Carefully chosen nutritional changes may slow prostate cancer’s progression without immediate medical intervention, according to a new study.

Researchers at the University of California–Los Angeles (UCLA) have discovered that a diet low in omega-6 fatty acids and rich in omega-3s, combined with fish oil supplements, could potentially reduce cancer cell growth in patients tracking the cancer instead of treating it, an approach called active surveillance.

“This is an important step toward understanding how diet can potentially influence prostate cancer outcomes,” Dr. William Aronson, professor of urology at the David Geffen School of Medicine at UCLA and study first author, said in a statement.

Tracking Cancer Cell Multiplication

The double-blinded study, published in the Journal of Clinical Oncology, involved 100 men living with low-risk or favorable intermediate-risk prostate cancer, which falls between low-risk and high-risk categories, who opted for active surveillance instead of immediate treatment. This means they chose to closely monitor the cancer rather than immediately undergo treatment like surgery or radiation therapy.

Prostate cancer is the most common cancer among men in the United States and is currently the second leading cause of cancer-related deaths in this demographic. While age is the most prevalent risk factor, other contributing factors include being African American and having a family history of the disease.

Participants were randomly assigned to continue their regular diet or follow a low omega-6 and high omega-3 diet, supplemented with fish oil, for one year.

Researchers then tracked changes to levels of a biomarker called the Ki-67 index, which indicates how fast cancer cells multiply and is a key predictor of cancer progression, spread (metastasis), and overall survival.

High Omega-3, Low Omega-6 Group Had Slower Cancer Growth

The findings revealed that the group adhering to the low omega-6, high omega-3 diet supplemented with fish oil had a 15 percent decrease in the Ki-67 index. In contrast, the control group exhibited a 24 percent increase in their Ki-67 index score.

Researchers did not observe differences in other cancer growth markers often used to monitor prostate cancer progression, such as Gleason grade, which measures how much the cancer cells in a biopsy sample differ from normal prostate cells.

“This significant difference suggests that the dietary changes may help slow cancer growth, potentially delaying or even preventing the need for more aggressive treatments,” Aronson stated in the press release.

Oils rich in omega-3 fatty acids include fish, krill, cod liver, and algal oils. Algal oil is a vegetarian-friendly option derived from algae. Foods rich in omega-3 include fatty fish, walnuts, and green leafy vegetables. On the other hand, sources of omega-6 fatty acids include sunflower, safflower, soy, sesame, and corn oils.

However, the researchers caution that further research is necessary to confirm the long-term benefits of omega-3 fatty acids and lower omega-6 intake in managing prostate cancer.

“Many men are interested in lifestyle changes, including diet, to help manage their cancer and prevent the progression of their disease,” Aronson said. “Our findings suggest that something as simple as adjusting your diet could potentially slow cancer growth and extend the time before more aggressive interventions are needed.”