The relationship between the gut microbiome and human health is widely accepted in the medical community.

Now, new research shows that the breast gland also has a microbiome, and like the gut microbiome, it too can be affected by diet, according to scientists at Wake Forest School of Medicine.

"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 the study's lead author, Katherine Cook, Ph.D., assistant professor of surgery - hypertension and cancer biology at the Medical School, a part of Wake Forest Baptist Medical Center.

Published in the current issue of the journal Cell Reports, the study utilized a well-established non-human primate model of women's health to compare the effects of a Western diet to a Mediterranean diet 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 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 tumour 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."

Previously published research showed 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, Cook said.

Additional pre-clinical studies are being conducted by Medical School researchers to investigate whether oral interventions, such as fish oil or probiotic supplements, can affect microbiome populations in mammary glands and in breast tumours.

The team also is studying the role of bacterial-modified bioactive compounds and bile acids on breast cancer tumour growth, therapeutic responsiveness and inflammation.

Source: Wake Forest Baptist Medical Center