This common fatty acid may slow the progression of prostate cancer

Omega-3s might hinder the growth of prostate tumors through the gut microbiota. That's what a study published in Nature Communications by a research team from Université Laval, McGill University, and the Uniformed Services University of the Health Sciences suggests.


The researchers reached this conclusion after examining the link between the gut microbiota and the aggressiveness of prostate tumors from multiple perspectives. Initially, they analyzed the gut microbiota of 62 men diagnosed with prostate cancer who were awaiting prostate resection.

After surgery, the researchers divided the patients into three groups based on their tumor volume. Their finding: patients with tumors in the upper third of the volume range had a gut microbiota that was 8% less diverse than those with tumors in the lower third.

Next, the researchers analyzed the gut microbiota of 47 men who had undergone prostate resection five years earlier. Patients showing signs of cancer recurrence had a more altered gut microbiota.

“On one hand, the biodiversity of their microbiota was 18% lower than that of patients without recurrence. On the other hand, certain bacterial groups were overrepresented compared to what was observed in patients without cancer recurrence,” notes the study leader, Vincent Fradet, a professor at the Faculty of Medicine at Université Laval and a researcher at the Institute of Nutrition and Functional Foods and the CHU de Québec-Université Laval Research Center.

The researchers then transplanted the gut microbiota from patients with aggressive prostate cancer to model mice used to study this cancer. "We found that this fecal transplantation stimulated the growth of prostate tumors in the mice, suggesting some form of communication between the gut microbiota and prostate cancer," Professor Fradet explains.

Finally, the researchers recruited 41 men who had undergone a biopsy for prostate cancer and were awaiting prostate resection. They asked 21 of them to take omega-3 supplements until the time of surgery, which occurred on average 7 weeks later, while the others took a placebo.

The grade of their tumor, which measures the aggressiveness of the cancer, was assessed at the time of the biopsy and resection, notes Professor Fradet. "There was a reduction in tumor grade in 19% of subjects in the omega-3 group compared to 5% in the control group. Additionally, we saw an increase in tumor grade in 10% of subjects in the omega-3 group versus 30% in the control group."

The researchers found that taking omega-3s resulted in a decrease in the abundance of a family of bacteria called Ruminococcaceae in the patients' stools. This decrease was associated with a lower risk of an increase in tumor grade. Previous studies have shown that these bacteria increase the risk of rapid prostate cancer growth. They also increase the risk of resistance to hormone treatments because they convert androgen precursors into androgens, hormones that stimulate prostate cancer.

"Most prostate cancers progress slowly," Vincent Fradet reminds. "Since prostate resection and radiotherapy have negative impacts on patients' quality of life, it would be beneficial to have interventions that delay the need for these treatments. Our results suggest that consuming omega-3s could be a simple and non-invasive way to slow the progression of prostate cancer. However, the clinical demonstration of this hypothesis remains to be done," he cautiously concludes.