Cognition in First Graders in Ivory Coast: Effects of a Probiotic Food Supplement

• In Event: Enhance cognitive functions across development: factors, strategies or interventions

Abstract

Despite a growing body of work documenting links between probiotics, cognition, and health in adults, the question of whether probiotics influence child cognitive development is unexplored to date. However, it is reasonable to hypothesize a link either through direct effects via the gut-brain-axis or mediated effects via health or mood. This study was a semi-randomized controlled trial to examine whether consumption of a probiotic food supplement (dêguê, a West-African yogurt with millet) affected children’s cognitive capacities. We hypothesized that the probiotic consumption would positively affect children’s cognition.

Participants were 251 four- to seven-year-old children recruited from two schools in a low-income area of Abidjan, Ivory Coast. Cognitive tests were completed after enrollment (T1), and approximately five months later (T2). Demographics were collected through a caregiver interview. After baseline testing, children from one school were randomly assigned to receive probiotic (n = 74) or control dêguê (n = 79) each day they were in school for 18 weeks (excepting 18 days due to holidays, etc.). Probiotic dêguê was fermented using Lactobacillus Rhamnosus GG (a known and studied probiotic) and Streptococcus Thermophilus bacterium; control dêguê with Streptococcus Thermophilus alone. Children at the other school (N = 98) followed their diets as usual.

Testing, attention and processing speed were assessed with a Cancellation task (e.g., Gauthier et al., 1989). Inhibitory control and cognitive flexibility were assessed using computerized Flanker and Dimensional Change Card Sort tasks, respectively (e.g., Eriksen & Eriksen, 1974; Monsell, 2003), and selective attention was assessed using a Go / no go task (e.g., Riccio et al., 2002). Finally, in T2 only, numerical ability was assessed using a Numeracy screener (Nosworthy et al., 2013). We examined group and exploratory dose response effects. Effects were examined in main analyses with complete case analysis and a series of sensitivity analyses appropriate to each task’s missing data.

Results: Examinations of probiotic effects were equivocal with results discrepant between main and sensitivity analyses. Briefly: the placebo group had worse scores on a numeracy task than the DAU group, but not in sensitivity analyses. The placebo group had worse scores than average on the Cancellation task and the probiotic group had worse Go / no go scores than the placebo and DAU groups, but only in sensitivity analyses. Exploratory analyses indicated that milliliters of dêguê consumed was negatively associated with Go / no-go scores in the probiotic group only when covariates were included; sensitivity analyses indicated that the probiotic group had lower scores regardless of milliliters consumed. Finally, there was some evidence that regularity of consumption was positively associated with Cancellation scores, but effects didn’t reach significance in sensitivity analyses. Mean scores for each task are presented in Figure 1.

Findings are discussed in light of administration difficulties resulting from a six-week teacher strike that occurred during the study. Notably, the mean number of days experimental participants consumed dêguê is less than half the days it was offered over a four-month period. Future directions, including continued investigation into the probiotic-cognition link, are suggested.

Authors

• Bonnie Erin Brett, Radboud Universiteit Nijmegen
  Presenting Author

• Carolina de Weerth, Radboud University Medical Center
  Non-Presenting Author