Passion fruit peel extract may improve knee health

By Stephen Daniells

- Last updated on GMT

Related tags Anti-inflammatory Non-steroidal anti-inflammatory drug Osteoarthritis

Extracts from the peel of purple passion fruit may reduce measures of pain and stiffness in people suffering from knee osteoarthritis, says a new randomized, double-blind, placebo-controlled trial.

Writing in Nutrition Research​, scientists from Iran, the USA, and New Zealand report that, according to scores on the widely accepted WOMAC scale, 60 days of supplementation with the passion fruit peel extract reduced pain and stiffness of the knees by about 18 percent.

If additional studies support the effects of the passion fruit peel, it could see the extract emerge as a potential replacement for pharmaceutical non-steroidal anti-inflammatory drugs (NSAIDs). Some NSAIDs, which are among the most frequently prescribed medications worldwide, have been linked with gastrointestinal toxicity, increased blood pressure, and increased risk of cardiovascular disease.

“The ability for passion fruit peel extract to act as an anti-inflammatory agent, antioxidant, and MMP inhibitor may explain its reduction in osteoarthritis pathology in the patients studied in this double-blinded, placebo-controlled study,”​ wrote researchers led by Ronald Watson from The University of Arizona and Southwest Scientific Editing and Consulting, Arizona.

“The passion fruit peel extract supplementation should help patients to reduce their reliance upon NSAIDs that may have undesirable side effects in the treatment of osteoarthritis symptoms,”​ they added.

Aging populations

As populations age, the burden of osteoarthritis is growing. Over 20 million Americans suffer from osteoarthritis, and it is reported to be second only to ischemic heart disease as a cause of work disability in men over 50. According to the Center for Disease Control, the direct and indirect costs are estimated to be approaching $90 billion. Elsewhere, the figures are equally worrying, with approximately seven million people in the UK alone are reported to have long-term health problems associated with arthritis.

The market for joint health ingredients is dominated by glucosamine – now a $2bn (€1.47bn) global blockbuster. It is most commonly blended with chondroitin so the two have become linked in the minds of many consumers.

Study details

Dr Watson and his co-workers recruited 33 people with osteoarthritis in the knee and randomly assigned them to receive either placebo or the passion fruit peel extract (150 mg per day) for two months.

At the end of the study the researchers report that clinical symptoms of osteoarthritis, measured using the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index, showed significant improvement in the passion fruit group, compared with placebo. In addition to the improvements in the pain and stiffness scores, the researchers note that physical function and composite WOMAC score improved by 19.6 and 19.2 percent, respectively.

Commenting on the potential bioactives, Watson and his co-workers pointed to the passion fruit peel extract’s “unique mixture of bioflavonoids with antioxidant and inflammatory activity”​.

The study was funded by Southwest Scientific Editing and Consulting, whereas New Zealand’s Industrial Research Limited provided the extract. Researchers from both companies were involved in the study.

Source: Nutrition Research
Volume 30, Pages 601-606
“Oral intake of purple passion fruit peel extract reduces pain and stiffness and improves physical function in adult patients with knee osteoarthritis “
Authors: R. Farid, Z. Rezaieyazdi, Z. Mirfeizi, M.R. Hatef, M. Mirheidari, H. Mansouri, H. Esmaelli, G. Bentley, Y. Lu, Y. Foo, R.R. Watson

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