The collection of communities of bacteria and other microorganisms living in the gut (the micro-biome, or microbiota) plays important roles in human health. This has become increasingly clear over the past decade. Concurrently, interest in the use of probiotics as a functional food has increased dramatically among the general public. Naturally, people with inflammatory bowel disease (Crohn’s disease and ulcerative colitis) are also intrigued by the possibility that probiotics may be of use in the management of their conditions.

The good news is this: Although there is little evidence that probiotics are of any real benefit in the management of Crohn’s disease, there is growing evidence that probiotics may be of genuine benefit in the treatment of ulcerative colitis. Probiotics have shown clinically significant benefits in both the induction and maintenance of disease remission, in the maintenance of remission after surgery, and in the prevention of pouchitis.

What Are Probiotics?

Probiotics are live microorganisms that are adapted to living in the human gastrointestinal tract. These diverse communities of bacteria have co-evolved with us. They are sometimes called “friendly” bacteria. And for good reason. Their functions are numerous. They contribute to the proper functioning of the immune system, extract otherwise unavailable nutrients from food, produce vitamins and other beneficial substances, and generate products such as defensins; protein fragments that contribute to the gut mucosa’s ability to fend off disease-causing germs. Some microbes contribute to the gut’s ability to resolve inflammation. A diverse community comprising numerous species of microbes—the microbiome—clearly plays an integral role in immunity.

Inflammatory Bowel Disease (IBD) involves immune system dysfunction. No one knows the exact cause of Crohn’s disease and ulcerative colitis, but we do know they involve disturbances in both the normal functioning of the immune system and within the gut microbiome itself. Ulcerative colitis, in particular, is thought to be an autoimmune disease, in which the immune system mistakenly identifies harmless cells in the lining of the colon (the intestinal mucosa) as threats, and attacks them. Ordinarily, this sort of inflammatory response would be appropriate, quick, and promptly resolved. But in the case of IBD, inflammation is more or less chronic. During periods of quiescence—known as remission—inflammation and symptoms may subside. But both Crohn’s disease and ulcerative colitis are chronic conditions that must be managed with constant vigilance.

Mounting evidence suggests that the regular use of carefully selected and approved strains of beneficial probiotics may help sustain remission once it has been achieved in ulcerative colitis. Note, though, using probiotics to achieve or sustain remission should only be done with your doctor’s guidance and approval. While numerous products have flooded the market in recent years, few specific strains of probiotic organisms have been studied scientifically to determine their safety and effectiveness, or even their proper dosing. Together, you and your doctor(s) can weigh the pros and cons of probiotic use for your condition.

The Evidence

Further research is needed, but presently available research shows that certain strains of probiotic bacteria can be clinically useful for the maintenance of disease remission in ulcerative colitis. Unfortunately, probiotics do not appear to be of particular benefit in Crohn’s disease.

Not all research is created equal, however. The “randomized controlled trial”, or RCT, is considered the gold standard for medical research. Randomized, double-blind, placebo-controlled studies (RCTs) are clinical trials that ideally enroll large numbers of human subjects. Subjects are randomly assigned to receive either an active substance or an inactive placebo, in a blinded fashion (neither subjects nor researchers know who gets which substance). The results from these sorts of trials receive the most weight, because they establish causation. Lesser trials can establish associations, but they cannot claim to prove that “A” causes “B”.

Probiotic Mix VSL#3® and E. coli Nissle

A product called VSL#3 contains eight species of live, freeze-dried probiotic bacteria, including: Bifidobacterium breve, Bifidobacterium longum, Bifidobacterium infantis, Lactobacillus acidophi-lus, Lactobacillus plantarum, Lactobacillus paracasei, Lactobacillus bulgaricus and Streptococ-cus thermophilus.

Several clinical trials have generated high-quality evidence that VSL#3 is capable of inducing remission of mild-to-moderate ulcerative colitis disease activity among some patients. Some lesser quality evidence shows that another probiotic, E. coli Nissle, is also capable of inducing remission. Other trials have demonstrated that VSL#3 or E. coli Nissle are capable of maintaining remission of disease activity, once it had been achieved, usually through drug therapy. Most studies have established that probiotics are safe and well tolerated.


Surgery for ulcerative colitis involves the removal of the entire colon and then typically the creation of a structure called an ileal pouch-anal anastomosis. Inflammation of this ileal pouch—a condition called pouchitis—is one of the most common complications of this procedure. Within ten years after surgery, up to 46 percent of patients are stricken with pouchitis.

Studies have shown that treatment with products such as VSL#3 may be useful for both the induction and the maintenance of remission in pouchitis. It may also be used to prevent pouchitis from developing in the first place. A new randomized, prospective study has concluded that the long-term use of the probiotics, Lactobacillus and Bifidobacterium, supplied by a product called Trilac®, can prevent pouchitis from occurring, and reduce the severity of the condition. Some of the microbes used in the study are also included in the probiotic formulation, VSL#3.