Description
Sometimes food is eaten that contains food-poisoning organisms or causes irritation to the stomach. If this happens, the best course of action is to remove it from the stomach by vomitting. The vomit control centre stimulates the the diaphragm and muscles in the abdomen to contract and push the stomach contents back out through the mouth.
 
The medical term for vomitting is emesis. There are many other slang terms for 'being sick' or 'throwing up'.
 

Causes
Vomitting is desirable if the food in the stomach is likely to cause food poisoning or damage the lining of the digestive system. In these cases it is better that the stomach contents are prevented from passing down into the small intestines.
 
Sometimes the cause is not due to bad food. For example, motion sickness, noxious smells and some cancer therapies may also cause vomitting. In circumstances like these, it is beneficial to give a medicine to stop the vomitting.
 
Bulimia nervosa is an eating disorder were the sufferer makes themselves sick after eating a meal so that they do not put on weight. This causes damage to the body in many ways. Stomach acids eat away at the teeth and damage the oesophagus in addition to the loss of weight due to a lack of nutrition.
 

Treatments
Anti-emetic medicines can be given to stop a person vomitting when the cause is not due to food poisoning. They effect the region of the brain that controls vomitting and inhibits its action. Many motion sickness remedies work in this way and are taken a short time before the start of the journey.
 
Bulimia nervosa may have many causes and often relates to the person's psychological state of mind. A range of treatments and counselling may be required to treat the disorder.

Description
The stomach makes hydrochloric acid which helps digestion. Sometimes people get a burning pain in the chest after eating. It’s called heartburn. This happens when acid moves from the stomach up into the oesophagus. It may happen because the top sphincter isn’t working properly and the acid leaks out. Or it might be caused by too much pressure on the stomach if a person is pregnant or overweight. Antacid medicines give temporary help by neutralising the acid.

Causes
Excess acid is produced in the stomach. This can be due to nervous factors such as stress. It is also made worse if fatty foods are eaten. These stay in the stomach for longer periods of time and this results in an increase in acid production.
 

Treatments
Medicines called antacids contain alkalis which neutralise the stomach acid. Other medicines can be given that block, or reduce, the production of acid. Changes in diet to avoid fatty foods will also have a beneficial effect.
 

Description
Ulcers are most often found in the stomach or duodenum and are areas where the digestive juices have caused damage to the intestine wall. In severe cases, a perforated ulcer causes bleeding and can allow infections to get into the abdomen.
 
Ulcers can happen to both men and women of any age. Women generally get stomach ulcers while men are more likely to develop duodenal ulcers. Sufferers have pains in the abdomen, often following a meal, which in some cases can be very severe. Ulcers are generally confirmed by viewing the affected area using an endoscope which is a camera on the end of a flexible tube that is passed down the oesophagus and into the stomach.
 

Causes
Traditionally, ulcers were thought to be caused by excessive stomach acids that attacked the lining of the stomach or duodenum. High acid secretion in the stomach can be triggered by high fat diets, smoking, alcohol, stress and some painkilling medicines.
 
Research has now shown that the majority of ulcers are actually caused by a bacteria capable of living in the mucus that normally protects the stomach wall. Helicobacter pylori causes inflammation in the wall of the stomach or duodenum and reduces the protective nature of the mucus. Without this protection, the stomach acids and digestive juices attack the wall of the stomach or duodenum.
 

Treatments
There are several types of treatments depending on the severity of the ulcer.
 
The symptoms of an ulcer may be reduced by a change in diet to reduce fat intake, stop smoking and drinking alcohol. Traditionally, an antacid medicine would also be prescribed. These contain alkali compounds such as sodium bicarbonate that neutralise the excess acids produced by the stomach wall. This treatment is only effective in mild cases and more modern medicines, called H₂-antagonists, are now used to prevent the production of excessive stomach acid rather than just neutralise it. This treatment is usually combined with a course of antibiotics to kill the Helicobacter pylori and allow the stomach wall to repair itself.

Description
One of the jobs of the large intestine is to remove water from the residue of food. If too little water is removed, the result is diarrhoea or ‘the runs’. Some micro-organisms cause diarrhoea by irritating the gut. One simple treatment is to drink lots of water with certain salts dissolved in it, and stop eating for about 24 hours.
 

