Impact of fiber-fortified food consumption on anthropometric measurements and cardiometabolic outcomes: A systematic review, meta-analyses, and meta-regressions of randomized controlled trials

The consumption of processed and refined food lacking in fiber has led to global prevalence of obesity and cardiometabolic diseases. Fiber-fortification into these foods can yield potential health improvements to reduce disease risk. This meta-analyses aimed to evaluate how fiber-fortified food consumption changes body composition, blood pressure, blood lipid-lipoprotein panel, and glycemic-related markers. Searches were performed from 5 databases, with 31 randomized controlled trial eventually analyzed. Hedges' g values (95% confidence interval [CI]) attained from outcome change values were calculated using random-effects model. Fiber-fortified food significantly reduced body weight (−0.31 [−0.59, −0.03]), fat mass (−0.49 [−0.72, −0.26]), total cholesterol (−0.54 [−0.71, −0.36]), low-density lipoprotein cholesterol (−0.49 [−0.65, −0.33]), triglycerides (−0.24 [−0.36, −0.12]), fasting glucose (−0.30 [−0.49, −0.12]), and HbA1c (−0.44 [−0.74, −0.13]). Subgroup analysis differentiated soluble fiber as significantly reducing triglycerides and insulin while insoluble fiber significantly reduced body weight, BMI, and HbA1c. Greater outcome improvements were observed with solid/semi-solid food state than liquid state. Additionally, fiber fortification of <15 g/day induced more health outcome benefits compared to ≥15 g/day, although meta-regression found a dose-dependent improvement to waist circumference (p-value = 0.036). Findings from this study suggest that consuming food fortified with dietary fiber can improve anthropometric and cardiometabolic outcomes.