FIGURE 6.

Forest plots for randomized controlled trials of acute vinegar intake on postprandial blood glucose in nonhealthy adults. Acute interventions with vinegar had a main effect of −0.53 (95% CI, −0.92 to −0.14; P = 0.01) on the postintervention postprandial blood glucose iAUC (n = 67) in nonhealthy subjects. A random-effects model was used to calculate standardized mean differences (squares), 95% CIs (horizontal lines), and summary effects (SMD; diamond). The study weight (expressed as a percentage) indicates the relative contribution of an individual study to the overall pooled effect size. Between-study heterogeneity was calculated using the I² statistic. A P value ≤ 0.05 was considered statistically significant. When interpreting SMDs (or effect sizes) values <0.40 were categorized as having a small effect size, values 0.40 to 0.70 as having a moderate effect size, and values >0.70 as having a large effect size. Liatis et al. (32) used (study a) a high-GI meal and (study b) a low-GI meal. Mitrou et al. (44, 45) published results in the (study a) Journal of Diabetes Research (Mitrou et al. 45) and (study b) European Journal of Clinical Nutrition (Mitrou et al. 44). Abbreviations: GI, glycemic index; iAUC, incremental AUC; IGT, impaired glucose tolerance; IR, insulin resistant; SMD, standard mean difference; T2D, type 2 diabetes.