661 - Vitamin D and its Role in Human Milk Oligosaccharide Production in Secretor Mothers

Publication Number: 661.7064

Molly Mead, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Susan T. Woollen, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Grace Pouch, Medical University of South Carolina, Charleston, SC, United States; Corinne Karch, Prisma Health, Columbia, SC, United States; Mathew Gregoski, MUSC Department of Public Health Sciences, Charleston, SC, United States; myla Ebeling, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Judy Shary, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Ann Abraham, Phoenix Children's Hospital, Phoenix, AZ, United States; Kennedy Spann, University of California, San Diego School of Medicine, La Jolla, CA, United States; Katherine E. Chetta, Medical University of South Carolina, Charleston, SC, United States; Bruce Hollis, Medical University of South Carolina, Charleston, SC, United States; John E. Baatz, Medical University of South Carolina College of Medicine, Charleston, SC, United States; Lars Bode, University of California, San Diego, La Jolla, CA, United States; Carol L. Wagner, Medical University of South Carolina College of Medicine, Charleston, SC, United States

Background: Human milk oligosaccharides (HMO) are complex carbohydrates that play a critical role in strengthening infant gut health, immunity, and neurodevelopment. Few studies have explored how maternal diet affects HMO production. Fewer have explored maternal vitamin D (vitD) status (serum biomarker 25(OH)D) during lactation and the effects on HMO biosynthesis.

Objective: We aimed to associate maternal vitD status during lactation and individual HMOs produced by secretor versus non-secretor mothers. We hypothesized that mothers with lower vitD status would have different HMO composition.

Design/Methods: This study is an expansion (n=88) of a posthoc analysis of a randomized, double-blind, comparative effectiveness and safety trial of three doses of vitD supplementation (400, 2400, and 6400 IU vitD3/day) in breastfeeding women and their infants as well as nonlactating control pairs (NICHD vitD lactation study (2007-2012) and Lactation Immune trial (2017-2021)). Concentrations of serum vitD and 19 predominant HMOs were measured at postpartum baseline (v1) and 4-month visits (v4). Secretor status is defined by the presence or near-absence of 2’-fucosylactose (2’FL). Spearman correlations associated serum 25(OH)D concentration (ng/ml), and total HMO weight (nmol) or percent of HMO per sample. Mann-Whitney U tests determined HMO differences between those with [25(OH)D] <= 32.7ng/mL and those with [25(OH)D] >= 32.8ng/mL. Chi-square and Fischer exact tests assessed demographic differences.

Results: 36 participants in this study were Caucasian/white (41%), 6 black (7%), and 46 Hispanic (52%). 89% were secretors (n=78). Black and Hispanic mothers were more likely to have 25(OH)D <= 32.7ng/mL than white mothers (p < 0.001). Hispanic mothers were more likely to be secretors than black and white mothers (p=0.006). Among secretors, Lacto-N-fucopentaose II (LNFP II), Lacto-N-hexose (LNH), and Fucosyldisialyllacto-N-hexaose I (FDSLNH) were positively correlated with vitD at v1 (r=0.27, 0.23, 0.24; p=0.02, 0.04, 0.03 respectively). FDSLNH remained positively associated with vitD at v4 in the secretor group (r=0.24, p=0.03). Among non-secretors, 6’-sialylactose (6’SL) was negatively correlated with vitD at v4 (r=-0.064, p=0.05). As expected, several HMOs differed between secretor groups (p < 0.05).

Conclusion(s): HMO content and vitD status were significantly associated during the first 4 months of breastfeeding in secretor and non-secretor groups. These findings suggest possible environmental and/or dietary influence on HMO profile and possible effects on infant gut development and immunity.