Background: Maternal diet during pregnancy may play a role in infant health outcomes via the maternal microbiota. We assessed the association of the maternal diet index for the Mediterranean area (MDI-med) with infant gut microbiota at 1 month of life. Methods: The MAMI study is a longitudinal birth cohort in the Mediterranean area. In this work, a cross-sectional study, including 120 mother–infant dyads with available maternal diet and infant microbiota at 1-month-old data, was undertaken. The MDI developed in the US (MDI-US) was adapted for the MAMI cohort (MDI-med). Stratification based on extreme values resulted (22 in the “lower” MDI-med group and 23 in the “upper” group from the mean). Relative microbial abundances and alpha (microbial richness and diversity indexes) and beta diversity (Bray–Curtis distance matrix) were compared between the groups. Results: Higher maternal daily vegetable intake and lower red meat intake were the characteristics of the “upper” MDI-med group. Significantly lower microbial diversity (Shannon and InvSimpson index (p = 0.01)), but no changes in richness (Chao1 index) nor in beta-diversity, using Bray–Curtis distance, were observed in the “upper” group, compared to the “lower” MDI-med group. A higher relative abundance of the Bifidobacterium genus (Actinomycetota phylum) was associated with maternal daily vegetable and yogurt intake. Conclusion: Reduced infant microbial diversity at 1 month of age was associated with “upper” MDI-med scores. Higher maternal intakes of vegetables and yogurt were associated with higher relative abundances of the Bifidobacterium genus in the infant gut. Further studies are needed to understand the link between pregnancy diet, infant microbiota, and health outcomes.

Background/Objectives: An adapted version of an online pictorial food frequency questionnaire (FFQ), VioScreen-Allergy, assesses total dietary intake and intake of allergens and foods in the maternal diet index (MDI), linked to offspring allergy. This study assessed intermethod reliability, test–retest reliability, and external validity of the VioScreen-Allergy. Methods: Females of childbearing age were recruited at Denver Health and Children’s Hospital, Colorado, USA, and were asked to complete four 24 h recalls and two VioScreen-Allergy FFQs over the course of a month. All those with at least two 24 h dietary recalls and both VioScreen-Allergy assessments were analyzed. Energy-adjusted and non-adjusted linear mixed models (1) compared MDI scores and intake of nutrients and allergens as measures of intermethod reliability; (2) evaluated VioScreen-Allergy test–retest reliability as differences between repeated measurements; and (3) assessed external validity by modeling associations between VioScreen-Allergy-derived intake of beta-carotene and orange vegetables and Veggie Meter^®-assessed skin carotenoids. Bonferroni corrections controlled multiple comparisons within the assessment. Results: Of 53 participants enrolled, 25 demographically dissimilar participants were included in the analysis. There were no significant differences between 24 h recall and VioScreen-Allergy mean intakes of macronutrients, micronutrients, allergens, or MDI, except for Vitamin C, niacin, and cashew allergen protein. There were no significant differences between repeated measurements of VioScreen-Allergy, either energy-adjusted or unadjusted. Both beta-carotene and orange vegetable servings were significantly associated with Veggie Meter^®. Conclusions: Although non-significance could have been due to low power, clinical as well as statistical assessments of intermethod reliability, test–retest reliability, and external validity suggest that VioScreen-Allergy has reasonable utility for trials assessing food allergens and MDI in the context of overall intake. The VioScreen questionnaire can also be used in future studies to assess macro- and micronutrient intake. Additional validation studies assessing different portion sizes and foods eaten by infants and young children are currently undergoing.

Background/Objectives: The complementary feeding period is a critical window for shaping infant diet, gut microbiota, and immune development. While allergic symptoms often emerge in the first year of life, the effects of specific foods, such fruits, on infant allergy symptoms, inflammation, immunity and associated microbiota remain unclear. This study aimed to assess the impact of daily blueberry consumption during the complementary feeding period on allergy-related symptoms, immune biomarkers, and gut microbiota in breastfed U.S. infants. Methods: In a double-blind, randomized, placebo-controlled trial, infants from the Denver metro area were assigned to receive up to 10 g/day of freeze-dried blueberry powder or an isocaloric placebo from 5 to 12 months of age. Stool, blood, and caregiver-reported allergy-related symptom data were collected at baseline and study end. Results: Of the 76 infants enrolled, 61 completed the study (Blueberry: n = 30; Placebo: n = 31). While more infants in the blueberry group had allergy-related symptoms at baseline, they had significantly different longitudinal symptom trajectories than the placebo (p = 0.05), showing a greater resolution rate of symptoms by study end. Pro-inflammatory serum IL-13 levels were significantly reduced (p = 0.035) and anti-inflammatory IL-10 levels borderline increased (p = 0.052) in the blueberry group. However, changes in allergy symptoms were not significantly associated with IL-10 or IL-13. The relative abundances of Lacticaseibacillus, Blautia, and Peptostreptococcaceae at 12 months were negatively correlated with IL-10, while Lactobacillus, Clostridiaceae, and Megasphaera were positively associated. IL-13 was positively associated with Citrobacter and negatively associated with Anaerostipes and Blautia. Conclusions: The consumptio9n of blueberries as an early complementary food may improve resolution of allergy symptoms, modulate immune biomarkers, and promote beneficial shifts in gut microbiota during infancy. Future research should aim to identify the specific bioactive components of blueberries responsible for these effects and explore the potential of other complementary foods to favorably influence developing biological systems involved in microbiota and immune development.