Irritable Bowel Syndrome (IBS) is a chronic disorder which causes disturbances in the functions of your digestive system. IBS affects both women and men, although there are more women sufferers. Between 10-20 percent of the global population suffers from IBS, with 70 percent of sufferers experiencing mild symptoms. IBS can present with constipation and/or diarrhea.
Pathophysiology of Irritable Bowel Syndrome
Although the exact causes of IBS are not known, it results in stronger than normal contractions of the muscles within the digestive system. Normally, these muscles contract and relax in a regular rhythm to move food from your stomach, through your intestines to your rectum. If you suffer from IBS, the stronger-than-normal contractions may force food through your digestive system at a more rapid pace leading to bloating, flatulence and diarrhea. Alternatively, IBS can cause the passage of food through the digestive system to become unusually slow, causing your stools to become dry and harden. This will lead to constipation. Other factors that can play a role in IBS include an imbalance of beneficial intestinal bacteria and abnormal serotonin levels. Serotonin is a neurotransmitter found in enterochromaffin cells of the gut as well as in the brain. One of its functions is to stimulate intestinal secretions. Stress may also be a contributing factor.
Causes of IBS:
Post-infection IBS: In some cases it may develop after an individual has suffered bacterial/viral gastroenteritis. This is often related to the duration of the initial infection. Studies show that gastroenteritis that lasts for more than three weeks can increase the risk of developing IBS by up to 11 times. Though the reasons for this are not exactly known, it is thought that the mechanisms may include:
- Post-infectious inflammation
- Changes in the permeability of the intestine
- Imbalance of the gut’s microflora
Gut sensitivity: A further contributing factor is that during a gastric infection, the immune system becomes sensitive to food and microbes in the gut. It is possible that these reactions continue even when the infection has passed, resulting in IBS.
Food intolerance: Another study revealed that food intolerance may also be a causal factor for IBS. This is because consumption of the offending food causes the release of the pro-inflammatory prostaglandin PGE2 which is found in elevated amount in the stool of patients with IBS.
Inflammation: Inflammation also plays a significant role in IBS. Research shows that low-grade mucosal inflammation is present in the intestinal tract of many IBS sufferers. This inflammatory response can be produced or exacerbated by previous gastric infections, undiagnosed food allergies, and imbalances in gut microflora.
Serotonin: Serotonin plays a major role in GI motility by stimulating contractions of the gut. Enterochromaffin (EC) cells are located in the lining of the digestive tract and play a role in regulating gastrointestinal functions. If too much serotonin is released, this can cause diarrhea, too little will result in constipation.
Autonomic nervous system: In cases of IBS, the autonomic nervous system may be altered, leaving it unable to regulate bowel movements.
Psychiatric disorders: For some time now, a link has been recognized between some psychiatric disorders and IBS. In particular, people suffering from a mood disorders are more likely to develop IBS. Up to 66 percent of IBS sufferers, also have a mood disorder.
Genetics: A recent study revealed that IBS sufferers have a mutation of the SCN5A gene. This mutation disrupts bowel functions.
Diagnosis & Symptoms Irritable Bowel Syndrome
If you think you may be suffering from IBS, you should consult your doctor. There is a specific diagnostic criterion for the disorder. Your physician will be able to make a diagnosis by:
- Assessing your symptoms
- Performing a physical examination
- Performing any necessary tests
Symptoms of IBS include:
- abdominal pain or stomach cramps
- abdominal bloating
- alternating bouts of diarrhea and constipation
- mucus in bowel movements
IBS Risk Factors
You may be more at risk of experiencing IBS if:
- you are younger than 35 years of age
- you are female
- you have a family history of IBS
Treatment of Irritable Bowel Syndrome
The symptoms of IBS can often be alleviated by changing your eating habits and your lifestyle, as well as understanding the condition. Your physician may also prescribe medication if your symptoms are severe.
Soluble fiber helps to maintain a healthy bowel function and will also reduce the risk of colon cancer. Fiber may help those with the constipation subtype of IBS. Soluble fiber is better for people with IBS, as it increases the water-holding capacity of the stool, softening it and making passage easier. This means that because it is not as coarse as insoluble fiber, it may cause less irritation to the GI tract.
Gas Producing Foods
Certain foods cause your digestive system to produce gas more than others. Gas can irritate the gut which is particularly troublesome for those with IBS. Your physician may recommend that you avoid foods that produce gas such as:
- Brussels sprouts
- wheat germ/gluten
Fecal Microbiota Transplant
Fecal microbiotia transplant (FMT) is a procedure in which fecal matter containing probiotics and normal gut microbes is transferred from a healthy individual to the recipient. It has been proven successful for treatment of diarrhea causes by C diff that is refractory to antibiotics. In one study of IBS patients FMT improved the symptoms in individuals with IBS at 3 months post-therapy compared to placebo. However, by 12 months the difference was not sustained. This suggests that dysbiosis or an imbalance of gut flora may contribute to IBS symptoms.
