Irritable Bowel Syndrome
Irritable bowel syndrome is a disorder
characterized most commonly by cramping, abdominal pain,
bloating, constipation, and diarrhea. IBS causes a great deal of
discomfort and distress, but it does not permanently harm the
intestines and does not lead to a serious disease, such as
cancer. Most people can control their symptoms with diet, stress
management, and prescribed medications. For some people,
however, IBS can be disabling. They may be unable to work,
attend social events, or even travel short distances.
As many as 20 percent of the adult
population, or one in five Americans, have symptoms of IBS,
making it one of the most common disorders diagnosed by doctors.
It occurs more often in women than in men, and it begins before
the age of 35 in about 50 percent of people.
Researchers have yet to discover any specific
cause for IBS. One theory is that people who suffer from IBS
have a colon that is particularly sensitive and reactive to
certain foods and stress. The immune system, which fights
infection, may also be involved.
Normal motility, or movement, may not be
present in the colon of a person who has IBS. It can be
spasmodic or can even stop working temporarily. Spasms are
sudden strong muscle contractions that come and go.
The lining of the colon called the
epithelium, which is affected by the immune and nervous
systems, regulates the flow of fluids in and out of the
colon. In IBS, the epithelium appears to work properly.
However, when the contents inside the colon move too
quickly, the colon loses its ability to absorb fluids. The
result is too much fluid in the stool. In other people, the
movement inside the colon is too slow, which causes extra
fluid to be absorbed. As a result, a person develops
A person’s colon may respond strongly
to stimuli such as certain foods or stress that would not
bother most people.
Recent research has reported that
serotonin is linked with normal gastrointestinal (GI)
functioning. Serotonin is a neurotransmitter, or chemical,
that delivers messages from one part of the body to another.
Ninety-five percent of the serotonin in the body is located
in the GI tract, and the other 5 percent is found in the
brain. Cells that line the inside of the bowel work as
transporters and carry the serotonin out of the GI tract.
People with IBS, however, have diminished receptor activity,
causing abnormal levels of serotonin to exist in the GI
tract. As a result, they experience problems with bowel
movement, motility, and sensation—having more sensitive
pain receptors in their GI tract.
Researchers have reported that IBS may be
caused by a bacterial infection in the gastrointestinal
tract. Studies show that people who have had gastroenteritis
sometimes develop IBS, otherwise called post–infectious
Abdominal pain, bloating, and discomfort are
the main symptoms of IBS. However, symptoms can vary from person
to person. Some people have constipation, which means hard,
difficult-to-pass, or infrequent bowel movements. Often these
people report straining and cramping when trying to have a bowel
movement but cannot eliminate any stool, or they are able to
eliminate only a small amount. If they are able to have a bowel
movement, it may have mucus in it, which is a fluid that moistens
and protect passages in the digestive system. Some people with IBS
experience diarrhea, which is frequent, loose, watery, stools.
People with diarrhea frequently feel an urgent and uncontrollable
need to have a bowel movement. Other people with IBS alternate
between constipation and diarrhea. Sometimes people find that
their symptoms subside for a few months and then return, while
others report a constant worsening of symptoms over time
Points to Remember
IBS is a disorder that interferes with
the normal functions of the colon. The symptoms are crampy
abdominal pain, bloating, constipation, and diarrhea.
IBS is a common disorder found more often
in women than men.
People with IBS have colons that are more
sensitive and reactive to things that might not bother other
people, such as stress, large meals, gas, medicines, certain
foods, caffeine, or alcohol.
IBS is diagnosed by its signs and
symptoms and by the absence of other diseases.
Most people can control their symptoms by
taking medicines such as laxatives, antidiarrhea medicines,
antispasmodics, or antidepressants; reducing stress; and
changing their diet.
IBS does not harm the intestines and does
not lead to cancer. It is not related to Crohn's disease or
The most common dietary treatment for IBS has been, and still
is, a high fibre diet. While this is still a positive
recommendation for many patients, especially those who suffer
from constipation, some patients will not benefit from an
increase in dietary fibre, and in some the symptoms may even
worsen. As with any change in diet the increase in fibre
should be gradual, involve a variety of fibres and an adequate
fluid intake of at least 1.5 litres per day. The major sources
of fluid should be water, but dilute tea or juices may be
suitable in some patients. Caffeinated drinks such as coffee,
and carbonated soft drinks can aggravate symptoms and should
be limited, especially in the initial stages of dietary
IBS symptoms tend to be increased following large meals,
particularly if the meal is high in fat, and if the meal is
eaten quickly. It can be helpful to spread the food over 3
meals and 3 snacks per day. Avoid
eating quickly and try to relax after a meal. Regular light
exercise can also help reduce symptoms