Introduction
The term “irritable bowel syndrome” (IBS) is used to describe chronic
colon problems that occur in the absence of an identifiable medical cause. Common
symptoms include alternating diarrhea and constipation, excess intestinal gas,
intestinal cramping, uncomfortable bowel movements, abdominal discomfort following
meals, and excessive awareness of the presence of stool in the colon. Despite all
these distressing symptoms, in IBS, the intestines appear to be perfectly healthy
when they are examined. Thus, the condition belongs to a category of diseases that
physicians call “functional.” This means that while the function of the bowel
seems to have gone awry, no injury or disturbance of its structure can be
discovered. (The analogous problem in the stomach is called dyspepsia, and the two
conditions frequently overlap.)
Because the cause of IBS is not understood, conventional medical treatment of
IBS is highly inadequate. One drug that had shown promise, Zelnorm, was withdrawn
from the market for safety issues. Another, Lotronex, was temporarily withdrawn,
and then approved again, but only under strict limitations. Other medical
treatment approaches for IBS include increased dietary fiber, drugs
that reduce bowel spasm, and drugs to address constipation or diarrhea as needed.
In addition, various forms of psychotherapy, including hypnosis,
have been tried, with some success.
Principal Proposed Natural Treatments
Peppermint. Peppermint oil is widely used for IBS,
and the evidence suggests that it is probably useful. A majority of
placebo-controlled studies have found peppermint oil to be more effective than
placebo. However, most of these studies are small.
Probiotics. Numerous double-blind trials indicate that various
probiotics (friendly bacteria) may be helpful for IBS. In a
six-week, double-blind, placebo-controlled trial of 274 people with
constipation-predominant IBS, in which constipation is a more significant symptom
than diarrhea, the use of a probiotic formula containing the bacterium
Bifidobacterium animalis significantly reduced discomfort and
increased stool frequency. In another randomized trial, 266 women with
constipation who consumed yogurt containing B. animalis and the
prebiotic fructo-oligosaccharide twice daily for two weeks experienced significant
improvement in their symptoms compared to women consuming regular yogurt as
placebo. (Prebiotics are substances that encourage the growth of beneficial
bacteria in the colon.)
Another study examined the effects of four weeks of treatment with the bacterium Lactobacillus plantarum on intestinal gas in sixty people with IBS. This study found benefits that persisted for an entire year after treatment stopped.
Benefits were seen also in eight other small double-blind trials, using L. plantarum, L. acidophilus, L. rhamnosus, L. salivarus, and Bifidobacterium, and proprietary probiotic combinations including various strains.
However, there have been a number of negative studies too. Two studies that pooled previous randomized trials on the use of probiotics for IBS came to similar conclusions: Probiotics appear to offer some benefit, most notably for global symptoms and abdominal discomfort. However, these two studies were unable to determine which probiotic species were most effective.
Flaxseed. In a double-blind study, fifty-five people with chronic
constipation caused by IBS received either ground flaxseed or
psyllium seed (a well-known treatment for constipation) daily for three months.
Those taking flaxseed had significantly fewer problems with constipation,
abdominal pain, and bloating than those taking psyllium. The flaxseed group had
even further improvements in constipation and bloating while continuing their
treatment in the three months after the double-blind study ended. The researcher
concluded that flaxseed relieved constipation more effectively than psyllium.
Chinese herbal medicine. Chinese herbal
medicine is traditionally practiced in a highly
individualized way, with herbal formulas tailored to the exact details of each
person’s case. In a double-blind, placebo-controlled trial, 116 people with IBS
were randomly assigned to receive individualized Chinese herbal treatment, a
“one-size-fits-all” Chinese herbal formulation, or placebo. Treatment consisted of
five capsules three times daily, taken for sixteen weeks. The results showed that
both forms of active treatment were superior to placebo, significantly reducing
IBS symptoms. However, the individualized treatment was no more effective than the
“generic” treatment.
Other Proposed Natural Treatments
One study found evidence that pancreatic digestive enzymes (including
proteolytic
enzymes plus other enzymes called lipases) might be helpful
for reducing the flare-up of IBS symptoms that may follow a fatty meal. Three
small studies suggest that the use of the supplement melatonin might reduce
symptoms of IBS; it has been suggested that the hormone melatonin may have an
effect on the nervous system in the digestive tract.
An herbal combination containing candytuft, matricaria flower, peppermint leaves, caraway, licorice root, and lemon balm has shown some promise for IBS. In one double-blind trial, a combination of lemon balm, spearmint, and coriander showed some promise for reducing symptoms of diarrhea-dominant IBS.
The herbs Coleus forskohlii and slippery elm and the
supplement glutamine are also sometimes recommended for IBS, but there is no
meaningful evidence that they are helpful. One double-blind study failed to find
either the herb fumitory or an herbal relative of turmeric helpful for IBS.
The prebiotic supplement fructo-oligosaccharides has been
advocated as a treatment for IBS. However, research results are inconsistent at
best. For example, a six-week double-blind study of 105 people with mild IBS
compared 5 grams (g) of fructo-oligosaccharides (FOS) daily with placebo and
returned conflicting results. According to some measures of symptom severity
employed by the researchers, the use of FOS led to an improvement in symptoms;
however, according to other measures, FOS actually worsened symptoms. Conflicting
results, though of a different kind, were also seen in a twelve-week,
double-blind, placebo-controlled study of ninety-eight people. Treatment with FOS
at a dose of 20 g daily initially worsened symptoms, but over time this negative
effect wore off. At no time in the study were clear benefits seen, however. On a
positive note, one study did find benefit with a combination prebiotic-probiotic
formula.
Food
allergies may play a role in IBS, and diets based on
identifying and eliminating allergenic foods might offer some benefit.
Hypnotherapy has shown some promise for IBS, as has
relaxation therapy.
Acupuncture has been proposed as a treatment for IBS.
However, study results have failed to show it effective. For example, a
thirteen-week study of sixty people with IBS found fake acupuncture just as
beneficial as traditional acupuncture. A larger trial of 230 adults with IBS found
that acupuncture (six treatments over three weeks) was not associated with
improved symptoms or severity compared to sham acupuncture.
Bibliography
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