Causes
Infections such as dysentery cause the small intestine to become irritated and inflamed. The body reacts to try and expel the infection as quickly as possible and so the faeces are moved quickly through the digestive system. Little water is removed from the faeces which become runny. Diarrhoea can prove to be dangerous in the very young or elderly because it can cause serious dehydration and an imbalance in the body salts.
 

Treatments
The main treatment is to avoid dehydration by drinking plenty of liquids and replacing the lost body salts. In severe cases, this may be done using an intravenous drip. In general, once the infection has been removed from the body the diarrhoea will stop. If required, medicines can be given which reduce the frequency of muscular contraction in the intestine to slow or stop the diarrhoea.

Description
Constipation happens when food is not pushed along the digestive system by the action of peristalsis. It stays in the digestive system for longer than usual and excess water is removed which makes the faeces hard and compacted.
 
Constipation can cause damage to the walls of the large intestine as it strains to push the hard faeces out. Constipation leads to haemorrhoids (piles) and is thought to increase the chance of developing bowel cancer because bacteria act on the faeces to produce toxic waste products.
 

Causes
Fibre in the diet is indigestible. It gives the food bulk, holds it together, and allows the peristalsis to work efficiently. Constipation can be caused by a lack of fibre in the diet because the food is not pushed along the digestive system as smoothly as it should be. The digested food spends an extended time in the large intestine which can make it dry and hard. This means the faeces are difficult to pass out.
 
Other causes of constipation include the side effects of some medicines, a lack of liquid in the diet or ignoring the need to pass faeces. Sometimes constipation can be a symptom of a more serious bowel condition and if constipation persists it should be investigated by a Doctor.
 

Treatments
Laxatives can be given to increase the intensity of the muscular contractions and push the food along the digestive system or increase the retention of water in the faeces to make them softer. Laxatives should not be used over prolonged periods of time as the underlying cause of the constipation must be treated.
 
The best treatment is to prevent constipation by eating sufficient fibre in the diet. Good sources of fibre include vegetables and whole wheat cereals. Current recommendations state that at least five portions (or 400g) of fruit and vegetables should be eaten every day as part of a balanced diet.

Description
Once nutrients have been digested, they must be absorbed into the bloodstream. This happens in the small intestine. Many conditions can interfere with this process and cause some severe problems because the nutrients in the diet are not getting into the body. People suffering from poor absorption may have symptoms of abdominal pain, bloating, dehydration, fatigue and weight loss in addition to the problems caused by the lack of a specific nutrient. For example, anaemia can be caused because, even though there is enough iron in the diet, it is not absorbed and so not enough red blood cells can be made.
 

Causes
There are many possible causes of poor nutrient absorption. Disease of the pancreas and cystic fibrosis can mean that foods are not properly digested because insufficient enzymes are added to the food. Parasitic infections, like worms, can absorb nutrients from the food and so prevent them from being taken in by the body. Surgery is often used to treat cancers and in this case a section of the intestine is removed and this reduces its ability to absorb nutrients.
 

Treatments
The treatment will be tailored according to the underlying cause of the poor absorption. If it is due to a lack of pancreatic enzymes, medications can be given that contain the missing enzymes. These are contained in capsules that pass through the stomach and then release their enzymes in the small intestine. Nutrient supplements can be added to the diet to and in severe cases, nutrients may be given by an intravenous drip.
 
Disorders such as celiac disease may cause damage to the villi of the small intestine. Sufferers may be prescribed medicines to reduce the inflammation of the small intestine in addition to close control of their diet.

Description
Gluten is a protein that is found in cereals such as wheat, rye, barley, and oats. Coeliac disease is an inherited disorder that causes the immune system to react to gluten in the diet and cause an inflammation in the lining of the small intestine that damages the villi.
 
There are not one set of specific symptoms but sufferers tend to be prone to anaemia, weight loss, bone pain and skin problems because of the poor absorption of nutrients.
 

Causes
Coeliac disease is a genetic disorder but it also depends on the person's exposure to gluten in the diet. It is not caused by a single defective gene but a combination of genes that normally work together.
 
The prevalence of the disease varies and can be as high as 1 sufferer in every 300 people in some parts of Europe. A recent study suggested that 1 in 250 people in the United States suffer from some form of coeliac disease, although not all have been diagnosed by their doctor.
 

Treatments
Coeliac disease sufferers must not eat gluten as even small amounts in the diet can cause problems. Cereals must be avoided but it can prove difficult to remove all gluten from the diet as it is often added to processed foods such as soups, sauces and even ice cream.
 
