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Background: The infant gut microbiome undergoes rapid changes in the first year of life, supporting normal development and long-term health. Although diet shapes this process, the role of fibers in complementary foods on gut microbiome maturation is poorly understood., Objectives: We explored how the transition from human milk to fibers in complementary foods shapes the taxonomic and functional maturation of the gut microbiome within the first year of life., Methods: We assessed the longitudinal and cross-sectional development of infant gut microbiomes (N = 68 infants) and metabolomes (N = 33 infants) using linear mixed models to uncover their associations to dietary fibers and their food sources. Fiber intakes were assessed with 3-d food records (months 3, 6, 9, and 12) relying on CODEX-compliant fiber fraction values, and questionnaires tracked the overall complementary food introduction. Bacterial species were identified and quantified via MetaPhlAn2 from metagenomic data, and metabolomic profiles were obtained using 4 LC-MS methods., Results: We identified 176 complementary food fiber-bacterial species associations. First plant-based fibers associated with microbiota compositions similar to breastfeeding, and further associated with aromatic amino acid-derived metabolites, including 5-hydroxyindoleacetic acid (total dietary fiber - complementary foods (g) - β = 3.50, CI: 2.48, 4.52, P = 6.53 × 10 -5 ). Distinct fibers from different food categories showed unique associations with specific bacterial taxa. Key species, such as Faecalibacterium prausnitznii, associated with oat fibers (g/MJ, β = 2.18, confidence interval: 1.36, 2.84, P = 6.12 × 10 -6 ), reflective of maturing microbial communities. Fiber intake during weaning associated with shifts in metabolite profiles, including immunomodulatory metabolites, with fiber effects observed in a source- and timing-dependent manner, implicated in gradual microbiome diversification., Conclusions: Introducing complementary dietary fibers during the weaning period supports gut microbiome diversification and stabilization. Even minor dietary variations shows significant associations with microbial taxa and functions from the onset of weaning, highlighting the importance of infant dietary recommendations that support the gut microbiome maturation during early life. This trial was registered at clinicaltrials.gov as registration number NCT01735123., Competing Interests: Conflict of interest TV has received speaker honoraria from Nestle Nutrition Institute (NNI)., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Background: Prospective longitudinal evidence considering the entire childhood food consumption in relation to the development of islet autoimmunity (IA or) type 1 diabetes is lacking., Objectives: We studied the associations of consumption of various foods and their combinations with IA and type 1 diabetes risk., Methods: Children with genetic susceptibility to type 1 diabetes born in 1996-2004 were followed from birth up to ≤6 y of age in the prospective birth cohort type 1 diabetes prediction and prevention study (n = 5674). Exposure variables included 34 food groups covering the entire diet based on repeated 3-d food records at ages 3 mo to 6 y. Endpoints were islet cell antibodies plus biochemical IA (n = 247), multiple biochemical IA (n = 206), and type 1 diabetes (n = 94). We analyzed associations between longitudinally observed foods and risk of IA/type 1 diabetes using a Bayesian approach to joint models in 1-food and multi-food models adjusted for energy intake, sex, human leukocyte antigen genotype, and familial diabetes., Results: The final multi-food model for islet cell antibodies plus biochemical IA included oats [hazard ratio (HR): 1.09; 95% credible interval (CI): 1.04, 1.14], banana (HR: 1.07; 95% CI: 1.03, 1.11), and cruciferous vegetables (HR: 0.83; 95% CI: 0.73, 0.94). The final model for multiple biochemical IA included, in addition to the above-mentioned foods, fermented dairy (HR: 1.42; 95% CI: 1.12, 1.78) and wheat (HR: 1.10; 95% CI: 1.03, 1.18). The final multi-food model for type 1 diabetes included rye (HR: 1.27; 95% CI: 1.07, 1.50), oats (HR: 1.15; 95% CI: 1.03, 1.26), fruits (HR: 1.05; 95% CI: 1.01, 1.09), and berries (HR: 0.67; 95% CI: 0.50, 0.93)., Conclusions: Higher consumption of oats, gluten-containing cereals, and fruits was associated with increased that of cruciferous vegetables with decreased risk of several type 1 diabetes-related endpoints when considering all the foods in combination. Further etiological and mechanistic studies are warranted., Competing Interests: Conflict of interest The authors report no conflicts of interest., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Gut dysbiosis and increased intestinal permeability have been reported to precede type 1 diabetes-related autoimmunity. The role of gut inflammation in autoimmunity is not understood., Objectives: This study aimed to assess whether gut inflammation markers are associated with risk of islet autoimmunity and whether diet is associated with gut inflammation markers., Methods: A nested case-control sample of 75 case children with islet autoimmunity and 88 control children was acquired from the Finnish Type 1 Diabetes Prediction and Prevention cohort. Diet was assessed with 3-d food records, and calprotectin and human β-defensin-2 (HBD-2) were analyzed from stool samples at 6 and 12 mo of age. Conditional logistic regression analysis was used in a matched case-control setting to assess risk of autoimmunity. Analysis of variance, independent samples t test, and a general linear model were used in secondary analyses to test associations of background characteristics and dietary factors with inflammation markers., Results: In unadjusted analyses, calprotectin was not associated with risk of islet autoimmunity, whereas HBD-2 in the middle (odds ratio [OR]: 3.23; 95% confidence interval [CI]: 1.03, 10.08) or highest tertile (OR: 3.02; 95% CI: 1.05, 8.69) in comparison to the lowest at 12 mo of age showed borderline association (P-trend = 0.063) with higher risk of islet autoimmunity. Excluding children with cow milk allergy in sensitivity analyses strengthened the association of HBD-2 with islet autoimmunity, whereas adjusting for dietary factors and maternal education weakened it. At age 12 mo, higher fat intake was associated with higher HBD-2 (β: 0.219; 95% CI: 0.110, 0.328) and higher intake of dietary fiber (β: -0.294; 95% CI: -0.510, -0.078), magnesium (β: -0.036; 95% CI: -0.059, -0.014), and potassium (β: -0.003; 95% CI: -0.005, -0.001) with lower HBD-2., Conclusions: Higher HBD-2 in infancy may be associated with higher risk of islet autoimmunity. Dietary factors play a role in gut inflammatory status., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)