Most people know that smoking and sunburn increase risk of cancer, but there is not the same level of awareness about how risk is affected by our diets and our activity levels.
It can often feel like we are always reading about the latest food that might either reduce or increase our cancer risk. In fact, this happens so often that many people respond by just ignoring all the advice.
This is why at WCRF, we conducted the biggest ever review of the evidence and then distilled all the scientific research on the subject into 10 recommendations that people can incorporate into their daily lives.
Following these recommendations is not a guarantee against developing cancer, but they do represent the best advice available anywhere on how we can reduce our risk. Also, they are not a question of all or nothing. Making even small long-term changes in the right direction can make a difference.
Be as lean as possible without becoming underweight
Maintaining a healthy weight is one of the most important things you can do to reduce your risk of cancer. We advise people to aim to be towards the lower end of the healthy Body Mass Index (BMI) range, which is a BMI from 18.5 to 25.
There is now convincing evidence that excess body fat is a risk factor for six types of cancer, including breast cancer and bowel cancer. In fact, scientists now say that, after not smoking, maintaining a healthy weight is the most important thing you can do for cancer prevention.
Be physically active for at least 30 minutes every day.
Most of us know that regular physical activity can help keep our hearts healthy – and the good news is that it can also reduce our risk of cancer.
This is why we recommend people aim to be physically active for at least half an hour a day and then, as fitness improves, increase this level to about an hour.
And there is a double effect of physical activity. Not only does it reduce cancer risk in its own right, but being regularly active is also a great way of maintaining a healthy weight.
Limit consumption of energy-dense foods (foods high in fats and/or added sugars and/or low in fibre) and avoid sugary drinks.
Choosing foods and drinks without too many calories in them can help us avoid being overweight and so they can indirectly reduce our risk of cancer.
This is why it is a good idea to read food labels, as many of the foods we eat regularly are higher in calories than we might expect.
Eat more of a variety of vegetables, fruits, wholegrains, and pulses such as beans.
At WCRF we recommend a plant-based diet, including at least five portions of a range of fruits and vegetables every day.
The evidence shows that eating fruits and vegetables probably reduces cancer risk.
And fruits and vegetables, like physical activity, have a double effect for cancer prevention. As well as the direct effect they have on cancer risk, people who eat plenty of them are also less likely to be overweight.
Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats.
For cancer prevention, WCRF recommends limiting consumption of red meat (such as beef, pork and lamb) to 500g per week (cooked weight). To help visualise how much this is, a medium portion of roast beef or pork is about 90g and a medium steak is about 145g.
People are also advised to avoid processed meats such as ham, bacon and some sausages.
This is because there is convincing evidence that red and processed meat increase risk of bowel cancer, which is one of the most common types of cancer in the UK.
If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day.
The evidence that all types of alcoholic drinks are a cause of a number of cancers is now stronger than ever before.
This means cutting down on the amount you drink could play an important role in reducing your cancer risk.
Limit consumption of salty foods and foods processed with salt (sodium).
Many of us know that having too much salt increases risk of high blood pressure.
But people might not be aware that consuming too much salt also probably increases risk of stomach cancer.
Don’t use supplements to protect against cancer.
We do not recommend taking supplements for cancer prevention and instead suggest people aim to get the nutrients they need from their diet.
This is because the effect of vitamin supplements is often unpredictable and in some cases can actually increase cancer risk.
It is best for mothers to breastfeed exclusively for up to 6 months and then add other liquids and foods.
Research is increasingly showing that it is what we do throughout the whole of our lives that affects our cancer risk and this is why we say it is never too early to think about cancer prevention.
Breastfeeding is a good example of this, as it probably reduces the risk of the baby being overweight as a child.
But there is also a cancer prevention benefit for the mother, as breastfeeding your baby reduces risk of breast cancer.
After treatment, cancer survivors should follow the recommendations for cancer prevention.
There is some evidence that, particularly with breast cancer, cancer survivors can reduce their risk of it recurring by eating healthily and maintaining a healthy weight.
This is an area where more research is needed and this is why cancer survivorship is one of the priority areas for WCRF’s own research programme.
But while this research is being carried out, people who want to stop cancer recurring are best advised to follow the recommendations for preventing it in the first place.
World Cancer Research Fund (WCRF) raises awareness that cancer is largely preventable and helps people make choices to reduce their chances of developing the disease.
This includes research into how cancer risk is related to diet, physical activity, and weight management, and education programmes that highlight the fact that about a third of cancers could be prevented through changes to lifestyle. For more information on the charity’s work, visit www.wcrf-uk.org
The WCRF report, called Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective, was launched in November 2007 and is the most comprehensive report ever published on the link between cancer and lifestyle. For more information, visit www.dietandcancerreport.org