Sex-Dependent Efficacy of Dietary Fiber in Pediatric Functional Abdominal Pain.

BACKGROUND & AIMS: Functional abdominal pain disorders (FAPDs) are more prevalent in female patients. Dietary fiber may alleviate FAPD symptoms; however, whether this effect is sex dependent remains unclear. We investigated the sex dependency of dietary fiber benefit on abdominal pain in children with FAPDs and explored the potential involvement of the gut microbiome. METHODS: In 2 cross-sectional cohorts of children with FAPDs (n = 209) and healthy control individuals (n = 105), we correlated dietary fiber intake with abdominal pain symptoms after stratifying by sex. We also performed sex-stratified and sex-interaction analyses on data from a double-blind trial in children with irritable bowel syndrome randomized to psyllium fiber (n = 39) or placebo (n = 49) for 6 weeks. Shotgun metagenomics was used to investigate gut microbiome community changes potentially linking dietary fiber intake with abdominal pain. RESULTS: In the cross-sectional cohorts, fiber intake inversely correlated with pain symptoms in boys (pain episodes: r = -0.24, P = .005; pain days: r = -0.24, P = 0.004) but not in girls. Similarly, in the randomized trial, psyllium fiber reduced the number of pain episodes in boys (P = .012) but not in girls. Generalized linear regression models confirmed that boys treated with psyllium fiber had greater reduction in pain episodes than girls (P = .007 for fiber × sex × time interaction). Age, sexual development, irritable bowel syndrome subtype, stool form, and microbiome composition were not significant determinants in the dietary fiber effects on pain reduction. CONCLUSIONS: Dietary fiber preferentially reduces abdominal pain frequency in boys, highlighting the importance of considering sex in future dietary intervention studies for FAPDs. (ClincialTrials.gov, Number NCT00526903).

The relative validity of nutrition assessment methods for estimating infant carotenoid intake differs by assessment tool, nutrient database, and milk carotenoid adjustment method.

Validated carotenoid assessment methods are needed to study infant carotenoid nutrition. This is a secondary analysis of repeated diet assessments of healthy participants collected at 4- (n = 21), 6- (n = 12), and 8- (n = 9) months of age in Houston, TX between April 2019 and June 2020. Intake was assessed with 3 assessment tools, analyzed with 3 nutrient databases, and underwent 3 adjustments to account for milk composition variability. We hypothesized that manual adjustment of milk carotenoid intake based on laboratory measurements would improve the validity of all assessment approaches and that using a database with greater coverage of infant food carotenoid compositions would improve accuracy. Generalized linear mixed models assessed associations between tool, nutrient database, age, and milk carotenoid adjustment variables with carotenoid, energy, fruit, and vegetable intakes. The effect of the number of food diary days on intake estimate precision was evaluated by testing the correlation between intake estimates derived from 1, 3, or 5, vs. 7 days. Visit age influenced energy intake estimates (p = .029), along with assessment tool (p = .020). Estimates of vegetable intake were influenced by tool (p = .009). Combined fruit and vegetable intake differed by nutrient database (p = .007). Carotenoid intake differed by age (p =<.0001), tool (p = .002), and nutrient database (p = .004). A minimum of 3 food diary days strongly correlated (rho = 0.79-1) with reference estimates across ages. Milk carotenoid adjustment was most influential in estimating 4-month olds' carotenoid intake, while nutrient database and tool were important for 6- and 8-month-olds', highlighting the dynamic nature of infant diet assessment validity across feeding stages.