Probiotics for IBS
A probiotic is a beneficial bacterial organism that resides in the intestinal tract. Their function is to limit the growth of undesirable bacteria in the gut that can cause irritation and inflammation. They also produce enzymes that help with nutrient absorption, and to help support the immune system. Live probiotics are found in a few foods such as yogurt, kefir and some soft cheeses. You can, however, enrich your diet and improve gut health with probiotic supplements. Probiotics are helpful for IBS sufferers because they prevent the overgrowth of pro-inflammatory bacteria in the intestine and reduce inflammation and irritation of the gut.
The Functions of Probiotics for IBS
Although IBS is a syndrome with multiple and complex factors, up to 45% of cases are the result of infection or overpopulation of undesirable microflora in the GI tract or an abnormal inflammatory response. Probiotics are beneficial organisms which by competing with the bad microorganisms can eliminate them and reduce the risk of the reoccurring. Many probiotic species also support a healthy immune response.
Strains of Probiotics for IBS
Specific probiotics which have been shown to support digestive health and improve IBS include Lactobacillus plantarum, Lactobacillus acidophilus, Streptococcus thermophilus, Lactobacillus bulgaricus, and Bifidobacterium longum strains.
- Lactobacillus acidophilus: One study showed that H. pylori infection results in intestinal inflammation. This can be reduced by taking acidophilus as it prevents the activation of Smad7 and NFκB; proteins that can cause inflammation. Clinical studies have shown that neo-natal mice which are deficient in the IL-10 gene have an abnormally low level of Lactobacillus bacteria in their colon. This causes an increase in pathogenic bacteria. When Lactobacillus levels were normalized, the pathogenic bacteria was reduced, reducing colitis.
- Lactobacillus gasseri: This probiotic stimulates the production of superoxide dismutase (SOD). SOD is one of the body’s most powerful antioxidants. It helps prevent oxidative stress by defending the body against damaging free radicals.
- boulardii: This strain of probiotic can benefit IBS by reducing inflammatory cytokines TNFα and INFγ.
- S thermophilus and B breve: These forms of lactic acid bacteria have been shown to release certain metabolites which prevent TNF-α - a cell-stimulating protein responsible for inflammation – from passing through the intestinal barrier. This may benefit IBS sufferers by support healthy intestinal health.
- Lactobacillus rhamnosus: When IBS is associated with stress and anxiety, this probiotic strain may be useful because it can reduce stress and anxiety. It can also help rebalance mood.
- Bifidobacteria: IBS may also be related to an imbalance of neurotransmitters, particularly serotonin, which plays a key role in gut motility. Bifidobacteria supplementation has been shown to increase the production of tryptophan, which the body converts to serotonin. Bifidobacteria may also have an anti-depressant effect.
Digestive Enzymes for IBS
Gas and bloating is the result of undigested food getting fermented and producing gas inside the gut. Your body produces several different types of digestive enzymes, each of which helps to break down different types of food such as proteins, carbs, and fats so that they are better absorbed. If you are deficient in a particular enzyme, then that related food type will not get digested completely and will be turned into gas by gut bacteria.
You can take digestive enzymes in the form of a supplement to help you digest foods properly without triggering any IBS symptoms or having to eliminate the food from your diet. Some preliminary studies have found digestive enzymes to be helpful for IBS symptoms but more are required. Examples of digestive enzymes include:
- Lipase: this enzyme breaks down complex fats into smaller fatty acids.
- Amylase: this enzyme breaks down sugars into smaller compounds like glucose and maltose.
- Pepsin: this enzyme breaks down proteins into smaller peptides.
Adequate digestive processes, nutrient metabolism and absorption and elimination of waste products are significantly helped by maintaining a healthy diet and a good exercise program. IBS can occur no matter what your body weight, although some of the symptoms such as constipation, heartburn and bloating are more common in people who are overweight. Regular exercise, particularly aerobic exercise, is great for toning the body and the digestive system and keeping metabolic rate up to par. You can, however, enrich your diet and improve gut health with probiotic supplements. Taking probiotics for IBS can help you by rebalancing the beneficial bacteria in your digestive system, improving your digestive processes and relieving abdominal cramping and bloating.
 Hasler WL, Owyang C. Irritable bowel syndrome. In: Textbook of Gastroenterology, 4th ed, Yamada T (Ed), JB Lippincott, Philadelphia 2003. p.1817.