556-P: The Relationship between Short-Chain Fermentable Carbohydrates (FODMAPs) , Gut Microbiome, and Glucose Intolerance: An Exploratory Analysis

Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs) are fermentable short-chain carbohydrates that include fructans, galactooligosaccharides (GOS) , lactose, excess fructose, mannitol and sorbitol. Low FODMAP diets in irritable bowel syndrome were associated with reductions in metabolically beneficial, short-chain fatty acids (SCFA) - producing bacteria. We examined the interactions between FODMAP, gut microbiota and glucose tolerance in this exploratory analysis. Twenty subjects underwent oral glucose tolerance tests (OGTT) with C peptide measurements. Ten were classified as normal glucose tolerant (mean ±SD 55±years, body mass index (BMI) 22.7­±2.5 kg/m², 2-hour plasma glucose 5.7±1.0 mmol/L) and with impaired glucose tolerance (58±­5 years, BMI 23.5±2.9 kg/m², 2-hour glucose 9.0±0.9 mmol/L) . FODMAPs and macronutrients were assessed from 3-day food diaries. Fecal samples were collected for microbiome analysis. Total FODMAPs were positively correlated to presence of Dorea (r=0.49, p=0.027) . For individual FODMAP items, lactose was positively correlated with Akkermansia (r=0.54, p=0.013) , Bifidobacterium (r=0.42, p=0.037) and negatively correlated with Shigella (r=0.35, p=0.031) in both groups. GOS were positively correlated with Lactobacillus (r= 0.21, p=0.006) and negatively with Shigella (r=0.28, p=0.043) . In the whole group, lower insulin resistance as shown by homeostasis model assessment HOMA2-IR was associated with higher abundance of Bifidobacterium logum (r=0.48, p=0.01) . HOMA2-beta showed correlation with Dorea (r=0.43, p=0.056) . FODMAPs increased the health-promoting microbiota (e.g. Dorea, Lactobacillus, Akkermansia, and Bifidobacterium) . These SCFA promoting microbiota were associated with lower insulin resistance and improved beta-cell function while suppressing the growth of opportunistic pathogens, such as Escherichia spp.