In recent years there’s been a growing interest in the potential effects of certain beverages for people who have rheumatoid arthritis (RA). As the authors of a review published in the journal Nutrients put it, “Beverages have a key role within the mosaic of autoimmunity in RA and potential to alter the microbiome, leading to downstream effects on inflammatory pathways."

Beverages, along with diet and other lifestyle factors, can influence many processes in the body that affect diseases, the authors note, citing the way coffee or tea seem to decrease inflammation while other drinks alter the gut microbiome, which interacts with the immune system.

Pomegranate Juice Is Especially Intriguing for RA

Juices from fruits rich in naturally occurring antioxidants found in certain plants, known as polyphenols, have gotten extra attention from researchers. The Nutrients authors wrote that fruit juices have been linked to beneficial effects for several conditions, including diabetes, inflammatory bowel disease, atherosclerosis, and certain metabolic disorders.

Pomegranates especially have been a research focus. These deep red fruits with hard skin surrounding ruby-red seeds (known as arils) are being called a superfood. Their juice, once a niche product, can now be purchased in many supermarkets, including Kroger, and other stores that sell groceries, like Target.

Potential Health Benefits of Pomegranate Juice

Research on mice has shown that pomegranate extract reduces the severity of collagen-induced arthritis, joint inflammation, and levels of the blood inflammatory marker interleukin 6 (IL-6).

Other studies have looked into the juice’s possible effect on heart disease, a condition that's considered a comorbidity for people with RA. Most of those studies have been done in test tubes or in mice, but a small number have been done in humans. One study, published in the British Journal of Nutrition, found a significant decrease in triglycerides, a fat found in the blood, after subjects took 400 milligrams (mg) of pomegranate seed oil a day for one month. (Participants' total blood cholesterol did not go down.)

Early but Promising Anti-Inflammation Effects

In a review published in Advanced Biomedical Research, Iranian scientists called the pomegranate “a potent antioxidant,” and said the various compounds found in the fruit have antihypertensive and anti-inflammatory properties, among other benefits.

A promising study published in the European Journal of Clinical Nutrition compared subjects given two 250 mg capsules of pomegranate extract a day with those taking a placebo. At the end of two months, people taking the extract reported less joint swelling and pain intensity, plus higher blood levels of glutathione peroxidase (GPx), which helps protect against oxidative damage. (C-reactive protein, erythrocyte sedimentation rate, and other important blood markers remained unchanged.)

A meta-analysis of twelve studies, published in The International Journal of Clinical Practice in August 2021, found that human, animal and in vitro research “indicated the beneficial effects of pomegranate on clinical symptoms, inflammatory and oxidative factors in RA” and that pomegranate can help manage “RA complications by reducing the inflammation and oxidative stress.” Researchers also noted that no significant “unfavourable results following pomegranate consumption were reported.”

More Robust Studies Are Still Needed

The authors of the study in The International Journal of Clinical Practice note that more clinical research would be justified. Experts caution that while early findings are promising for people with RA, larger studies in humans are needed to confirm them and provide better guidance on the amount and form of pomegranate or its juices that might be most effective.

Pomegranate and Possible Drug Interactions

Further complicating the picture are questions about whether pomegranate juice, like grapefruit juice, might affect the absorption rates of commonly used medications. “The absorption issue for drugs is a potential problem with pomegranate juice,” says Gustavo Carbone, MD, a rheumatologist at the University of Miami Health System in Florida. That’s because the fruit has been shown in the lab to interfere with CYP3A4 and CYP2C9, the same intestinal enzymes that grapefruit juice is known to inhibit.

The list of drugs that should not be taken with grapefruit juice is long. It includes some statin drugs that lower cholesterol, including Zocor (simvastatin), Lipitor (atorvastatin), and Pravachol (pravastatin) some blood pressure-lowering drugs, like Afeditab CR (nifedipine); some anti-anxiety medications, such as BuSpar (buspirone) anti-arrhythmia medications like Cordarone (amiodarone); and others such as cyclosporine, according to a review of research published in the Canadian Medical Association Journal, which is no longer commonly used to treat RA.

The U.S. Food and Drug Administration (FDA) warns that drinking grapefruit juice when you’re on these medications prevents the drug from being fully metabolized, so more might enter the bloodstream and stay there longer, resulting in potentially dangerous levels of the drug in your body and in additional side effects.

Be Cautious and Careful for Now

It’s less clear whether pomegranate juice has the same effect, because few studies have been done in people. Research published in the European Journal of Drug Metabolism and Pharmacokinetics concludes that, while it's possible that pomegranate juice may create drug metabolism issues, no one can say for sure without more research.

In one Korean study testing both pomegranate and grapefruit juices with the statin drug Zocor (simvastatin), for example, published in the same journal in February 2015, the grapefruit juice affected the medication but the pomegranate juice did not.

Still, until additional research clarifies the matter, if your doctor has told you to steer clear of grapefruit juice because of a medication you're taking, you may want to avoid the seedy pomegranate fruit along with its juice and extracts too —and have an apple instead.