FGIDs are very frequent. Indeed, for many of us, it’s one of the most common diagnoses of the patients that we see is that they suffer from FGIDs. I will focus on regurgitation, infant colic and constipation because they are definitely the most frequent. 

FGIDs are defined by the Rome criteria, which were established by working groups of the Rome Foundation. These criteria are symptom based and based on literature and consensus meetings. The name “Rome” comes from the place where the first meetings took place. 

The pathophysiology of f FGID is common. This condition could be considered a disease because more than one organ is involved. I like to define FGID as a lack of communication among the organs. Maybe they talk different languages and there is still no interpreter to translate for the different organs involved in the patophisiolog.

For the functional abdominal pain disorders or pain-related FGID, we have four categories in the Rome IV criteria: functional dyspepsia, irritable bowel syndrome (IBS), abdominal migraine and functional abdominal pain, now characterized as “not otherwise specified.” Here I would try to focus more on the children who were older than infant age, meaning toddlers and older children.

Functional gastrointestinal disorders (FGID) are very common during infancy, leading to frequent medical consultations. Parents are often worried about the health of their child and they want appropriate medical management. For the most of the times, it is not so easy and the family’s quality of life could be impaired. 

Infant microbiota dynamically develops during the first weeks and months of life. Bacterial diversity generally increases with age, accompanied by changes in microbiota composition. Microbiota consists of numerous taxa; this complexity can be described as “microbiota types” where samples with similar microbiota composition are clustered using complex algorithms.

Necrotising enterocolitis (NEC) is an inflammation and ischemia of intestinal mucosa. 10% of neonates < 1500 gram develop NEC and the mortality is still very high: 15–30%. There are many complications, e.g. short bowel syndrome, stenosis and developmental delay.

The immune system is a system of cells and tissues that protects us against invading pathogens. It must learn how to provide tolerance to “non-threats” such as food components, commensal microbiota and to the organism itself. So it must actually learn how to distinguish “harmless” from “dangerous” – and this is an active process.

The last 30 years have seen a dramatic increase in survival of infants born preterm. The reasons for these improvements are complex, but there is strong reason to believe that improved attention to nutritional management has had a key impact on improving short- and long-term outcomes.

The brain is the fastest-growing organ in young children. Furthermore, the brain develops very rapidly during the latter part of gestation and the first 2–3 years of life, and adequate nutrition is essential for the processes of neural proliferation, neural migration, axonal and dendrite growth and arborization, synapse formation and myelination.