Effects of Vaccinium meridionale Swartz (agraz) Supplementation on Inflammatory and Oxidative Stress Markers in Patients With Metabolic Syndrome: A Systematic Review of Randomized Controlled Clinical Trials.

Vaccinium meridionale Swartz (commonly known as agraz or Andean blueberry is a wild fruit native to Colombia and rich in anthocyanins. In this systematic review, we evaluated the effects of agraz supplementation on inflammatory and oxidative stress markers in individuals with metabolic syndrome (MetS). A comprehensive literature search was conducted using PubMed, Scopus, ISI Web of Science, and Google Scholar for articles published up to March 2024, without restrictions on language, publication date, or geographical region. Among the 2,616 records identified initially through the database searches, 6 studies were included in this review. The risk of bias in the included studies was assessed using the Cochrane Collaboration's tool. Six randomized controlled trials (RCTs) involving 252 participants were analyzed. The intervention durations ranged from 21 days to 4 weeks, and the agraz supplementation doses were between 200 and 250 mL per day. Agraz supplementation significantly reduced urinary and serum levels of 8-hydroxy-2'-deoxyguanosine (8-OHdG). However, among 3 studies examining high-sensitivity C-reactive protein (hs-CRP) levels, only 1 reported a statistically significant decrease in its levels. No significant effects were observed for other inflammatory or oxidative stress biomarkers. Agraz supplementation notable reduced urinary and serum 8-OHdG levels, suggesting potential antioxidant effects; however, its effect on hs-CRP levels remains inconclusive. No significant changes were observed in the levels of the other biomarkers. Further RCTs with larger doses and longer durations are necessary to confirm these findings and to clarify the therapeutic potential of agraz in MetS.

Trial registration: PROSPERO Identifier: CRD42022369292.