The Effects of Sumac Consumption on Inflammatory and Oxidative Stress Factors: A Systematic Review of Randomized Clinical Trials

Background: Rhus coriaria L., commonly known as Sumac, is a plant from the Anacardiaceae family that is known for its high phytochemical content. These phytochemicals have the potential to effectively manage inflammation and oxidative stress. To explore the existing evidence on the impact of Sumac consumption on inflammation and oxidative stress, we conducted a systematic review of randomized controlled trials. Methods: We conducted a comprehensive search of Medline/PubMed, Scopus, and Web of Science from inception to August 2023 to identify relevant studies examining the effects of Sumac on biomarkers of inflammation and oxidative stress. The selected studies were assessed for risk of bias using the Cochrane tool. Results: A total of seven trials were included in this review. Among these trials, three focused on diabetes patients, while the remaining four involved individuals with fatty liver, overweight individuals with depression, and those with polycystic ovary or metabolic syndrome. Five studies reported the effects of Sumac on oxidative stress, with four of them demonstrating a significant reduction in malondialdehyde (MDA) levels and an increase in total antioxidant capacity (TAC) and paraoxonase 1 (PON1). Regarding inflammation, one study reported no significant difference in tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels between the intervention and control groups. The results for high-sensitivity C-reactive protein levels, reported in five trials, were inconsistent. Conclusion: Sumac consumption over time may positively affect oxidative stress, although short-term use shows minimal impact. While one study found no significant effect on IL-6 and TNF-α, hs-CRP levels could decrease or remain unchanged. Further meta-analyses are needed to fully understand Sumac's potential benefits in managing metabolic diseases.