Cleveland Clinic study links gut microbiome and aggressive prostate cancer

 Cleveland Clinic researchers have shown that diet-associated molecules in the gut are associated with aggressive prostate cancer, suggesting dietary interventions may help reduce risk. Findings from the study were published in Cancer Epidemiology, Biomarkers & Prevention.

While more research will be necessary, the study’s lead author Nima Sharifi, MD, says findings from the team’s analysis of nearly 700 patients may have clinical implications for diagnosing and preventing lethal prostate cancer.

For the study, researchers analyzed data from patients previously enrolled in the National Cancer Institute’s Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial.

They studied baseline levels of certain dietary nutrients and metabolites (byproducts produced when a substance is broken down in the gut) found in patients’ blood serum prior to prostate cancer diagnosis. They compared serum levels between healthy patients and those who later received a prostate cancer diagnosis and died from the disease.

The researchers found that men with elevated levels of a metabolite called phenylacetylglutamine (PAGln) were approximately two or three times more likely to be diagnosed with lethal prostate cancer. This metabolite is produced when microbes in the gut break down phenylalanine, an amino acid found in many plant- and animal-based protein sources like meat, beans, and soy.

In addition to PAGln, researchers also discovered that elevated levels of two nutrients abundant in animal products, including red meat, egg yolks and high-fat dairy products, called choline and betaine, also were linked with increased risk for aggressive prostate cancer.

While these nutrients and gut metabolites have been studied previously in heart disease and stroke, this is the first time that gut microbiome metabolites have been studied clinically in relation to prostate cancer outcomes.