A prebiotic intervention study in children with autism spectrum disorders (ASDs)

Abstract

Background: Different dietary approaches, such as gluten and casein free diets, or the use of probiotics and prebiotics have been suggested in autistic spectrum disorders in order to reduce gastrointestinal (GI) disturbances. GI symptoms are of particular interest in this population due to prevalence and correlation with the severity of behavioural traits. Nowadays, there is lack of strong evidence about the effect of dietary interventions on these problems, particularly prebiotics. Therefore, we assessed the impact of exclusion diets and a 6-week Bimuno® galactooligosaccharide (B-GOS®) prebiotic intervention in 30 autistic children.

Results: The results showed that children on exclusion diets reported significantly lower scores of abdominal pain and bowel movement, as well as lower abundance of Bifidobacterium spp. and Veillonellaceae family, but higher presence of Faecalibacterium prausnitzii and Bacteroides spp. In addition, significant correlations were found between bacterial populations and faecal amino acids in this group, compared to children following an unrestricted diet. Following B-GOS® intervention, we observed improvements in anti-social behaviour, significant increase of Lachnospiraceae family, and significant changes in faecal and urine metabolites.

Conclusions: To our knowledge, this is the first study where the effect of exclusion diets and prebiotics has been evaluated in autism, showing potential beneficial effects. A combined dietary approach resulted in significant changes in gut microbiota composition and metabolism suggesting that multiple interventions might be more relevant for the improvement of these aspects as well as psychological traits.

Trial registration: NCT02720900 ; registered in November 2015.

Keywords: 1H-NMR; Autism; GOS; Gut symptoms; Microbiota; Prebiotics; Sequencing.

Fig. 1

GI symptom assessment during 3 weeks baseline data collection. S exclusion diets; N unrestricted diet; *P < 0.05; ***P < 0.001

Fig. 2

a ATEC questionnaire. Results showed consistent reduction over time in anti-sociability score in children on the combination of the exclusion diet and B-GOS intervention, with the most apparent difference occurring at follow-up (time × diet × treatment interaction, p = 0.05; adjusted for age). Placebo:Maltodextrin. b AQ questionnaire. After intervention and including follow-up, social skills were improved (i.e. scores were lower) by B-GOS treatment in children on the exclusion diet only (diet × treatment interaction, P < 0.05). Results were reported as estimated marginal means ± standard error (SE). NB, post-hoc comparisons are not valid where covariates are included

Fig. 3

a PCA plot showing differences in microbial genera based on diet as determined by RDA analysis. b PCA plot displaying differences in microbial genera after B-GOS treatment in un-restricted diet group as determined by RDA analysis. Blue dots: after B-GOS® intervention; pink dots: before B-GOS® intervention. X displays the loading positions of the most discriminative bacterial genera

Fig. 4

Summary of the correlation between bacterial changes and metabolic variation in faecal samples of children following exclusion diet a and those in un-restricted diet b. OUTs: bacterial groups. Arrows: metabolites identified; Squares: bacteria involved in the metabolic pathway. OTU001: Bifidobacterium spp.; OUT002: Bifidobacterium longum; OTU003: Coriobacteriaceae; OTU004: Eggerthella lenta; OTU005: Bacteroides spp.; OTU006: B. fragilis; OTU007: B. ovatus; OTU008: B. uniformis; OTU009: Rikenellaceae spp.; OTU010: Lactococcus spp.; OTU011: Streptococcus arginosus; OTU012: Clostridiales; OUT013: Clostridiaceae; OTU014: Dehalobacterium spp.; OTU015: Roseburia spp., OTU016: F. prausnitzii; OTU017: Coprobacillus spp.; OTU018: Akkermansia muciphila

Fig. 5

Study information. a Flow of participants through the study. b Study design