Understanding the role gut bacteria may play in GI function
Irritable bowel syndrome (IBS) and other functional gastrointestinal (GI) disorders are common. However, understanding of the underlying causes for symptoms are not yet clear. Recently researchers have been studying the role of normal intestinal bacteria (also called intestinal microbiota) in maintaining healthy and normal GI function.
Did you know?
- More than 1000 different intestinal bacteria live in your GI tract. There are actually 10 times more bacterial cells than human cells in the body.
- Most intestinal bacteria are not yet known and cannot be identified by routine tests.
- Some of the bacteria in our GI tract are helpful in keeping the normal functioning of our intestine and are beneficial to our health. Others may cause infection, inflammation, or may just make us feel sick.
What do we know about the intestinal microbiota in IBS?
Recent studies indicate that the bacterial communities in the intestine of some patients with IBS are different than the bacterial communities in people without IBS. What is “normal” is not yet well characterized.
The reasons for differences are unknown. It is not yet clear if these differences in the intestinal microbiota are the cause for the IBS symptoms, or a result of the abnormal intestinal function in these patients.
Can alterations in intestinal microbiota affect functional bowel symptoms?
There is evidence that the composition of the intestinal microbiota plays an important role in the development and functioning of the intestinal tract. It appears that changing the balance between “good” and “bad” bacteria in the intestine may lead to lasting effects on the function of the GI tract and chronic GI symptoms.
For example, bacterial infection in the GI tract (acute gastroenteritis) can sometimes lead to chronic IBS symptoms that may continue long after a person recovers from the initial sickness. This is called post-infectious IBS.
Learn more about post-infectious IBS
Another example is a condition called small-intestinal bacterial overgrowth (SIBO) where there are more bacteria than normal in the small intestines. This may result in excessive gas production and changes in the motility (movement) of the GI tract.
How do I know if I have altered intestinal microbiota?
Currently there are no tests that your doctor can order to determine if you have an altered composition of intestinal microbiota. Researchers use advanced molecular biology techniques to learn more about the different species of bacteria in the intestine.
What things may alter intestinal microbiota?
Several factors can affect the intestinal microbiota and lead to changes in the balance between the “good/beneficial” and the “bad/harmful” bacteria. These include:
- Diet and nutritional factors (e.g., fiber, sugars)
- The intestinal function (e.g., motility, secretion)
- Certain intestinal conditions (e.g., SIBO, infection, and inflammation)
- Medication (antibiotics, drugs that affect the intestinal motility)
How can altered intestinal microbiota be treated?
Recent research supports the importance of the balance between “good” and “bad” bacteria. Presumably, the “good” bacteria can be enhanced through treatment with probiotics or prebiotics (see below). The “bad” bacteria may be decreased by treatment with antibiotics. However, studies are still underway to determine which antibiotic, prebiotic, or probiotic should be used for treatment of different illness conditions, and how long each treatment course should last.
What are probiotics and prebiotics?
Probiotics are live microorganisms which when administered in adequate amount provide a health benefit in addition to their nutritional value. Prebiotics are food ingredients that can selectively promote the growth of the “good” intestinal bacteria.
Probiotics and prebiotics are considered as food supplements. They may be found in certain food products, or in over-the-counter preparations in the form of capsules, pills, and powders.
Is there evidence that probiotics can help in functional GI disorders?
Some beneficial effects of probiotics have been known for many years, but the data on the effects of probiotics in functional GI disorders is still limited. Most early studies were of poor design.
Only in the last few years have researchers began to gather more solid data on the use of probiotics in people with these disorders. These studies have shown that daily supplementation of diet with certain probiotics may be effective in improving intestinal function and some symptoms, such as bloating, gas, and discomfort. But while the more recent studies give us useful information, they also show that more research is needed.
How should I begin treatment with probiotics?
If you have persistent GI symptoms, discuss these with your doctor before attempting self-treatment. If you have a diagnosis of a functional bowel disorder such as IBS, you can discuss trying a probiotic supplement with your physician. Probiotics can be used alone or in combination with any other treatment.
What things should I be concerned about or take notice of while taking probiotic supplements?
Keep track of your symptoms to see if the probiotic you are taking is right for you. Certain probiotics may help some people, but can lead to new or worsening GI symptoms in others.
While generally relatively low-risk, side effects can occur. These may include abdominal bloating and gas, abdominal discomfort, loose stool, and itching in the area between the pubic bone and tail bone.
Do not expect immediate changes. Take the supplement as directed and observe your symptoms over several weeks. If you notice a worsening in your symptoms, stop taking the probiotic supplement and talk to your doctor.
How do I choose the right probiotic supplement?
Not all probiotics are the alike and not all available probiotic formulations will be effective for everyone. Some may even be harmful when given to patients with certain diseases.
Make sure you:
- Consult your doctor before beginning any regimen of regular probiotic consumption.
- Remember most of the available probiotic products were not tested in clinical trials in patients with functional GI disorders.
- Look for probiotic products that were clinically tested for the specific condition and symptoms you are looking to improve.
If this doesn’t work, what should I do next?
Your personal GI symptoms may react differently than expected, or not at all, to probiotic supplements. There is no reason to continue taking probiotics if they do not help with your symptoms.
Many factors contribute to functional GI symptoms. Altered intestinal microbiota may be one of these. Treatment with probiotics may yield promising results for those suffering from functional GI symptoms.
Talk to your doctor about all available treatments. Stay up-to-date with the latest clinical data about functional GI disorders. The understanding of these conditions is constantly being updated with new findings and options for treatment.
Adapted from “Probiotics”- IFFGD Publication #246 by Nancy DeMaria, Danielle Maier, PA-C, Yehuda Ringel, MD, University of North Carolina Center for Functional GI and Motility Disorders, Chapel Hill, NC.