(OR24-01-26) Zinc-Biofortified Maize Improves Cellular Zinc Status and Elicits Age-Dependent Ecological Adaptations in the Host-Microbiome Axis

Objectives: To evaluate the systemic physiological and multi-omic microbial impacts of zinc-biofortified maize (F3) on women and children in rural Guatemala.

Methods: An 8-week efficacy trial included 30 households (16 F3; 14 control) with women (18-49y) and children (12-59m). We evaluated blood (linoleic to dihomo-γ-linolenic acid [LA:DGLA], hsCRP), fecal calprotectin, SCFAs, and 16S rRNA microbiomes using linear mixed-effects models and PERMANOVA (FDR-corrected q-values denote significance).

Results: F3 significantly reduced LA:DGLA in children (baseline 4.13±0.22 SE to 3.39±0.18) and mothers (3.85±0.18 to 3.16±0.15) vs. controls (q=0.0115), confirming cellular zinc uptake. Beyond this shared success, physiological responses diverged by age. F3 pediatric microbiomes underwent profound structural reorganization: significant longitudinal beta-diversity shifts (PERMANOVA q=0.006), reduced richness and phylogenetic breadth (Observed ASVs q=0.005; Faith's PD q=0.031), and improved evenness (q=0.008). Systemically, F3 children showed trending immune mobilization via elevated hsCRP (interaction q=0.055) and fever (37.5% vs. 7.1%, p=0.086). Conversely, maternal microbiomes maintained structural stability (beta-diversity p >0.91) but adapted functionally. F3 mothers had significantly increased propionate vs. controls (q=0.014), while acetate increases were non-significant (q=0.102). Integration revealed a strong acetate-propionate network (mothers rho=0.70, q=0.002; children rho=0.64, q=0.006). Maternal fecal calprotectin was significantly higher in F3 vs. controls at endline (1.96 [IQR 1.54-15.67] vs. 0.62 [IQR 0.18-8.25] ug/g, q=0.031), indicating targeted mucosal immunity. Pediatric beta-lactam resistance pathways showed non-significant contractions (q=0.125).

Conclusions: Zinc-biofortified maize effectively improves cellular zinc status but acts as a dual-modulator of the host-microbiome axis. It reveals profound age-dependent plasticity: driving targeted mucosal immunity and metabolic adaptation in mothers, while triggering structural microbial reorganization and systemic immune trends in children.

Funding Sources: Light a Single Candle Foundation