Two new American scientific studies examine the association of diet with two types of cancer and present their results.
High consumption of fish is associated with an increased risk of skin cancer (melanoma), while many dairy products, especially milk, have an increased risk of prostate cancer, according to two new American scientific studies.
THE first research by researchers at Brown University in Rhode Island, which included 491,367 adults with an average age of 62 over a period of 15 years, was published in the journal Cancer Causes & Control. Of these, 5,034 (approximately 1%) were diagnosed with malignant melanoma and 3,284 (0.7%) with local stage 0 melanoma.
The study found that the risk of malignant melanoma is 22% higher for those whose average daily intake of fish is about 43 grams, while increased by 28% is the risk of developing cancer cells only in the outer layer of the skin (stage 0 melanoma), compared to with those who eat only 3.2 grams of fish a day on average.
Those who consumed an average of 14.2 grams of tuna per day had a 20% higher risk of malignant melanoma and 17% of stage 0 melanoma, compared with those who had an average daily tuna consumption of only 0.3 grams. Also, those who had an average daily intake of 17.8 grams of non-fried fish had an 18% higher risk of malignant melanoma and 25% of stage 0 melanoma, compared with those who ate only 0.3 grams of non-fried fish a day. On the other hand, no significant association was found between fried fish and melanoma.
Given that fish consumption is on the rise in Europe and the US, as well as the incidence of skin cancer, the researchers stressed the need to further investigate the relationship between fish consumption and melanoma, the most aggressive form of skin cancer. The researchers hypothesized that their findings could be attributed to chemicals that have reached the body of the fish (polychlorinated biphenyls, dioxins, arsenic, mercury, etc.), which are then passed on to humans who eat these fish, increasing – among others – the risk of skin cancer. However, they consider it premature to recommend changes in fish consumption and ask for the issue to be further studied.
THE second study from the School of Medicine and Public Health of the Christian University of Loma Linda in California, led by Professor Gary Fraser, published in the American Journal of Clinical Nutrition, analyzed data from more than 28,000 men without at the beginning of the research that lasted about eight years, during which 1,254 people were diagnosed with prostate cancer.
It was found that those who consumed 430 grams of dairy per day, had a 25% increased risk for this cancer compared to those who consumed only 20 grams of dairy per day. Researchers advise men at high risk for prostate cancer (eg due to a family history) to limit their intake of dairy products, especially milk.
The increased risk is not related to calcium coming from a source other than dairy, so other substances in dairy play a role in prostate cancer, according to the researchers. Also, the consumption of cheese and yogurt did not seem to significantly increase the risk, which mainly concerns milk, which contains increased animal hormones.
