The relationship between the gut microbiome and human health is widely accepted in the medical community. New research, published today in Cell Reports, shows that the breast gland also has a microbiome, and like the gut microbiome, it too can be affected by diet.
"Being able to shift the breast microbiome through diet may offer a new approach to preventing breast cancer or at least reducing the risk," said senior author Katherine Cook, Ph.D., of Wake Forest Baptist Medical Center.
The study utilized a well-established non-human primate model of women's health to compare the effects of two diets on breast tissue. Female monkeys were fed a specially prepared diet that mimicked either a high-fat Western diet or a plant-based Mediterranean diet for two-and-a-half years, which is equivalent to about eight human years.
The research team found that the group that ate the Mediterranean diet had a distinctly different set of bacteria in their breast tissue than those that ate the Western diet. Consuming the Mediterranean diet led to about a 10-fold increase of mammary gland Lactobacillus, a bacteria shown to decrease breast cancer tumor growth in preclinical models. The Mediterranean diet also resulted in more bile acid metabolites in the breast tissue, which may reduce breast cancer risk.
"We were surprised that diet directly influenced microbiome outside of the intestinal tract in sites such as the mammary gland," Cook said. "However, we are just at the early stages of understanding how dietary effects on the microbiome might be used to protect women from breast cancer."
Additional pre-clinical studies are being conducted by researchers at the medical school to investigate whether oral interventions, such as fish oil or probiotic supplements, can affect microbiome populations in mammary glands and in breast tumors. The team is also studying the role of bacterial-modified bioactive compounds and bile acids on breast cancer tumor growth, therapeutic responsiveness, and inflammation.
Previously published research showed that microbiome populations can vary due to geographic area. Therefore, to strengthen future studies, the team plans to obtain tissue biopsies from animals housed in different regions of the country.