Irritable bowel syndrome (IBS) is an exceedingly common gastrointestinal disorder mainly affecting people in Westernized countries. IBS-C, a subtype of IBS, is the name for IBS dominated by constipation.
IBS is an elusive condition—scientists don’t exactly understand how or why it starts. But dysbiosis (a fancy name for microbial imbalances in the gut), diet, and stress all seem to play a part.
If you are following along with this probiotic series, you know that probiotics can be a very effective therapeutic strategy for various problems. You also understand that probiotics are strain-specific and, depending on the situation, don’t do much at all.
So, this brings us to our next question. Are probiotics good for IBS-C? And what about IBS-D and even IBDs, inflammatory bowel disorders?
Are Probiotics Good for IBS-C? Yes! Probiotics can help with constipation
It is thought that dysbiosis is strongly linked to IBS-C. Studies have found that those with IBS-C have a significantly decreased abundance of the beneficial bacteria called Bifidobacteria, Lactobacillus, and Faecalibacterium prausnitzii (1).
Disturbances of healthy gut microbiota, like SIBO and gut infections, often co-exist with IBS.
In fact, antibiotics are often a treatment of choice for IBS-C to kill off the overgrowth of potentially pathogenic bacteria that might be causing IBS-C symptoms. But, of course, antibiotics can also create undesirable side effects.
In a 2017 study, researchers found that four weeks of twice-daily supplementation with the probiotic Lactobacillus reuteri DSM 17938 significantly improved bowel habits in adults with chronic constipation while also reducing methane-producing bacteria (2).
In this study, participants’ average bowel movements per week increased from 4.1 to 6.4, which is a massive improvement for someone with chronic constipation. Unfortunately, stool form did not change much, and most participants remained between 1-3 on the Bristol Stool Scale, meaning their stools were hard and pellet-like.
But, the probiotic significantly reduced methane production and clinically eradicated methane in 55% of methane-producing participants (2).
What does this mean in the real world?
Methane is produced by bacteria such as Methanobrevibacter smithii, and is strongly linked to IBS-C and slow bowel transit time. Sometimes those with SIBO also have high methane levels and accompanying constipation.
Other studies have confirmed that this strain effectively reduces abdominal pain, bloating, and feelings of incomplete defecation (3) and increases weekly bowel movements (4).
You can find Lactobacillus reuteri DSM 17938 in BioGaia Protectis and BioGaia Gastrus.
Are Probiotics Good for IBS-C? Yes! Probiotics can speed up transit time
Folks with IBS-C have a significantly longer gut transit time than those without IBS-C. Transit time is the amount of time it takes for food to pass through your system entirely. This might look like 24 hours in a normal gut, but it might be 50 hours or more in someone with IBS-C.
Luckily, probiotics can be very effective at speeding up transit time, resulting in less constipation and possibly less dysbiosis.
A randomized placebo-controlled trial found that two weeks of supplementation of Bifidobacterium lactis HN019 significantly reduced whole gut transit time in a group of chronically constipated adults. This group was not officially diagnosed with IBS-C, but they reported an average of only 1-3 bowel movements per week and symptoms such as abdominal pain, flatulence, nausea, and regurgitation. The probiotic was given at a high dose of 17.2 billion CFU and a low dose of 1.8 billion CFU; both were effective (5).
Amazingly, two weeks of supplementing with 17.2 billion CFU of Bifidobacterium lactis HN019 shortened transit time by 33%, dropping from an average of 49 hours to 21 hours!
The lower dose was also very effective, reducing average transit time from 60 to 40 hours. The placebo group had no change in transit time.
Both probiotic groups also saw the benefit of significantly less abdominal pain, nausea, stomach gurgling, irregular bowel movements, flatulence, and regurgitation (5).
Bifidobacterium lactis HN019 can be found in Metagenics Ultra Flora Acute Care.
Probiotics are good for IBS-C, but fiber and prebiotics might be even better
While probiotics are beneficial microbes that positively support the gut ecosystem, fiber is the fuel for your resident good gut bugs. Consuming fiber supports helpful native microbes, allowing them to thrive, multiply, and push out pathogenic bacteria.
A large systematic review found that daily consumption of soluble fiber effectively improved IBS symptoms and relieved constipation in those with IBS-C (6).
