The exact cause of irritable bowel syndrome (IBS) hasn’t been discovered yet, so we can say that IBS isn’t fully understood. However, there are factors that doctors and studies have determined as main contributors and causes of irritable bowel syndrome. These factors are:
○ Bacterial factors
- The most typical cause of IBS is an infection, so active bacterial or viral infection may severely affect the gut causing irritation and inflammation as in gastroenteritis.
- Modulation of the healthy bacteria living in the gut is considered a highly likely cause of irritable bowel syndrome as experts found that the intestinal bacteria of patients suffering from irritable bowel syndrome is different from the bacteria of healthy people.
- Overgrowth in intestinal bacteria has a noticeable effect on the intestinal homeostasis (internal balance and stability) as it produces gases and toxins, causing bloating, which may lead to IBS.
○ Hormonal factors
It is well known that women suffering from Irritable bowel Syndrome are more than men with a ratio 2:1, and its symptoms strongly appear as menstruation approaches. Thus, it is proposed that changes in hormones may cause IBS.
○ Nervous factors
- Any slight damage to the enteric nervous system controlling the motility and secretion of the small and large intestine during surgical operation predispose the patient to suffer from irritable bowel syndrome.
- Abnormal reflexes in the brain-gut axis due to the presence of food in the gut may cause exaggerated or weak response, triggering similar symptoms to those of irritable bowel syndrome.
○ Dietary factors
- The prevalent dependence on fast food containing too much sauce, spices, salt, and chill is considered the most frequent cause of irritable bowel syndrome, contributing to form inflammatory tissues in the intestines which will lead to most IBS symptoms such as diarrhea alternated with rough constipation and bloating.
- Specific food causing allergic reflex is a common known cause of irritable bowel syndrome. This one isn’t fully understood, and there are no listed food allergies so far, so keep in mind that any kind of food could cause allergy to anyone at any stage of life. Allergic reflex may cause similar manifestations to those of IBS.
- Sensitivity to fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) such as those found in apples, apricots and peaches may contribute to causing IBS, as it promotes the sensation of thirst, leads to drinking more water, and this causes fermentation in the large and small intestine forming irritable tissue in the gut and subsequently cause irritable bowel syndrome.
○ Hereditary factors
It is found that people with a family history of irritable bowel syndrome are more likely to suffer from IBS than those with a clear account. According to the previous observation theories, there are prevalent claims that irritable bowel syndrome is mainly passed down genetically and there’s a genetic link playing a significant role in its onset, but none of these claims are well proved.
○ Psychosocial factors
Doctors found that people who suffer from stress, depression, anxiety, mood swings or any overwhelming social emotions could be predisposed to irritable bowel syndrome, and they are more likely to suffer from its symptoms while facing social distress, as in near project deadlines and college exams. Another forgettable minor cause of irritable bowel syndrome is the quality of life because people with a low life quality are more likely to get IBS than those with reasonably better life quality. Statics also shows that 35% of people living in unhealthy environments suffer from irritable bowel syndrome in an early stage of life or young adulthood.
○ Enzymatic factors
There is no doubt that enzymes are indispensable throughout the digestion process, so any deficiency in digesting enzymes whether they are produced in the pancreas, the stomach or intestines will lead to mal-digestion and mal-absorption as food isn’t broken down properly. Accumulation of undigested food in the gut cause irritation of the surrounding tissue which may cause irritable bowel syndrome.
○ Immunity factors
Presence of many immune cells in the intestinal tissues or exaggerated immunologic reflex to intestinal infection could effectively cause similar symptoms to those of irritable bowel syndrome which usually include colic pain and chronic fatigue.
○ Other factors
- It is believed that certain sorts of drugs and medications could possibly cause irritable bowel syndrome such as iron supplements. High blood pressure drugs, as well as group of antacids, were recorded as a cause of IBS.
- Some diseases are frequently associated with the same symptoms with irritable bowel Syndrome such as Crohn’s disease and ulcerative colitis, and their link with IBS is researchable.
*Finally, many doctors consider irritable bowel syndrome an idiopathic (for unknown reason) disease, so we must take into consideration this unneglectable point and understand that it may be a functional or physiological disorder.