WINSTON-SALEM, NC – Although people typically take supplements for their gut health, a new study shows that a popular supplement can be very beneficial for breast health as well. Researchers at the Wake Forest School of Medicine say fish oil supplements appear to alter the breast microbiome and reduce cancer risk.
Many dieters and people who take probiotics are likely familiar with the gut microbiome. This accumulation of billions of microorganisms that live in the gut plays an important role in maintaining balance and the health of everyone. However, study authors say that there is also a breast microbiome that regulates breast tissue health and determines the risk of tumor development.
In 2018, scientists at Wake Forest Baptist Health discovered that a person’s diet can affect this microbiome, just like those in the gut. Now the study authors have focused on fish oil as a particularly healthy substance that can alter breast cancer tumors.
Any exposure to a high-fat diet can increase the risk of cancer
To study the effects of diet on breast cancer risk, the researchers conducted three separate experiments with human and animal cancer patients. Specifically, the scientists examined the connection between the development of cancer and the consumption of a high-fat diet.
“Obesity, which is typically associated with a high-fat diet, is a known risk factor for postmenopausal breast cancer,” said Katherine L. Cook, Ph.D., assistant professor in the departments of Surgery-Hypertension and Cancer Biology in a news release. “But there is still much we don’t know about the relationship between obesity and microbiomes and the implications for breast cancer and patient outcomes.”
In the first study, the researchers fed mice susceptible to breast cancer either a high-fat or a low-fat diet. The results showed that mice on the high-fat diet developed more tumors, which were also larger and grew faster.
In the next experiment, the team performed a series of stool transplants between these two groups of mice. The study authors transplanted the microbiome of mice on a high-fat diet into the low-fat group and vice versa. To their surprise, the researchers discovered that low-fat mice that were transplanted from high-fat mice developed as many cancerous breast tumors as those who actually ate fatty foods.
“Simply replacing the low-fat diet gut microbiome with the high-fat diet animal microbiome was enough to increase the risk of breast cancer in our models,” adds Cook. “These results underscore the relationship between the microbiome and breast health.”
How does fish oil help prevent this?
The final phase of the study included human breast cancer patients in a double-blind, placebo-controlled clinical study. Patients consumed either a placebo or fish oil supplements for two to four weeks before undergoing a lumpectomy or mastectomy.
The results show that adding fish oil to a patient’s diet changes the microbiome in both non-cancerous and malignant breast tissue. Researchers discovered that those who took the supplements for four weeks had more lactobacillus in normal tissues around a tumor.
Lactobacillus is a type of bacteria that scientists say can reduce breast cancer tumor growth. The team also found fewer Bacteroidales and Ruminococcus microbes in the group’s breast tumors. However, the meaning of this change is still unclear.
“This study provides additional evidence that diet plays a critical role in shaping the gut and breast microbiome,” concludes Cook. “Ultimately, our study underscores that potential nutritional interventions could lower the risk of breast cancer.”
Cook’s team is now investigating whether probiotics have a similar impact on breast health and the risk of tumor development.
The study appears in the journal Cancer Research.