High-Fat Dairy May Increase Risk for Breast Cancer Death
Nick Mulcahy
Mar 15, 2013
Full Story: http://www.medscape.com/viewarticle/780893
The type of dairy product that women with breast cancer consume could be an important lifestyle choice.
In a new observational study, high-fat dairy intake was linked to breast-cancer-specific outcome. Specifically, consuming at least half a serving of high-fat dairy per day increased the risk of dying from the disease. Consuming low-fat dairy, however, was unrelated to recurrence or survival.
This is the first-ever study to assess the association between low- and high-fat dairy and breast cancer, according to the authors, led by Candyce Kroenke, ScD, MPH, from Kaiser Permanente in Oakland, California. The results were published online March 14 in the Journal of the National Cancer Institute.
The authors conducted this study to determine whether dietary fat in dairy, which is a source of estrogenic hormones, might be related to worse breast cancer survival.
Women with breast cancer who are concerned about high-fat dairy have dietary alternatives, they note.
“Consuming plant-based milks or nonfat dairy products may a reasonable approach for limiting risk of adverse outcomes,” they write. In other words, breast cancer patients and survivors should consume rice, soy, or nonfat milk, cheese, yogurt, ice cream, butter, and other products.
Dr. Kroenke summed up the study in an email to Medscape Medical News: “In short, this study suggests that to improve survival, breast cancer survivors might shift away from high-fat to lower-fat dairy options, reduce high-fat dairy intake, and shift toward plant-based foods and milks (with little added sugar and salt).”
The study is observational and therefore is not definitive. But dairy products have been positively associated with other hormonal cancers, such as those of the prostate, endometrium, and ovaries, the authors point out.
Study Details
All 1893 women in the study, who came from the Life After Cancer Epidemiology study, were diagnosed with early-stage invasive breast cancer from 1997 to 2000. They completed the Fred Hutchinson Cancer Research Center Food Frequency Questionnaire after diagnosis. During a median follow-up of 11.8 years, 349 women had a recurrence and 372 died — 189 from breast cancer.
The authors evaluated the association between subsequent outcomes and categories of cumulative average dairy fat intake at baseline and at 5- to 6-year follow-up.
In multivariable-adjusted analyses, overall dairy intake was unrelated to breast-cancer-specific outcome, although it was positively related to overall mortality. In other words, with regard to breast cancer mortality, eating dairy is not a problem in and of itself, it is the type of dairy that matters.
High-fat dairy intake was positively associated with outcome. Breast cancer mortality was higher in women who consumed half to 1 serving of high-fat dairy per day than in those who consumed less than half a serving (hazard ratio [HR], 1.20); it was also higher in women who consumed more than 1 serving per day (HR, 1.49; Ptrend = .05). All-cause mortality (P trend < .001) and mortality not related to breast cancer (P trend = .007) were also higher.
The relation between high-fat dairy intake and breast cancer recurrence was positive but not statistically significant.
Ice cream was no worse than milk; the higher risk was consistent across different types of high-fat dairy products, the authors report.
The study was funded by the National Cancer Institute. The authors have disclosed no relevant financial relationships.
J Natl Cancer Inst. Published online March 14, 2013. Abstract