Abstract
Fermented dairy products, including yogurt, kefir, and probiotic milk, are increasingly recognized as functional foods because of their potential contribution to cardiometabolic health improvement. This systematic review and meta-analysis was conducted to evaluate the influence of fermented dairy intake on glycemic control, lipid metabolism, and gut microbiota-related outcomes in adult populations. A structured literature search was conducted across PubMed/MEDLINE, Scopus, Web of Science, and CENTRAL following the PRISMA 2020 reporting framework. Only randomized controlled trials (RCTs) evaluating fermented dairy interventions and reporting cardiometabolic outcomes were included in this study. Six eligible RCTs were identified for qualitative synthesis, of which 5 provided sufficient quantitative data for meta-analysis. The findings demonstrated that the consumption of fermented dairy was most consistently associated with improved glycemic outcomes, particularly reductions in fasting plasma glucose and glycated hemoglobin (HbA1c), with stronger effects observed among metabolically compromised individuals. Quantitative pooling was feasible only for glycemic outcomes because the included trials had sufficiently comparable effect estimates.In contrast, the effects on lipid parameters were less consistent and generally modest. Given the considerable variability in intervention characteristics and outcome reporting, lipid-related findings were synthesized narratively rather than quantitatively Although only a limited number of studies have assessed gut microbiota-related outcomes, the available evidence suggests that the modulation of microbial composition and metabolite production may represent an important mechanistic pathway linking the intake of fermented dairy products to metabolic health. Overall, current evidence suggests that fermented dairy may serve as a promising nutritional approach to support cardiometabolic health, particularly through enhanced glucose regulation. Nevertheless, variations in study design, intervention characteristics, and microbiome assessment methods highlight the need for larger, long-term, and methodologically standardized clinical trials to confirm these findings and better define the underlying biological mechanisms.

Key words: Cardiometabolic health; Fermented dairy; Glycemic control; Gut microbiota; Randomized controlled trials.