A Canadian research, published in The Prostate journal, found that men who drank four 200 ml glasses of milk had double the risk of the disease, reports dailymail.co.uk.
Milk contains cow hormones, including insulin-like Growth Factor 1 (IGF-1). These encourage growth and may help to feed prostate cancer and perhaps, to a lesser extent, ovarian cancer.
Researchers from University College London have suggested that a few thousand years ago people avoided milk because it led to gastric pain and upset stomachs. This is because Europeans lacked the gene to produce the enzyme lactase, which breaks down the milk sugar lactose.
However, Professor Walter Willett, chairman of nutrition at the Harvard School of Public Health, says there's little evidence to justify such recommendations, claiming such measures are "likely to cause harm to some people".
Willett says that "many studies have shown a relation between high milk intake and risk of fatal or metastatic prostate cancer, explained by the fact that a high intake increases blood levels of the IGF-1 growth-promoting hormone".