The prebiotic interventions mostly consisted of inulin or oligosaccharides at dosages ranging from 2 to 45 grams per day and lasted from 6 to 104 weeks.

Prebiotics did not affect glycemic outcomes or lipid outcomes. Although body fat decreased with prebiotics compared to the control group (−1.27%), this was primarily driven by 2 of the 5 studies included in the analysis, and the other body composition outcomes (BMI and waist circumference) were similar between the groups.

The risk of bias was high in 5 studies, unclear in 4 studies, and low in 1 study.

The quality of evidence was very low for the primary outcomes (glucose, insulin, and glycemic control), and some of the control groups received maltodextrin, which may not be an appropriate placebo in prebiotic studies.^[1]

Are prebiotics beneficial for people with prediabetes? Original paper