Gastrointestinal problems are common in infancy, during childhood and in teenagers; many families seeking advice from their GP. Changes in the habits of the gut, whether in appetite, difficulty swallowing, digestion (or indigestion) and elimination or are usually quick to identify. The symptoms however may be vague and difficult to understand their cause. Gastrointestinal infections are common in the early years and infants in particular can become quite unwell and easily dehydrated. Persistent and on-going symptoms eg. reflux, pain and altered bowel movements affect life at home and school, at work and play. Growth faltering can happen in more severe cases and with medical gastrointestinal problems. Whilst eliminating underlying medical causes for those symptoms is important, there are instances when symptoms have no obvious cause. So called functional problems may be addressed by attention to diet. Other gastrointestinal problems with a defined medical cause are treated by diet in eg. in coeliac disease, lactose intolerance or food allergy.
Digestion, absorption and elimination of food
The gastrointestinal system or gut is collectively the body’s largest organ system and is responsible for digestion, absorption and elimination of food and bacterial waste. Children should always be given sufficient time to eat their food without distractions, being encouraged to chew food well to release digestive enzymes, which in turn improves digestion. Hunger and appetite are controlled by internal (digestive hormones) and external influences (eg. cooking smells). Simple as it sounds, the act of chewing food well, signals satisfaction to the brain, which in turn helps control hunger and appetite. Digestion begins in the mouth, with the production of salivary amylase and continues in the stomach and upper intestine, stimulating the production of digestive enzymes and hormones. Much of the nutrient absorption takes place in the small intestine with transport proteins directing the traffic of nutrients via the liver, into the circulating blood stream to muscle, bone, brain and other destinations. The gut illustrates its adaptive qualities by regulating nutrient absorption depending on the body’s needs.
Gut brain axis and the food mood dynamic
The gut makes up a significant part of our immune system with its protective barrier and bacterial colonies (microbiota) unique to each individual. A poorly functioning barrier system makes the gut susceptible to infections; the immune system may also become sensitised by food proteins causing food allergy. More brain receptors are found in the gut than anywhere else in the body, and communicate with the brain and the rest of the body. The gut is responsive not only to nutrient absorption, the passage of bacteria and viruses but to other stimulus like emotions and anxieties. Mood, concentration and wellbeing are all influenced by what and how we eat. Physical symptoms experienced in the gut when responding to emotions or stresses, can of course influence our eating behaviour and choices – both consciously and unconsciously. During puberty and the teenage years, a time linked with increasing pressure, anxiety and depression, emotional issues can present as physical problems and vice versa.