Prebiotic Inulin Supplementation and Peripheral Insulin Sensitivity in adults at Elevated Risk for Type 2 Diabetes: A Pilot Randomized Controlled Trial.

Prediabetes 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 (n = 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, Bifidobacteria copy number, intestinal permeability, and endotoxin concentrations. Participant retention was 92%. There were no baseline group differences except for fasting insulin (p = 0.003). The magnitude of reduction in fasting insulin concentrations with inulin (p = 0.003, inulin = Δ-2.9, placebo = Δ2.3) was attenuated after adjustment for baseline concentrations (p = 0.04). After adjusting for baseline values, reduction in HOMA-IR with inulin (inulin = Δ-0.40, placebo=Δ0.27; p = 0.004) remained significant. Bifidobacteria 16s increased (p = 0.04; inulin = Δ3.1e9, placebo = Δ-8.9e8) with inulin supplementation. Despite increases in gut Bifidobacteria, inulin supplementation did not improve peripheral insulin sensitivity. These findings question the need for larger investigations of inulin and insulin sensitivity in this population.

糖尿病前期影响着8410万成年人，其中许多人会发展为2型糖尿病（T2D）。这项概念验证试验的目的是确定补充菊粉对改善糖代谢和降低2型糖尿病风险的功效。24名有2型糖尿病风险的成年人（体重指数：31.3 ± 2.9 kg/m²；年龄：54.4 ± 8.3岁）参与了这项对照喂养试验，他们分别服用菊粉（10克/天）或安慰剂（麦芽糊精，10克/天），持续6周。评估指标包括外周胰岛素敏感性、空腹血糖、胰岛素、胰岛素抵抗稳态模型评估（HOMA - IR）、体内骨骼肌底物偏好、双歧杆菌拷贝数、肠道通透性和内毒素浓度。参与者的留存率为92%。除了空腹胰岛素外，两组在基线时无差异（p = 0.003）。菊粉组空腹胰岛素浓度的降低幅度（p = 0.003，菊粉组 = Δ - 2.9，安慰剂组 = Δ2.3）在对基线浓度进行调整后减弱（p = 0.04）。在对基线值进行调整后，菊粉组HOMA - IR的降低（菊粉组 = Δ - 0.40，安慰剂组 = Δ0.27；p = 0.004）仍然显著。补充菊粉后双歧杆菌16s增加（p = 0.04；菊粉组 = Δ3.1×10⁹，安慰剂组 = Δ - 8.9×10⁸）。尽管肠道双歧杆菌增加，但补充菊粉并没有改善外周胰岛素敏感性。这些发现对在该人群中进一步大规模研究菊粉与胰岛素敏感性的必要性提出了质疑。