Extra vitamin and mineral supplements may need to be taken to overcome their poor absorption in the small intestine. In extremely severe cases, young children suffering from celiac disease may need to be given intravenous nutrition until the disorder is controlled.

Description
Sufferers from lactose intolerance cannot digest the sugar lactose that is found in milk and dairy products. It happens because the small intestine does not produce enough of the carbohydrase enzyme called lactase.
 
Lactose intolerance is not found in small babies, but develops after the age of around five. After drinking milk or eating dairy products, undigested lactose can be fermented by bacteria in the intestines and cause symptoms such as abdominal pain, diarrhoea, wind and a bloated feeling. If untreated, long-term effects can include weight loss and slow growth.
 

Causes
Lactose intolerance is caused when the small intestine does not produce enough of the enzyme lactase. This normally breaks down the milk-sugar lactose into simple sugars that can be absorbed. The disorder is caused when a recessive gene is inherited from both parents.
 
Lactose intolerance is a good example of variation and seems to be connected to the genetic make-up of the sufferer. Over the entire population of the world, 75% of adults show some degree of lactose intolerance. However, when different ethnic groups are studied the incidence varies greatly. Less than 20% of Northern European origin are affected whilst 90-100% of Chinese descent are intolerant.
 

Treatments
Removing milk and dairy products from the diet will help to treat the symptoms although lactose may be found in other processed foods. Yoghurts and cheese may sometimes be tolerated because they are made from fermented milk that contains less lactose.
 
Completely removing milk from the diet can lead to a lack of Calcium and so a mineral supplement is often taken. Medicines can be given that contain the lactase enzyme in a capsule that is not digested in the stomach and releases the enzyme once it reaches the small intestine.

Description
Parasitic worms can be caught by eating infected food that has not been cooked properly. Tapeworms are long, flat and attach themselves to the inside of the small intestine before absorbing nutrients from the semi-digested food. They can grow to over 4 metres in length and deposit eggs in the faeces which then pass on the infection. Roundworms are generally smaller and do not attach to the wall of the intestine but swim in the digested food absorbing nutrients.
 
An infected person may not have any severe symptoms. There may be some pain in the abdomen, diarrhoea, constipation or weight loss but often the only sign of infection is the presence of eggs in the clothing, bedding, or faeces.
 

Causes
Hygiene regulations mean that foods are checked to make sure they do not contain worm-infections and proper cooking means that worms are destroyed. Worms can however be passed from pets and other animals in contaminated faeces.
 
An example of one parasite that can infect humans is the beef tapeworm. Cattle pick up the tapeworm when they eat grass which has had infected faeces spread on it. The worms spend part of their life growing in the cow and form cysts in the muscle tissue. If the cysts are eaten, they pass the infection into the digestive system of the human where the worm continues its life cycle.
 

Treatments
Tapeworms are treated with medicines that stop the process of respiration in the head of the tapeworm. This causes it to detach from the intestine wall and it can be passed out in the faeces. A laxative is also given to make certain that all of the worm is expelled.
 
Roundworms are treated with medicines that prevent them from maintaining their movement which keeps them in the digestive system so that they are passed out in the faeces.

Description
Amoebic dysentery is a parasitic infection that occurs mostly in tropical climates. It causes severe diarrhoea containing blood, mucus and live parasites which can transfer the infection if faeces contaminate bathing or drinking water.
 
Dysentery causes the death of many children in developing worlds. The severe diarrhoea causes dehydration and a loss of essential body salts which can prove fatal. Some forms of amoeba are able to move through the intestine wall and infect the bloodstream before spreading to cause damage in the liver, lungs and brain.
 

Causes
Amoeba are single celled protozoa and amoebic dysentery is a parasitic infection. The parasitic amoeba are passed on when water supplies, used for cooking or drinking, are shared with water for bathing and sewage disposal.

Treatments
Preventing contamination of drinking water with human faeces will help to stop infection and re-infection.
 
Once infected, sufferers should be given drinks containing glucose and salt to replace the lost salts and water. Boiling drinking water for 10-15 minutes will also kill the parasite but unfortunately, these simple treatments are often not available.
 
Medicines can be prescribed that kill the parasites but unless the underlying cause of contaminated drinking water is treated then reinfection is likely to occur.