer, liver cancer and ovarian cancer. Science in relation to the link has grown over the last decade.Rates of overweight and obesity have been rising in most countries. Figures released on obesity just this week show that in the UK almost 60% more children in their last year of primary school are classified as ‘severely obese’ than in their first year.WCRF says that if current trends continue, being overweight or obese is likely to overtake smoking as the number one risk factor for cancer.

• Whilst greater weight gain in adulthood increases the risk of post-menopausal breast cancer, evidence showed that being overweight or obese as an adult before menopause decreases the risk of pre-menopausal breast cancer. Also, being overweight or obese between the ages of 18 and 30 years decreased the risk of pre- and postmenopausal breast cancer.Despite the findings, it is important to know that WCRF recommend maintaining a healthy weight throughout all stages of life.

WCRF Expert Panel opinion – Keep weight within the healthy BMI range (18.5kg/m2 – 24.9kg/m2) and avoid weight gain in adult life. WCRF explain more about BMI and provide a useful BMI calculator.

2. Dietary factors

a. Wholegrains, vegetables and fruit

• Wholegrains and other foods containing dietary fibre decrease the risk of colorectal cancer. This includes both foods that naturally contain fibre and foods that have had fibre added.
• Beta-carotene in foods or supplements is unlikely to have a substantial effect on the risk of prostate cancer.
• Foods contaminated by aflatoxins (toxins found in some fungi) increase the risk of liver cancer. Find out more about what this means on the WCRF website.
• Foods preserved by salting increase the risk of stomach cancer.

WCRF Expert Panel opinion – For wholegrains and other foods containing dietary fibre, the evidence shows that, in general, the more people consume, the lower the risk of some cancers.

We are advised to consume at least 30 grams of fibre per day (see the fibre fact sheet from the British Dietetic Association for more information on how to achieve this).

A diet high in all types of plant foods is recommended including at least five portions of vegetables and fruit per day. This poster from WCRF shows what counts as a portion.

b. Animal products

• Red meat and processed meat increase the risk of colorectal cancer.
• Cantonese-style salted fish increases the risk of nasopharyngeal cancer.
• Dairy products decrease the risk of colorectal cancer.

WCRF Expert Panel opinion – For people who eat meat, limit consumption of red meat, such as beef, pork and lamb, to no more than three portions per week: 350–500g cooked weight. Eat little, if any, processed meat.

c. Alcoholic drinks

• Consuming alcoholic drinks increases the risk of:
  • Mouth, pharynx and larynx cancers
  • Oesophageal cancers
  • Breast cancer (pre- and post-menopause)
• Two or more alcoholic drinks a day increase the risk of colorectal cancer.
• Three or more alcoholic drinks a day increase the risk of stomach cancer and liver cancer.
• Up to two alcoholic drinks a day decrease the risk of kidney cancer (though note, WCRF advise that this is far outweighed by the increased risk for other cancers).

WCRF Expert Panel Opinion – The evidence shows that, in general, the more alcoholic drinks people consume, the higher the risk of many cancers.

WCRF advise that for cancer prevention, it’s best not to drink any alcohol at all. Indeed, there is no threshold for the level of consumption below which there is no increase in the risk of at least some cancers.

3. Physical activity

• Being physically active decreases the risk of:
  • Colon cancer
  • Breast cancer (post-menopause)
  • Endometrial cancer
• Vigorous physical activity (e.g. running or fast cycling) decreases the risk of:
  • Pre- and post-menopausal breast cancer

WCRF Expert Panel Opinion – The evidence implies that, in general, the more physically active people are, the lower the risk of some cancers.

We are advised to do at least 150 minutes of moderate intensity activity (examples include brisk walking, cycling, household chores, swimming, dancing) or 75 minutes of vigorous activity (examples include running, aerobics, squash, netball, fast cycling) per week.

4. Other factors related to cancer

The report also covers links between cancer and other dietary factors (including glycaemic load, vitamin supplements and non-alcoholic drinks); height and birth weight; and lactation. For more information, see the summary report.

The 10 cancer prevention recommendations

The report includes 10 key recommendations for cancer prevention. Shown here as an overview infographic, there’s lots more useful detail in the report itself.

For lifestyle factors as discussed within this report, incorporating the recommendations into our lives as a whole package, rather than just focusing on a few individually, will be the most conducive for cancer prevention. It is interesting to know that between 30-50% of all cancer cases are estimated to be preventable through healthy lifestyles and avoiding exposures to occupational carcinogens (substances capable of causing cancer), environmental pollution and certain long-term infections.

NEW resources to help with cancer prevention:

• Cancer Health Check – A new online questionnaire check has been launched to help individuals find out where they are doing well and where they could make changes to their lifestyle to help reduce the risk of cancer.
• Toolkit – WCRF have published a downloadable toolkit which shows key points from the report using lots of visual representations of the findings.
• Interactive Cancer Risk Matrix – This tool gives information on how different aspects of diet, as well as body weight and physical activity, might be linked to cancer risk based on the strength of the evidence.
• Individual sections of the report – these can be accessed digitally as PDFs or as toolkits. This allows us to zoom in on specific dietary factors or different cancers and find out the evidence from the main report.