The size of breast tumors on lab mice was between 60 and 75% smaller when the animals were fed blueberry powder along with their diet, according to findings published in The Journal of Nutrition.
“Importantly, the dosage used in these studies was nontoxic and may be considered physiologic, because the human equivalent dose of the 5% BB diet (based on body surface area) is 300 g (10.6 oz.) of fresh blueberries (about 2 cups per day),” wrote researchers from the Division of Tumor Cell Biology at the Beckman Research Institute of the City of Hope in California.
“Future clinical trials using whole blueberry powder are planned that will aid in the determination of a suitable human dose. It is our hope that the knowledge gained from this study may aid in the design of future dietary strategies for the prevention of [triple negative breast cancer].”
Consumer interest in blueberries and the compounds they contain has increased in recent years, following results from studies reporting a wide range of health benefits, most notably for brain health and reducing the risk of Alzheimer’s.
The beneficial effects of the blueberries are thought to be linked to their flavonoid content - in particular anthocyanins and flavanols.
The new study adds to the potential health benefits of the berry by indicating a potential for reducing the growth of breast tumors.
The California-based researchers performed two separate experiments. The first put mice in one of three diet groups: A control diet or the diet supplemented with 5% or 10% blueberry powder.
After two weeks of feeding the mice received injections containing aggressive breast cancer cells. After a further six weeks of observation the researchers reported that the 5 and 10% blueberry groups displayed a 75 and 60% reduction in tumor size, compared to the control group.
In addition, results from molecular analysis revealed that blueberry consumption was associated with an alteration in the expression of genes related to inflammation, cancer, and metastasis in such a way that cancer risk would most likely decline, they said.
The second study divided lab animals into two diet groups: A control diet and the diet supplemented with 5% blueberry powder.
Results from this study showed that significant decreases in cancer spread and growth (metastasis) in animals consuming the blueberry powder.
“Interestingly, tumor volume was lower in the 5% blueberry diet than the 10% blueberry diet, although this difference was not significant (no dose response observed),” wrote the researchers.
“This suggests that there may be an optimal level of blueberry intake.”
Source: Journal of Nutrition
Volume 141, Pages 1805-1812
“Whole blueberry powder modulates the growth and metastasis of MDA-MB-231 triple negative breast tumors in nude mice”
Authors: L.S. Adams, N. Kanaya, S. Phung, Z. Liu, S. Chen