Women with breast cancer can increase their chances of survival by avoiding high-fat dairy foods, according to a recent breast cancer dairy study by researchers at Kaiser Permanente Medical Center in Oakland, California. About 12% of the women with breast cancer in the study who consumed at least one daily serving of high-fat dairy died over the course of the 12-year study. In comparison, less than 1% of the women who only consumed under half a serving of high-fat dairy daily died from their cancer. The researchers believe that this is due to the high levels of estrogen found in high-fat dairy products.

Avoiding dairy might be a worthwhile strategy, as the American Cancer Society predicts that 40,000 women will die because of their breast cancer in 2014. Over 200,000 women will receive a breast cancer diagnosis next year as well.

Too Much High-Fat Dairy Increases Breast Cancer Death Risk by Half

About 1,900 women were included the study. All of the women had been diagnosed with breast cancer up to four years prior to the beginning of the study, and all hailed from either Utah or California. At the start of the study, all of the women had already undergone cancer treatment and were showing no signs of cancer.

The researchers determined the women’s eating habits by having them fill out questionnaires, asking how frequently they ate foods such as yogurt, cheese, ice cream and milk. The women were also asked to say whether they consumed low-fat or high-fat versions of these foods.

A total of 349 women in the study experienced a recurrence of their breast cancer, and 189 women died as a result. An additional 189 women died due to causes aside from breast cancer.

Overall, the researchers found that eating more than one serving of high-fat dairy per day increased a woman’s risk of dying from breast cancer by 49% in comparison to eating less than one-half serving of high-fat dairy daily. These women were also 64% more likely to die of any cause, including breast cancer and other diseases and conditions. These conclusions held true even when the researchers accounted for age, smoking habits, tumor advancement, and other factors that could have influenced death risk.

Low-Fat and High-Fat Dairy

Women in the study who consumed increased levels of low-fat dairy did not exhibit an increased risk of dying from breast cancer. The researchers believe that the primary culprit behind the increased death risk observed in the study is the saturated fat found in dairy products. Saturated fat found in non-dairy products doesn’t seem to have an effect on breast cancer death risk, at least not according to this study.

The study did not determine whether eating high levels of high-fat dairy products increases a woman’s risk of developing breast cancer to begin with. Future studies will be needed to determine whether high-fat dairy is linked with the initiation of breast cancer development.

In the study, 2% milk was categorized as low-fat dairy. However, 2% milk actually contains a fair amount of saturated fat. If you have breast cancer, it may be best to stick to skim milk.

Breast Cancer Dairy Risks: The Bottom Line

A new study by researchers at Kaiser Permanente Medical Center has found that eating high-fat dairy products may greatly increase the risk of dying for women who have or have had breast cancer.

The full text of the study can be found online in the Journal of the National Cancer Institute.