Insoluble fiber, however, had little effect and even worsened IBS symptoms for some (6).
Good supplemental sources of soluble fiber are psyllium husks, freshly ground flax seeds, freshly ground chia seeds, and slippery elm powder.
Prebiotics are a type of fiber that increase very specific bacterial populations in the gut. Many fiber-rich foods contain prebiotics, such as Jerusalem artichokes, chicory, leeks, asparagus, onions, and garlic.
Specific prebiotics have been studied for their beneficial effects on IBS. A 2021 review suggested that daily prebiotics in the form of inulin may be helpful for those with IBS-C, as it can increase stool frequency and has a stool-softening effect (7). Doses near 12 grams may be needed to get this effect which can be challenging to get from food alone. However, Jerusalem artichokes are an excellent source of inulin, and it is also available as a supplement.
Disclaimer: Jerusalem artichokes can increase flatulence when consumed in high amounts, hence the moniker “fartichokes.” This can be true of many prebiotic-rich foods, and certain individuals are more sensitive to their effects. So, start with small amounts and see how you respond. And don’t worry—farts (as opposed to painful gas that feels “stuck”) are a good sign that your prebiotics are feeding the good guys. 🙂
Are Probiotics Good for IBS-D?
The answer is yes!
Just like certain probiotics are good for IBS-C, some probiotic strains are equally effective at improving symptoms of IBS-D.
Bacillus coagulans MTCC 5856 is a spore-based probiotic that may reduce abdominal pain, diarrhea, stool frequency, bloating, and vomiting in those with IBS-D (8). In this particular study, the dose was 2 billion CFU for 90 days (8). Bacillus coagulans MTCC 5856 can be found in Xymogen ProbioMax IG 26 DF.
A 2018 randomized placebo-controlled trial showed excellent results with three months of supplementation with a multi-strain probiotic containing 14 strains of Lactobacillus, Bifidobacterium, Bacillus, and Streptococcus. In this study, those with IBS-D had an average of 6.1 bowel movements per day at baseline. That number dropped to 2.5 at the 5-month follow-up!
You can find this probiotic combo in Bio-Kult probiotic. (9).
And what about probiotics and IBD?
Yep, specific probiotic strains are helpful for IBD, too.
A 2020 systematic review of 21 clinical trials concluded that probiotics might effectively lower inflammation and balance the gut microbiome in those with IBD. The majority of studies provided solid evidence that probiotics can influence remission in IBD and seem to work best for those with ulcerative colitis. However, patient bio-individuality may play a big part in this observation (10).
The most well-supported probiotic for IBD is a multi-strain formula called VSL #3 (10). It contains eight strains of Lactobacillus, Bifidobacterium, and Streptococcus.
The VSL #3 website claims their probiotic is good for IBS, as well. However, a meta-analysis of 5 randomized controlled trials found that VSL may not be as effective for IBS, as supplementation only slightly improved IBS symptoms (11).
So, to conclude, are probiotics good for IBS-C? Yes - as long as they are strain specific!
Something else to consider when looking at studies like these is that they are only controlling for one thing…probiotic supplementation.
That means that participants in these trials are not changing their diets, exercising more, or practicing stress management or mindfulness.
So, imagine what the results would look like if there were lifestyle shifts plus a nutritional intervention combined with the proper probiotic and/or prebiotic. That could be life-changing!
Just one more fun fact before you go…
Let's talk briefly about the placebo effect and IBS-C and what that means for you.
The placebo effect happens when someone’s symptoms significantly improve without receiving any treatment eliciting a physiological change. This happens because simply thinking you are doing something to help yourself activates several neural systems, triggers brain activity, and then eases symptoms.
About 40% of participants in IBS clinical trials experience a placebo response (12). This is troublesome for researchers because it makes it difficult to get accurate and significant results.
But it shows us that our nervous system and mind wield incredible power.
For example, women with IBS who participated in a mindfulness group experienced a 26.4% drop in symptom severity immediately afterward, and this increased to a 38% reduction in symptoms three months later (13). That’s a powerful change.
So, hopefully, this drives home the point that when it comes to IBS and IBD, a whole-body approach will always give you the best results. And probiotics should definitely be part of the protocol.