Nutrition and the prevention of cancer.

Many studies have shown an association between nutrition and cancer and, since one in three people in England will develop cancer and one in four will die from the disease, there is great interest in prevention through diet. The issues are complex and evidence is often limited or equivocal. This review considers the strength of the evidence and puts the risks of cancer in context. It concludes that although no dietary changes can be guaranteed to prevent cancer, on balance there is enough evidence to recommend the current official "healthy eating" guidelines as the best advice for reducing the risk of diet-associated cancers. The greatest protection against cancer coincides with eating more fruit, vegetables and wholegrain foods. Overindulgence in alcohol, smoking, obesity and lack of exercise may interact with dietary factors to increase the risk of some cancers. Healthy lifestyle measures such as regular exercise, avoiding overweight, not smoking and limiting the intake of alcohol can therefore also be recommended as helping to reduce the risk of cancer. When advising individuals, it is necessary to consider all aspects of the person's lifestyle and to bear in mind that there are some limitations to the current evidence. A summary of the practical recommendations for reducing cancer risk is included.