From:  The impact of polyphenol-rich dark fruits on pain and inflammation in osteoarthritis: a systematic review and meta-analysis

 Outcomes assessed and summary of main findings.

AuthorPrimary outcomesSecondary outcomesMain findings (summary)
Du et al. [66]WOMAC total and subscales (pain, stiffness, difficulty performing daily activities)Gait spatiotemporal parameters; inflammatory biomarkers (TNF-α, IL-1β, IL-6, IL-10, IL-13, MMP-3, MMP-13, MCP-1); blood pressure; BMIBlueberry supplementation was associated with significant within-group reductions in WOMAC total score and several subscales, plus improvements in selected gait parameters. However, there were no significant between-group differences in pain, stiffness, or difficulty performing daily activities at any time point, and no significant biomarker changes were demonstrated, apart from non-significant trends for IL-13 and MCP-1.
Basu et al. [67]Systemic inflammatory biomarkers and lipid peroxidation productsObesity-related hormones; osteocalcin; body weight; waist circumferenceCompared with control, strawberry supplementation significantly reduced hs-TNF-α, sTNF-R2, 4-HNE, and conjugated dienes. No significant changes were seen in body weight, waist circumference, obesity-related hormones, or osteocalcin.
Schell et al. [68]Pain outcomes (ICOAP, VAS) and serum inflammation/cartilage biomarkersHAQ-DI and VAS healthCompared with control, strawberry supplementation significantly reduced constant, intermittent, and total knee pain on ICOAP and improved HAQ-DI. IL-6, IL-1β, and MMP-3 were also significantly lower, while VAS pain, hs-CRP, nitrite, and MMP-8 did not differ significantly between phases.
Schumacher et al. [69]WOMAC total and subscalesWalking time; rescue acetaminophen use; hsCRP; urate; creatinineWOMAC total, pain, and function improved during tart cherry treatment, and hsCRP declined. However, the between-treatment difference versus placebo for WOMAC was not statistically significant. Walking time, acetaminophen use, urate, and creatinine were unchanged.
Kuehl et al. [70]Inflammatory biomarkers (CRP, IL-6, IL-10, TNF-α)Pain scores (WOMAC and VAS)Tart cherry juice was associated with a significant reduction in CRP only after exclusion of one extreme post-test outlier. IL-6, IL-10, and TNF-α did not change significantly. Pain scores were measured, but detailed between-group pain results were not clearly reported in the publication.
Ghoochani et al. [71]WOMAC total score and subscalesMMP-1, MMP-13, and glutathione peroxidaseWithin the pomegranate group, WOMAC total score, stiffness, and physical function improved over 6 weeks, but pain did not. Between-group WOMAC differences were not significant. MMP-13 was significantly lower than control at study end, and glutathione peroxidase increased within the intervention group despite baseline imbalance.

Note. Summary statements prioritize between-treatment interpretation where possible and explicitly distinguish this from within-group change when the original paper did not show a clear between-group effect. WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index.