Background: Apple cider vinegar (ACV) is a naturally fermented beverage with potential metabolic health benefits; however, its effects on weight loss remain controversial. This systematic review and meta-analysis of randomized controlled trials (RCTs) was conducted to assess the effect of ACV on anthropometric measurements in adults. Methods: We performed a systematic search of PubMed, Web of Science, Scopus, and CENTRAL up to March 2025 for randomized controlled trials (RCTs) in adults (≥18 years) evaluating the effects of ACV for ≥4 weeks on body composition parameters. Primary outcomes included changes in body weight, BMI, waist circumference, and other anthropometric measures. Risk of bias was assessed using the Revised Cochrane Risk-of-bias tool. Results: Out of 2961 reports screened, 10 RCTs comprising a total of 789 participants were eligible for inclusion in this meta-analysis. The pooled results using a random-effects model showed that daily ACV intake significantly reduced body weight [SMD: −0.39; 95% CI: −0.63, −0.15; p = 0.001; I² = 62%], BMI [SMD: −0.65; 95% CI: −1.05, −0.26; p = 0.001; I² = 83%], and WC [SMD: −0.34; 95% CI: −0.67, −0.02; p = 0.04; I² = 61%]. However, no significant effects of ACV were observed on the other body composition parameters analyzed. Sensitivity analyses excluding high-risk-of-bias studies confirmed the robustness of ACV’s beneficial effects on body weight and BMI. Subgroup analyses suggested that ACV consumption significantly improved anthropometric parameters when administered for up to 12 weeks, at a dose of 30 mL/day, and in adults who were overweight, obese, or had type 2 diabetes. Conclusions: Overall, this meta-analysis suggests that ACV supplementation may be a promising and accessible adjunctive strategy for short-term weight management in adults with excess body weight or metabolic complications.

Ultra-processed foods expose consumers to heat-induced contaminants like 5-hydroxymethylfurfural (5-HMF), which impairs intestinal homeostasis via oxidative stress and inflammation. This study quantified 5-HMF in bakery products and evaluated blueberry polyphenols’ capacity to attenuate 5-HMF-induced cellular stress in an in vitro Caco-2 intestinal model. 5-HMF levels in commercial bakery products were determined using a colorimetric assay and HPLC-UV. Differentiated Caco-2 cells were exposed to 5-HMF (0.4 mM) for 48 h, alone or co-treated with blueberry juice (15 µg/mL of phenol equivalents). ROS production, lipid accumulation, gene expression of antioxidant, lipid, and inflammatory markers, and NF-κB/ERK signaling pathways were analyzed. HPLC-UV accurately quantified 5-HMF in bakery products (exceeding 2 mg/100 g), revealing systematic overestimation by the colorimetric method. In Caco-2 cells, 5-HMF significantly increased ROS, lipid accumulation, inflammatory cytokines (NLRP3, IL1B, and IL18), and activated NF-κB and p-ERK. Co-treatment with blueberry juice reduced ROS and lipids, upregulated the NRF2 antioxidant pathway, and drastically suppressed NF-κB -mediated inflammation. 5-HMF induced markers of metabolic dysfunction, oxidative stress, and inflammation in the intestinal epithelial model. Polyphenol-rich blueberry juice attenuated 5-HMF-induced alterations at the tested concentration, suggesting a potential protective nutritional strategy against epithelial stress associated with food-processing contaminants.