Study: Drinking dairy milk linked to breast cancer in women

Note from Millie–  Dairy foods do not belong in the human body.  Breastfed until 2 years old and after that we do not need dairy.

New U.S. research has found that drinking even a moderate amount of dairy milk appears to be linked to an increased risk of breast cancer in women.

Hot on the heels of a review from top nutrition scientists that cautioned against drinking cow’s milk comes another study with another caution: drinking milk increases the risk of developing breast cancer, say the researchers. But this finding comes from an observational study, and there may be confounders that are not accounted for, says an expert not involved with the study.   

The latest research was based on data from the long-running larger study called Adventist Health Study-2 (AHS-2), which is looking at diet and health among Seventh Day Adventists in North America. Past results from this study have suggested that Seventh Day Adventists have longer life spans and lower rates of some cancers, perhaps because of heathier lifestyles.

The latest analysis suggests that milk raises breast cancer risk, and the more you drink the higher your risk may be. 

“Consuming as little as 1/4 to 1/3 cup of dairy milk per day was associated with an increased risk of breast cancer of 30%,” first author Gary E. Fraser, MBChB, PhD, said in a press statement. Fraser is affiliated with the School of Public Health at Loma Linda University, California.

“By drinking up to 1 cup per day, the associated risk went up to 50%, and for those drinking 2 to 3 cups per day, the risk increased further to 70% to 80%,” he added.

The findings were published February 25 in the International Journal of Epidemiology.

“The AHS study is provocative, but it’s not enough to warrant a change in guidelines. The caution being espoused by the authors is not warranted given the observational nature of this study,” commented Don Dizon, MD, director of Women’s Cancers, Lifespan Cancer Institute at Brown University in Providence, Rhode Island. He was not involved with the study and was approached by Medscape Medical News for comment.

Because of its observational design, the study cannot prove that cow’s milk causes breast cancer, Dizon emphasized.

“I’d want to see if the findings are replicated [by others]. Outside of a randomized trial of [cow’s] milk vs no milk or even soy, and incident breast cancers, there will never be undisputable data,” he said.

“Probably the biggest point [about this study] is not to overinflate the data,” Dizon added.

He noted that the results were significant only for postmenopausal women, and not for premenopausal women. Moreover, analyses showed significant associations only for hormone receptor-positive cancers.