For colorectum cancer the effect of diet is more immediate, as shown by the change of incidence on migration within 10 to 15 years. Animal studies support an effect of dietary fat for both these sites, in the colon, fat breakdown products appear to have a direct effect on mucosal proliferation, for breast cancer the mechanism is uncertain. For prostate cancer the associations with high fat intake have been more consistent when analyses have been restricted to patients with advanced cancer, supporting an effect on the disease at the later stages of carcinogenesis. Dietary cholesterol intake has been associated with pancreas, lung and bladder cancer. High nitrite and salt consumption are associated with stomach cancer, and high aflatoxin consumption with liver cancer.
Iodine deficiency increases the risk of thyroid cancer.
Protein as such does not seem to be associated with risk of any cancer. Micronutrient deficiency has been particularly associated with oesophagus cancer. Obesity increases the risk of endometrial cancer, ovary cancer and of breast cancer in postmenopausal women, and perhaps also gallbladder and kidney cancer. For endometrial cancer the mechanism is clearly the production of oestrogens by adipose tissue, this mechanism may also operate for breast and ovary cancer. Breast cancer is more frequent in tall than short women, suggesting a role of nutrition in early life.