Colonoscopy is a procedure that is performed by your gastroenterologist (GI), to look at the inner lining of your large intestine (rectum and colon). In this procedure, your GI will use a thin, flexible tube called a colonoscope to look at the colon. A colonoscopy helps find ulcers, colon polyps, tumors, and areas of inflammation or bleeding. During a colonoscopy, tissue samples can be collected (biopsy) and abnormal growths can be taken out. Colonoscopy can also be used as a screening test to check for cancer or precancerous growths in the colon or rectum (polyps).
In order to have a successful colonoscopy you will need to have a clean bowel, which means taking a strong laxative to clean out all the stool from your large intestine. This is achieved by taking a colon prep solution containing polyethylene glycol and electrolytes.
Although good for colonoscopy preparation, this type of bowel cleaning can rapidly deplete gut bacteria, which can also translate into a prolonged recovery from the colonoscopy when it is complete. Most patients can typically expect to take a couple of days to recover after a colonoscopy, and up to 20% of patients have abdominal symptoms. These are usually mild and self-limiting, such as diarrhea.
Research suggest that these alterations in gut microbiota may be because of the bowel cleaning procedure. This is important as our gut bacteria play an important role in gut health, immunity, and reducing inflammation, as well our ability to fend off illness and disease.
A study conducted by D'Souza. B., et al. at the Prince of Wales Private Hospital, Sydney, Australia, tested 260 patients in a randomized controlled trial, giving some patients a probiotic and some a placebo following their colonoscopy.
The results, published in ANZ Journal of Surgery, showed the probiotic group had 1.99 pain days while the placebo group had 2.78 days after colonoscopy. Among 20 patients with irritable bowel syndrome, probiotics reducing days of pain from 4.08 to 2.16.
Jalanka. J., at al at the University of Helsinki, Helsinki, Finland did a similar study on the effects of bowel cleansing on the intestinal microbiota. The investigators randomly assigned 23 healthy participants into two study groups. One group received two separate 1-L doses of a colon prep called MoviPrep, and the other group received a single, 2-L dose of MoviPrep. Fecal samples were collected at baseline, after bowel cleansing, and at 14 and 28 days after treatment.
In general, bowel cleaning resulted in a 31-fold decrease in microbial load. Approximately one quarter (22%) of participants experienced a marked alteration in the community composition of their microbiota after bowel cleansing. The shift in the microbial community was larger in the single-dose protocol than in the double-dose protocol.
Although the gut microbiome recovered to baseline after both protocols, the recovery was more rapid in the double-dose protocol than the single-dose protocol. Patients who received the larger, single dose of polyethylene glycol required as long as 1 month to recover their gut microbiome.
Physicians suggest that one way to mitigate this risk of depleting your gut bacteria and more rapidly replenishing your gut bacteria is to take a course of probiotic supplements just before and continue after the colonoscopy.