Men who consume more dairy per day could have up to a 25% higher risk of prostate cancer, especially if it is cow’s milk. This has been warned by a study by the Loma Limna University Health School of Medicine (USA) after analyzing the link between dairy products, calcium and cases of this type of cancer.
The research, published in The American Journal of Clinical Nutrition, took into account dairy consumption data from 28,737 healthy North American men who were followed for a period of eight years. After that time, 1,254 cases of prostate cancer were reported among the participants.
The results after the analysis indicated that men who ate about 430 grams of dairy a day – equivalent to a cup and ¾ of milk – had a 25% higher risk of prostate cancer compared to those who only ate 20.2 grams of daily dairy –half a glass of milk–, a figure that increased even more when compared to those who did not take this type of food.
The type of cow’s milk does not influence the risk of prostate cancer
This association between dairy and prostate cancer was not related to its calcium content, since nuts, seeds and other vegetables and fruits rich in calcium did not increase the risk. Therefore, this mineral would not be the cause of the increased risk. In addition, the results varied very little when whole milk intake was compared to reduced or skimmed milk, yogurts and cheeses did not have any significant association.
Increased risk of prostate cancer from dairy consumption could be due to the presence of sex hormones in cows’ milk
As dairy consumption increased, the odds of developing prostate cancer increased steadily. Increasing intake by 50 grams did not cause the same increased risk as when servings were higher. “Most of the continued increase in risk disappears by the time you get to 150 grams, about two-thirds of a cup of milk per day. It’s almost as if some biological or biochemical pathway is saturated in about two-thirds of a cup of milk per day,” says Gary Fraser, lead researcher on the study.
The possible explanation that researchers are considering for this association is the presence of sex hormones in cow’s milk. And it is that, up to 75% of lactating dairy cows are pregnant when their milk is extracted, which adds to the fact that prostate cancer is more likely to respond to hormones.
Previous studies have linked dairy products and other animal proteins to higher blood levels of a hormone, insulin-like growth factor-1 (IGF-1), which evidence suggests promotes certain types of cancer, including the prostate.
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