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Diet, nutrition, and cancer risk: what do we know and what is the way forward?

BMJ 2020; 368 doi: (Published 05 March 2020) Cite this as: BMJ 2020;368:m511

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  1. Timothy J Key, deputy director1,
  2. Kathryn E Bradbury, senior research fellow2,
  3. Aurora Perez-Cornago, senior nutritional epidemiologist1,
  4. Rashmi Sinha, senior investigator3,
  5. Konstantinos K Tsilidis, assistant professor of epidemiology45,
  6. Shoichiro Tsugane, director6
  1. 1Cancer Epidemiology Unit, Nuffield Department of Population Health, University of Oxford, Oxford, UK
  2. 2National Institute for Health Innovation, School of Population Health, University of Auckland, Auckland, New Zealand
  3. 3Metabolic Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
  4. 4Department of Hygiene and Epidemiology, University of Ioannina School of Medicine, Ioannina, Greece
  5. 5Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
  6. 6Center for Public Health Sciences, National Cancer Center, Tokyo, Japan
  1. Correspondence to: TJ Key tim.key{at}

Timothy J Key and colleagues describe the evidence linking diet and nutrition to cancer risk, concluding that obesity and alcohol are the most important factors

Scientists have suspected for decades that nutrition has an important influence on the risk of developing cancer. Epidemiological studies as early as the 1960s showed that cancer rates varied widely between populations and that cancer rates in migrants moving from low to high risk countries could rise to equal or sometimes exceed the rates in the host population.12 These observations implied the existence of important environmental causes of cancer, and other studies showed strong correlations between many types of cancer and dietary factors; for example, countries with high intakes of meat had high rates of colorectal cancer.3 Furthermore, experiments in animals showed that cancer rates could be altered by manipulating diet, with compelling evidence that restricting energy intake causes a general reduction in cancer development.45

Cancer is predicted to be the leading cause of death in every country of the world by the end of this century.6 Although dietary factors are thought to be important in determining the risk of developing cancer, establishing the exact effects of diet on cancer risk has proved challenging. Here we describe the relatively few dietary factors that clearly influence risk of cancers along the digestive tract (from top to bottom) and of other common types of cancer,78 as well as challenges for future research.

Cancers of the oral cavity and pharynx

Nasopharyngeal cancer is common in a few populations around the globe, such as the Cantonese population in southern China and some indigenous populations of South East Asia, the Arctic, north Africa, and the Middle East.9 Consumption of foods preserved with salt has been linked with this cancer, and the mechanism might be through nitrosamine formation or …

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