Diet and gut microbiome in early lifea potential pathway for atopic disease development?

Abstract

The rise in immune-mediated illnesses, such as atopic dermatitis, is linked to changes in the infant microbiome, influenced by maternal and infant diets. Through fermentation of dietary fibers, gut microbes produce short-chain fatty acids (SCFAs) like butyrate, which have anti-inflammatory properties and may impact disease development. The aim was to assess maternal and infant diets, their impact on the infant gut microbiome and explore the effect of butyrate on atopic dermatitis development in infancy. The thesis used data from the PreventADALL study, a randomized controlled interventional birth cohort study enrolling 2397 mother-child pairs antenatally in Norway and Sweden between 2014-17. Children randomized to food intervention were introduced to complementary foods from 3 months of age. Gut microbiome and short-chain fatty acids were analysed from fecal samples in the pregnant mother, and at birth, 3-, 6- and 12 months of infant age. Atopic dermatitis was clinically assessed at regular intervals in infancy. Maternal diet in pregnancy showed consumption of red meat, salt, saturated fats alcohol, and coffee higher than national recommendations, and inadequate intake of essential micronutrients (folate, iron, selenium, calcium, vitamin D, iodine). Introducing complementary foods before 6 months did not lead to earlier breast-feeding cessation, and increased diet diversity in infancy. Gut microbiota composition changed from birth to 12 months, and butyrate increased 4-fold from 6 to 12 months. Breastfeeding was associated with bacterial taxonomy at 3, but not 6 and 12 months of age, while the time of complementary food introduction was not associated with microbiota. Bacterial networks Eubacterium rectale and Faecalibacterium prausnitzii were identified as key bacteria responsible for butyrate production in the infant gut, whereas Ruminococcus gnavus and its associated network of bacteria were linked to lower butyrate levels. High butyrate levels in the infant’s gut at 12 months were associated with reduced development of atopic dermatitis. These findings point to the role of early life diet in developing a healthy gut microbiota with implications for immune-mediated disease development.