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

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.

Nutritional influences on cognitive function: mechanisms of susceptibility.

The impact of nutritional variation, within populations not overtly malnourished, on cognitive function and arousal is considered. The emphasis is on susceptibility to acute effects of meals and glucose loads, and chronic effects of dieting, on mental performance, and effects of cholesterol and vitamin levels on cognitive impairment. New developments in understanding dietary influences on neurohormonal systems, and their implications for cognition and affect, allow reinterpretation of both earlier and recent findings. Evidence for a detrimental effect of omitting a meal on cognitive performance remains equivocal: from the outset, idiosyncrasy has prevailed. Yet, for young and nutritionally vulnerable children, breakfast is more likely to benefit than hinder performance. For nutrient composition, despite inconsistencies, some cautious predictions can be made. Acutely, carbohydrate-rich-protein-poor meals can be sedating and anxiolytic; by comparison, protein-rich meals may be arousing, improving reaction time but also increasing unfocused vigilance. Fat-rich meals can lead to a decline in alertness, especially where they differ from habitual fat intake. These acute effects may vary with time of day and nutritional status. Chronically, protein-rich diets have been associated with decreased positive and increased negative affect relative to carbohydrate-rich diets. Probable mechanisms include diet-induced changes in monoamine, especially serotoninergic neurotransmitter activity, and functioning of the hypothalamic pituitary adrenal axis. Effects are interpreted in the context of individual traits and susceptibility to challenging, even stressful, tests of performance. Preoccupation with dieting may impair cognition by interfering with working memory capacity, independently of nutritional status. The change in cognitive performance after administration of glucose, and other foods, may depend on the level of sympathetic activation, glucocorticoid secretion, and pancreatic beta-cell function, rather than simple fuelling of neural activity. Thus, outcomes can be predicted by vulnerability in coping with stressful challenges, interacting with nutritional history and neuroendocrine status. Functioning of such systems may be susceptible to dietary influences on neural membrane fluidity, and vitamin-dependent cerebrovascular health, with cognitive vulnerability increasing with age.

Factor-analytic structure of food preferences in four-year-old children in the UK.

Studying the correlative structure of young children's food preferences may help us to understand the influences on the development of eating habits. We investigated patterns of food preferences in 214 same-sex twin pairs aged 4 to 5 years. Mothers completed a questionnaire of their children's likes and dislikes for 94 common foods. The proportion of children having tried each food, and their liking for it, were examined. These two measures were strongly positively correlated (r=0.61). Principal components analysis was used to examine the inter-relationships among preferences for 76 foods that had been tried by at least 75% of the children. Four factors emerged, interpreted from food factor loadings as "Vegetables", "Desserts", "Meat and Fish", and "Fruit", explaining 24% of the variance. Thus, children tended consistently to like or dislike foods within each of these factor categories, independently of patterns of liking in the other factors. Factor loadings were unrelated to average liking for or likelihood of exposure to these foods. The distribution of factor loadings refutes the common assumption that simple sensory properties such as sweetness, saltiness or fattiness predict food preferences. Instead, a preference structure may develop for more complex multimodal sensory syntheses, which could have both biological and learnt bases. Future work comparing the food preference structure of mono- and dizygotic twins should help determine the relative contribution of genetic and environmental influences.