Evidence suggest that consistently drinking as little as a quarter of a cup of dairy milk per day was associated with an increased risk of breast cancer of 30 percent.
Drinking one cup per days was associated with a 50 percent increase.
Drinking two to three cups of milk per day increases the risk 70 to 80%.
Current U.S. Dietary guidelines recommend three cups of milk per day. “Evidence from this study suggests that people should view that recommendation with caution,” Fraser said.
Dietary intakes of nearly 53,000 North American women were evaluated for the study, all of whom were initially free of cancer and were followed for nearly eight years. Dietary intakes were estimated from food frequency questionnaires (FFQ), also repeated 24 hour recalls, and a baseline questionnaire had questions about demographics, family history of breast cancer, physical activity, alcohol consumption, hormonal and other medication use, breast cancer screening, and reproductive and gynecological history.
By the end of the study period, there were 1,057 new breast cancer cases during follow-up. No clear associations were found between soy products and breast cancer, independent of dairy. But, when compared to low or no milk consumption, higher intakes of dairy calories and dairy milk were associated with greater risk of breast cancer, independent of soy intake. Fraser noted that the results had minimal variation when comparing intake of full fat versus reduced or nonfat milks; there were no important associations noted with cheese and yogurt.
“However,” he said, “dairy foods, especially milk, were associated with increased risk, and the data predicted a marked reduction in risk associated with substituting soymilk for dairy milk. This raises the possibility that dairy-alternate milks may be an optimal choice.”
Canada’s Food Guide was updated in January for the first time in more than a decade. Noticeably, there was a de-emphasis on dairy consumption and the suggestion Canadians should instead consume more water.