Mitchell, Cassie M.Davy, Brenda M.Ponder, Monica A.McMillan, Ryan P.Hughes, Michael D.Hulver, Matthew W.Neilson, Andrew P.Davy, Kevin P.2021-09-272021-09-272021-09-17Mitchell, C.M.; Davy, B.M.; Ponder, M.A.; McMillan, R.P.; Hughes, M.D.; Hulver, M.W.; Neilson, A.P.; Davy, K.P. Prebiotic Inulin Supplementation and Peripheral Insulin Sensitivity in adults at Elevated Risk for Type 2 Diabetes: A Pilot Randomized Controlled Trial. Nutrients 2021, 13, 3235.http://hdl.handle.net/10919/105073Prediabetes affects 84.1 million adults, and many will progress to type 2 diabetes (T2D). The objective of this proof-of-concept trial was to determine the efficacy of inulin supplementation to improve glucose metabolism and reduce T2D risk. Adults (<i>n</i> = 24; BMI: 31.3 ± 2.9 kg/m²; age: 54.4 ± 8.3 years) at risk for T2D were enrolled in this controlled feeding trial and consumed either inulin (10 g/day) or placebo (maltodextrin, 10 g/day) for six weeks. Assessments included peripheral insulin sensitivity, fasting glucose, and insulin, HOMA-IR, in vivo skeletal muscle substrate preference, <i>Bifidobacteria</i> copy number, intestinal permeability, and endotoxin concentrations. Participant retention was 92%. There were no baseline group differences except for fasting insulin (<i>p</i> = 0.003). The magnitude of reduction in fasting insulin concentrations with inulin (<i>p</i> = 0.003, inulin = Δ-2.9, placebo = Δ2.3) was attenuated after adjustment for baseline concentrations (<i>p =</i> 0.04). After adjusting for baseline values, reduction in HOMA-IR with inulin (inulin = Δ-0.40, placebo=Δ0.27; <i>p =</i> 0.004) remained significant. <i>Bifidobacteria</i> 16s increased (<i>p =</i> 0.04; inulin = Δ3.1e⁹, placebo = Δ-8.9e⁸) with inulin supplementation. Despite increases in gut <i>Bifidobacteria,</i> inulin supplementation did not improve peripheral insulin sensitivity. These findings question the need for larger investigations of inulin and insulin sensitivity in this population.application/pdfenCreative Commons Attribution 4.0 Internationaldietary fiberprebioticsinulindiabetesmetabolismgut microbiotaArticle - Refereed2021-09-25https://doi.org/10.3390/nu13093235