Dissertação de Mestrado Nutrição Humana e Metabolismo 2023 Faculdade de Ciências Médicas, Universidade NOVA de Lisboa

Background: Infantile colic is one of the main causes of discomfort and suffering for an infant, as well as concern and psychological, emotional, and physical strain for the parents. For this reason, infantile colic is a field of clinical research both in terms of etiology and treatment. Some studies suggest that a large ratio of Bifidobacterium and Lactobacillus in the intestinal microbiota of infants protects against colic and agitation. Other studies also point to fennel-based teas having a positive impact on improving symptoms of colic in infants. Objective: To assess the possible changes to the microbiota of the breast milk and of the feces of infants with or under five months old breastfed after the ingestion of a fennel-based tea by the mothers. To isolate and identify bacteria with a potential probiotic effect from the breast milk and feces of the infants. Design: This is a clinical study that includes newborn infants under five months old with symptoms of colic. The intervention involves the ingestion of 1 liter of fennel tea by the mothers throughout the day, over a period of 7 days. It was requested that the mothers collect a sample of their own breast milk and of their infants’ feces. The samples were collected at the beginning and end of the intervention. These were used to identify the bacterial community with high throughput sequencing and to isolate the bacteria with a probiotic aspect. Results: 13 samples of feces and 5 samples of breast milk were examined at the level of the microbiota. Several species that belong to the genus Bifidobacterium were detected in the samples of feces. The number of ASVs in the samples of feces rose significantly (P < 0.05) after the intervention. There was also a significant rise (P < 0.05) of the ASVs belonging to the phylum Firmicutes in the samples of the feces after the intervention, excluding one sample that was drastically different to the rest. Conclusion: This study indicates that the bioactive compounds in fennel have a prebiotic effect in infants breastfed by mothers who consume fennel tea by selectively stimulating the rise of the number of beneficial bacteria in the intestinal microbiota, namely some genera belonging to the phylum Firmicutes and bacteria of the genus Bifidobacterium, thus reducing the symptoms of infantile colic. This study represents an inspiration for possible future studies who seek to better understand the effects of fennel tea in the decrease of symptoms of colic in infants