Nutrition and cancer: the current epidemiological evidence.

We have examined the current scientific evidence on the relationship between nutrition and the most frequent tumours in the Spanish population: lung, colorectal, prostate, breast and stomach. Consumption of fruit is negatively associated with cancer of the lung and stomach, possibly with colorectal cancer, but probably not with prostate cancer and breast cancer. Consumption of vegetables probably reduces the risk of colorectal and stomach cancer, but probably is not associated with cancer of the lung, prostate and breast. Consumption of red and processed meat is positively associated with colorectal cancer and probably with stomach cancer. Animal fat is possibly associated with colorectal cancer and probably with prostate and breast cancer. High alcohol intake increases the risk of colorectal and breast cancer, while dairy products and calcium seem to decrease the risk of colorectal cancer. Obesity is a recognised risk factor of colorectal cancer and breast cancer in postmenopausal women, while foods with a high glycaemic index and glycaemic load possibly increase the risk of colorectal and prostate cancer. The relevance of nutrition on the cancer process is evident. Nevertheless important issues remain to be solved and further studies are needed. This accumulative knowledge should be used by public health authorities to develop recommendations and activities to reduce overweight and obesity and to promote healthy dietary habits.