In studies recently conducted at the Beckman Research Institute at the City of Hope, Duarte, CA and published in the October 2011 issue of The Journal of Nutrition, researchers found that feeding blueberry powder to mice significantly reduced the growth and spread of triple negative breast cancer, a very aggressive form of cancer. Triple negative breast cancer accounts for 10 to 15% of all breast cancer cases and is highly resistant to traditional chemotherapy treatments. The term “triple negative” refers to the tumors testing negative for estrogen, progesterone and HER-2 receptors, all of which allow for more treatment options.

For the study, researchers led by Drs. Lynn Adams and Shiuan Chen fed groups of mice specially formulated diets containing 5% freeze-dried blueberry powder, 10% blueberry powder or a control diet containing no blueberry powder. All three diets had a similar nutrient composition and the animals ate and drank about the same amount regardless of group. The human equivalent of the 5% diet is about 2 cups of fresh highbush blueberries per day.

The results?  On average, tumors were 75% smaller in the 5% blueberry experimental group and 60% smaller in the 10% group as compared to the control group. The difference between the two blueberry groups was not significant. Further confirmation of the results was obtained when the researchers conducted molecular studies on tumor tissue and found significant differences between the blueberry-fed and control groups in gene patterns known to be related to inflammatory diseases and the proliferation and spread of cancer cells.

A second study that examined the effect of consuming blueberries on the spread of breast cancer (metastasis) indicated that mice fed a diet containing 5% blueberry powder developed 70% fewer liver cancer tumors and 25% fewer lymph node tumors when compared to the control mice.