Men who eat a lot of cheese could be at a higher risk of contracting testicular cancer, Canadian researchers conclude in a new study.
Scientists at the University of Ottawa in Canada set out to investigate the impact of diet on this cancer - the most common cancer in Canadian men aged between 20 and 45 years old. They claim that overall knowledge of the causes of testicular cancer risk in general, and more specifically with diet, is fairly limited.
Data from 601 cases of testicular cancer and 744 population-based controls collected in eight of the 10 Canadian provinces between 1994-97 were used to explore the relationship between diet and testicular cancer risk.
The researchers systematically examined 17 food groups, 15 nutrients and four individual foods based on data collected through a 69-item food-frequency questionnaire.
"Our results suggest that high dairy product intake, in particular high intake of cheese is associated with an elevated risk of testicular cancer in Canadian males," said lead researcher Michael J. Garner.
The authors suggest that the apparent increase in risk may stem from the high amounts of the female sex hormones oestrogen and progesterone in dairy products.
Dairy products have also been linked to an increased risk of prostate cancer, and in women, breast cancer. At the same time, they are thought to reduce chances of developing ovarian and colon cancer.
Michael Garner noted that elevated levels of oestrogen in the womb predispose someone toward the disease, and a factor such as high cheese intake may increase the chance of getting it. The large amounts of fat, calcium and protein in cheese might also be a link to testicular cancer, the paper says.
The study found a less significant association between processed meat and baked goods and the disease. The baked goods finding may not be accurate, partly because of the wide array of foods included in that category, Garner said. Processed meats contain nitrates, which are potential carcinogens, and are high in fat.
The authors did however emphasise that the results do not mean people should stop eating cheese, but should do so in moderation.
The study, published in the October issue of the International Journal of Cancer, is regarded as the most comprehensive look yet at the link between diet and risk of testicular cancer.