Digestive problems can range from temporary discomfort after eating to life-long persistent disorders. In most cases, the treatment is simply to avoid the foods that cause the symptoms.
Many adults lack the enzyme lactase, which is needed to break down lactose, the sugar found in milk. All healthy babies have it, but most of us stop producing this enzyme after weaning. Only about 35 per cent of the world’s population have acquired a mutation that allows them to produce lactase into adulthood.
Who isn’t lactose intolerant? – Countries that have a long history of diary farming tend to have populations that have adapted o drinking milk into adulthood. Most of these countries are in Europe.
- Lactose in small intestine – When the cells that line the walls of the small intestine encounter the sugar lactose, they start to produce the digestive enzyme lactase.
- Lactose digested by lactase – Lactase breaks lactose into two smaller sugars – galactose and glucose.
- Galactose and glucose absorbed – These two smaller sugars are then absorbed into the bloodstream by the small intestine.
- Undigested lactose – If lactase isn’t present, then lactose can’t be absorbed and instead passes into the large intestine.
- Bacterial fermentation – Bacteria living in the large intestine ferment the lactose, producing gas and acids in the process.
- Disruption in the bowel – The gas produced by fermentation causes bloating and discomfort, while the acids draw water into the bowel, leading to diarrhoea.
Bringing it up – One way the body avoids digestive problems is by vomiting. When we eat something rotten or poisonous, the stomach, the diaphragm, and the abdominal muscles all contract, forcing the food back up through the oesophagus and out through the mouth.
Irritable bowel syndrome
IBS is a long-term condition that can cause stomach cramps, bloating, diarrhoea, and constipation. It is poorly understood, but seems to be triggered by stress, lifestyle, and certain types of food.
- Bacterial fermentation – Carbohydrates that are poorly absorbed may increase the amount of water in the intestinal tract. Once in the large intestine, these carbohydrates are fermented by bacteria, producing acids and gas.
- Bowel spasms – IBS causes bowel spasms, which can block the waste and gas from passing through. Alternatively, it can cause the waste to move too quickly, preventing water reabsorption and causing diarrhoea.
Many people experience abdominal pain, fatigue, headaches and even numbness of the limbs when they eat gluten – a protein found in grains such as wheat, barley and rye. These symptoms are indicators of various gluten-related disorders, ranging from gluten sensitivity to coeliac disease.
Lethargy, mental fatigue, cramps and diarrhoea are all symptoms of gluten sensitivity, which is only cured by avoiding all gluten products – including rye bread, beer and pasta. Gluten sensitivity does not damage the intestines like coeliac disease does.
Coeliac disease is a serious genetic disorder that causes the body’s immune system to attack itself when it encounters gluten. This immune response causes damage to the lining of the small intestine and so inhibits the absorption of nutrients. Left unchecked, it can totally destroy the small intestine’s little finger-like projections, or villi.