3 dietary molecules linked to aggressive prostate cancer

Prostate cancer is most common in older men, with about 6 in 10 cases occurring in men aged 65 and older. However, there has been a nearly sixfold increase in prostate cancer diagnoses in men aged 55 and younger in the last two decades. More than 10 percent of U.S. diagnoses now occur in these younger men, and their prostate cancer is more likely to be aggressive.

Given the sobering survival prognosis of three years for advanced prostate cancer, investigators are searching for ways to help reduce the risk of developing an aggressive form of the disease. In a recent study, researchers examined whether there is a connection between the gut microbiome and aggressive prostate cancer. This is what they found…

Aggressive prostate cancer could be linked to gut health

For the first time, researchers have demonstrated that certain dietary changes in the gut microbiome are linked with an aggressive form of prostate cancer. This suggests that diet-based interventions may help reduce risk of this deadly prostate cancer.

“We found that men with higher levels of certain diet-related molecules are more likely to develop aggressive prostate cancer,” says lead author Dr. Nima Sharifi, director of Cleveland Clinic’s Genitourinary Malignancies Research Center. “As we continue our research in this area, our hope is that one day these molecules can be used as early biomarkers of prostate cancer and help identify patients who can modify their disease risk by making dietary and lifestyle changes.”

The study analyzed data from patients already enrolled in the National Cancer Institute’s Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial. Researchers examined baseline levels of certain dietary nutrients and metabolites found in patients’ blood before being diagnosed with prostate cancer. They then compared the levels between healthy patients and those later diagnosed with prostate cancer who died from the disease.

The findings showed men with elevated levels of a metabolite called phenylacetylglutamine (PAGln) were two to three times more likely to be diagnosed with lethal prostate cancer. PAGIn is produced when gut microbes break down the amino acid phenylalanine, which comes from plant- and animal-based protein sources like meat, beans and soy.

Researchers also discovered a link between increased risk of aggressive prostate cancer and elevated levels of two animal-based nutrients: choline and betaine. These nutrients are found in red meat, egg yolks and high-fat dairy products.

PAGIn also messes with heart health

This is the first time gut microbiome metabolites have been studied clinically in prostate cancer outcomes. Previously, these nutrients and gut metabolites were studied in heart disease and stroke.

Dr. Stanley Hazen, a collaborator on the most recent study, was the first to identify PAGln’s association with increased cardiovascular disease risk.

“Interestingly, we found that PAGln binds to the same receptors as beta-blockers, which are drugs commonly prescribed to help lower blood pressure and subsequent risk of cardiac events,” says Hazen, director of Cleveland Clinic’s Center for Microbiome & Human Health. “This suggests that part of beta blockers’ potent efficacy may be due to blocking the metabolite’s activity.”

“New insights are emerging from large-scale clinical datasets that show use of beta-blockers is also associated with lower mortality due to prostate cancer,” Sharifi says. “We will continue to work together to investigate the possible mechanisms linking PAGln activity and prostate cancer disease processes in hopes of identifying new therapeutic targets for our patients.”

Further research will explore how reliable it is to use choline, betaine and PAGln as biomarkers of aggressive prostate cancer. Investigators will also determine how to use dietary interventions to regulate levels of these nutrients and metabolites and subsequently reduce patients’ disease risk.

Reducing prostate cancer risk

There are several diet and lifestyle modifications you can make to lower your risk of aggressive prostate cancer. Maintaining a healthy weight is important since obesity can raise your risk of developing faster-growing forms of prostate cancer.

Make sure you eat a healthy diet that’s low in processed foods and added sugars that wreak havoc on gut health. Try to avoid foods containing choline, betaine and PAGIn, including red meat, beans, soy, egg yolks and high-fat dairy. And you may want to add a cup or two of green tea to your daily routine since studies show men who consume green tea regularly are less likely to develop prostate cancer.

There is one exception you should make on the dairy front. Eating fermented dairy products like yogurt, Greek yogurt, sour cream and kefir could actually lower your risk of prostate cancer because of the probiotics they contain. These good bacteria help balance your gut microbiome, which has been shown to reduce the risk of several kinds of cancer, including prostate.

Sources:

Cleveland Clinic Study Links Gut Microbiome and Aggressive Prostate Cancer — Cleveland Clinic

Key Statistics for Prostate Cancer — American Cancer Society

Survival Rates for Prostate Cancer — American Cancer Society

Prostate Cancer Risk Factors — American Cancer Society

Prostate cancer in young men: More frequent, more aggressive? — ScienceDaily

Prostate cancer in young men: an important clinical entity — Nature Reviews Urology