Causes

Causes of irritable bowel syndrome (IBS)

The exact cause of irritable bowel syndrome (IBS) is unknown, but most experts agree it is related to an increased sensitivity of the entire gut.

This can be caused by:

Ø  A change in your body's ability to move food through your digestive system

Ø  Becoming more sensitive to pain from your gut

Ø  Psychological factors

Ø  An episode of food poisoning

Experts are not sure what IBS causes are. It is thought the following interrelated factors are probably involved:

ü  Dietary factors (which we don't know about)

ü  Environmental factors (which we don't know about)

ü  Genetic factors (which we don't know about)

ü  The central nervous system does not control the digestive system properly

ü  The digestive organs are excessively sensitive to pain

ü  The response to infection is unusual

ü  The way muscles move food through the digestive tract is abnormal

ü  There is something wrong with the immune system (possible related to response to infection)

Mental and emotional state - evidence suggests that psychological and emotional factors probably play a big role in IBS. This does not mean the condition is all in the mind, but rather that changes in an individual's emotional/mental state, such as depression, stress or anxiety may cause flare-up symptoms to occur. People who have had a traumatic experience have a higher risk of developing IBS.

Triggers - some people with IBS react strongly to stimuli that would not affect people without IBS. Examples may include:

¬  Food - a significant number of individuals with IBS find that their symptoms get worse after they have eaten certain foods, such as chocolate, milk or alcohol, which give them either constipation or diarrhea. Bloating and/or discomfort may be caused by some fruits and vegetables, as well as fizzy drinks. Experts are not sure what role food allergy or intolerance play (if any) in IBS.

Cramping or bloating after eating dairy products, sugar-free gum, some candies, or products with caffeine in them may be due to lactose (sugar), sorbitol or caffeine intolerance, and not IBS.

¬  Hormones - a considerable number of women with IBS find that their symptoms are worse around the time of menses (menstrual periods).

¬  Infections - gastroenteritis can trigger IBS.

The causes of IBS are not well understood. Researchers believe a combination of physical and mental health problems can lead to IBS.

Brain-Gut Signal Problems

¬  Signals between the brain and nerves of the small and large intestines, also called the gut, control how the intestines work. Problems with brain-gut signals may cause IBS symptoms, such as changes in bowel habits and pain or discomfort.

GI Motor Problems

¬  Normal motility, or movement, may not be present in the colon of a person who has IBS. Slow motility can lead to constipation and fast motility can lead to diarrhea. Spasms, or sudden, strong muscle contractions that come and go, can cause abdominal pain. Some people with IBS also experience hyper reactivity—a dramatic increase in bowel contractions in response to stress or eating.

Hypersensitivity

¬  People with IBS have a lower pain threshold for bowel stretching caused by gas or stool compared with people who do not have IBS. The brain may process pain signals from the bowel differently in people with IBS.

Mental Health Problems

¬  Mental health, or psychological, problems such as panic disorder, anxiety, depression, and post-traumatic stress disorder are common in people with IBS. The link between these disorders and development of IBS is unclear. GI disorders, including IBS, are often found in people who have reported past physical or sexual abuse. Researchers believe people who have been abused tend to express psychological stress through physical symptoms.

Bacterial Gastroenteritis

¬  Some people who have bacterial gastroenteritis—an infection or irritation of the stomach and intestines caused by bacteria—develop IBS. Researchers do not know why gastroenteritis leads to IBS in some people and not others, though abnormalities of the GI tract lining and psychological problems may be factors.

Small Intestinal Bacterial Overgrowth

¬  Normally, few bacteria live in the small intestine. Small intestinal bacterial overgrowth is an increase in the number or a change in the type of bacteria in the small intestine. These bacteria can produce extra gas and may also cause diarrhea and weight loss. Some researchers believe that small intestinal bacterial overgrowth may lead to IBS, and some studies have shown antibiotics to be effective in treating IBS. However, more research is needed to show a link between small intestinal bacterial overgrowth and IBS.

Body Chemicals

¬  People with IBS have altered levels of neurotransmitters—chemicals in the body that transmit nerve signals—and GI hormones, though the role these chemicals play in developing IBS is unclear. Younger women with IBS often have more symptoms during their menstrual periods. Post-menopausal women have fewer symptoms compared with women who are still menstruating. These findings suggest that reproductive hormones can worsen IBS problems.

Genetics

¬  Whether IBS has a genetic cause, meaning it runs in families, is unclear. Studies have shown IBS is more common in people with family members who have a history of GI problems. However, the cause could be environmental or the result of heightened awareness of GI symptoms.

Food Sensitivity

¬  Many people with IBS report that symptoms are triggered by foods rich in carbohydrates, spicy or fatty foods, coffee, and alcohol. However, people with food sensitivity typically do not have clinical signs of food allergy. Researchers have proposed that symptoms may result from poor absorption of sugars or bile acids, which help break down fats and get rid of wastes in the body.

==--==