Diet and cancer

Dietary factors are recognized as having a significant effect on the risk of cancers, with different dietary elements both increasing and reducing risk. Diet and obesity may be related to up to 30–35% of cancer deaths,^[1] while physical inactivity appears to be related to 7% risk of cancer occurrence.^[2]

While many dietary recommendations have been proposed to reduce the risk of cancer, few have significant supporting scientific evidence.^[3][4][5] Obesity and drinking alcohol have been correlated with the incidence and progression of some cancers.^[3] Lowering the consumption of sweetened beverages is recommended as a measure to address obesity.^[6]

Some specific foods are linked to specific cancers. There is strong evidence that processed meat and red meat intake increases risk of colorectal cancer.^{[7][8][9][10]} Aflatoxin B₁, a frequent food contaminant, increases risk of liver cancer,^[11] while drinking coffee is associated with a reduced risk.^[12] Betel nut chewing causes oral cancer.^[11] Stomach cancer is more common in Japan due to its high-salt diet.^[11][13] Immigrant communities tend to develop the risk of their new country, often within one generation, suggesting a substantial link between diet and cancer.^[14]

Dietary recommendations for cancer prevention typically include weight management and eating a healthy diet, consisting mainly of "vegetables, fruit, whole grains and fish, and a reduced intake of red meat, animal fat, and refined sugar."^[3] A healthy dietary pattern may lower cancer risk by 10–20%.^[15] There is no clinical evidence that diets or specific foods can cure cancer.^[16]