Pomegranates: Fact or Fiction for Health Benefits?

Pomegranates have been scrutinized extensively regarding their potential benefits for conditions such as weight management, diabetes control, chronic obstructive pulmonary disease (COPD), prostate cancer, osteoarthritis, and rheumatoid arthritis. The high-profile legal battle between POM Wonderful,

Pomegranates have been scrutinized extensively regarding their potential benefits for conditions such as weight management, diabetes control, chronic obstructive pulmonary disease (COPD), prostate cancer, osteoarthritis, and rheumatoid arthritis.

The high-profile legal battle between POM Wonderful, a prominent pomegranate juice producer, and the Federal Trade Commission escalated all the way to the U.S. Court of Appeals, with the Supreme Court ultimately declining to hear the case. In this pivotal ruling, a judicial panel determined that numerous advertisements from POM contained misleading or outright false statements. The company had promoted medical research suggesting that regular intake of their products could treat, prevent, or lower the risk of serious conditions like heart disease, prostate cancer, and erectile dysfunction. However, the First Amendment does not shield deceptive advertising practices. This decision represented a significant setback for the company's billionaire proprietors, as the court mandated that claims about treating or preventing diseases must be backed by at least one randomized clinical trial.

Examining the broader medical literature on pomegranates reveals numerous review articles highlighting their wide-ranging health advantages, often illustrated with detailed diagrams depicting the fruit's medicinal properties.

A closer inspection, however, uncovers that these claims frequently rely on research such as investigations into the antiobesity properties of pomegranate leaf extract in mouse models. This raises two key issues: firstly, pomegranate leaves are not a typical part of human diets, and secondly, results from mice do not necessarily translate to humans.

When evaluating whether pomegranate consumption influences human body weight, a comprehensive analysis of all available randomized controlled trials—gold-standard human studies—shows no meaningful impact on body weight, body mass index (BMI), abdominal fat accumulation, or overall body fat percentage among participants assigned to pomegranate-based products.

Shifting focus to cardiovascular health, experts reviewed 25 clinical trials assessing parameters like cholesterol levels, blood pressure, endothelial function in arteries, plaque buildup in atherosclerosis, and platelet aggregation. Even the most rigorous studies failed to demonstrate significant benefits.

POM Wonderful sponsored research exploring pomegranate juice's effects on erectile dysfunction, yet it yielded no positive outcomes. Similarly, additional investigations reported no improvements in diabetes-related biomarkers or in managing chronic obstructive pulmonary diseases like emphysema. The company had hoped the juice's antioxidant properties would provide relief, but these effects were only observed in vitro, such as in test tubes or petri dishes. Surprisingly, a meta-analysis pooling data from 11 randomized controlled trials found no compelling evidence that pomegranate consumption substantially boosts total antioxidant capacity in human blood. This is because some of the most powerful antioxidants in pomegranates appear not to be absorbed effectively into the human bloodstream. Consequently, pomegranate supplements showed no influence on oxidative stress markers in tissue biopsies from prostate cancer patients. The real question remains: does it impact the cancer itself?

Proponents argue that the most robust evidence for pomegranates' anticancer potential stems from prostate cancer research. Regrettably, initial encouraging findings could not be replicated in more definitive trials. For instance, a randomized controlled trial revealed that daily pomegranate consumption had no effect on prostate-specific antigen (PSA) levels, which serve as an indicator of tumor advancement. Furthermore, a randomized, double-blind, placebo-controlled study detected virtually no differences in prostate cancer progression rates between treatment and placebo groups.

Researchers had anticipated benefits from the anti-inflammatory qualities of pomegranate juice, but these were again limited to in vitro demonstrations. In human subjects, a 2016 meta-analysis of five randomized controlled trials concluded that pomegranate juice exerted no significant influence on C-reactive protein (CRP) levels, a primary inflammation indicator. Nonetheless, examining the forest plot reveals that all five studies trended toward reduced CRP levels, with combined data nearly achieving statistical significance.

A more recent 2020 meta-analysis, incorporating seven studies, surpassed the threshold for statistical significance, revealing notable reductions not only in CRP but also in two additional inflammatory markers.

These findings suggest that pomegranate juice might indeed assist in managing inflammatory conditions, though rigorous testing is essential to confirm this.

Osteoarthritis entails the progressive breakdown of cartilage that cushions joints, most commonly affecting the knees. Applying pomegranate extract directly to human osteoarthritic cartilage samples in laboratory settings demonstrated protective effects against degradation. Compared to baseline cartilage breakdown rates, inflammatory agents tripled the damage, but escalating doses of pomegranate extract progressively mitigated this destruction.

While promising in petri dishes, the critical question is whether pomegranate's active compounds enter the bloodstream upon consumption and reach the joints. Studies confirmed bioavailability of cartilage-protective elements, at least in rabbit models, hinting at pomegranates as a potentially safe, side-effect-free alternative to conventional medications. But does it truly work in humans?

The inaugural clinical trial on pomegranate juice for osteoarthritis lacked a placebo group, instead randomizing participants to juice or no intervention. Juice consumers experienced reduced stiffness and improved physical function, but improvements were not statistically superior to the no-treatment arm.

On the verge of dismissing pomegranates entirely, attention turned to a study on hydrolyzable tannins-rich pomegranate extract suppressing inflammation and joint damage in rheumatoid arthritis models. Disappointingly, it was funded by POM Wonderful and conducted in mice with induced joint damage.

An open-label trial involved eight patients with active rheumatoid arthritis taking daily pomegranate extract; six completers noted fewer tender joints. Without a control group, however, it's impossible to attribute changes solely to the intervention.

At last, a randomized, double-blind, placebo-controlled trial provided clarity. Participants were evenly divided: half received pomegranate extract unknowingly, while the other half got a placebo. Results showed marked improvements in swollen joints, tender joints, pain severity, disease activity scores, health assessment questionnaires, and morning stiffness versus placebo. For those with rheumatoid arthritis, incorporating pomegranates into the diet is advisable. Rather than supplements, whole fruit is preferable, as lab testing of 19 pomegranate products found most lacking authentic pomegranate content—only six proved genuine.