Is Metamucil Good For IBS?


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The first thing to understand when looking at whether Metamucil is good for IBS is that IBS is a complex condition, with several variants and a lengthy list of possible symptoms.

There are, for instance, 3 main types of IBS: IBS with constipation, IBS with diarrhea, and IBS a mix of alternating constipation and diarrhea.

The idea that one treatment will be effective against all variants of IBS and their frankly contradictory symptoms is therefore very unlikely.

But can it help with one or more variants?

Before we go much further, let’s be clear on what Metamucil actually is.

What is Metamucil?

Metamucil (also known as psyllium) is a type of dietary fiber. There are broadly speaking two kinds of dietary fiber.

Insoluble fiber, as the name suggests, does not dissolve in water, and it can’t be broken down by your intestine and its enzymes. It adds bulk to your stools and can pull more fluid into the gut.  It can speed up transit of intestinal contents through the bowel, which may help with constipation.  It can be found in wheat bran, whole grains, and vegetables.

Soluble fiber on the other hand, does dissolve in water, forming a kind of gel, and may help with stool form. It slows down digestion.  It can be found in psyllium, oat bran, barley and beans.

Of this soluble fiber, there are two subtypes: Highly Fertmentable and Moderately Fermentable.

Highly fermentable soluble fiber can be a real pain in the gut, because it can be fermented in the colon leading to a lot of gas and bloating. More gas is never good.

Moderately fermentable soluble fiber produces much less gas, which is helpful for people with IBS. Metamucil is one of these moderately fermentable soluble fibers.

That’s great – the less discomfort for our guts, especially with IBS, the better. But is there any evidence that it does you good if you have IBS?

Metamucil Effect on IBS with Constipation

Well… yes. And then again… no.

Which is a cutesy way of saying that science is currently divided on whether Metamucil actually has any genuinely beneficial effect on IBS with constipation.

A 2012 meta-analysis by the esteemed British Medical Journal in the UK concluded not just that the matter was inconclusive – it went as far as to say there were no benefits to either soluble or insoluble fiber for people suffering from IBS.

However, that contradicted an earlier, 1997 meta-analysis by the American Gastroenterological Association, that found Metamucil was associated with “a small improvement in symptoms of IBS compared to placebo.”

A placebo of course is a neutral alternative, designed to make the patient think there is an active ingredient, when there really isn’t. It’s used to measure the suggestibility of patients to a treatment that they think will do them good.  

A meta-analysis published by the American Journal of Gastroenterology in 2014 concluded that soluble fiber was effective in treating IBS.  The current guidelines published on the diagnosis and treatment of IBS do recommend soluble fiber as a first line treatment for IBS, although point out that evidence is weak.

The point though is that IBS is an unpleasant, uncomfortable, painful, and alarmingly widespread condition (around 10-15% of the United States population), and with a low risk of side effects and possible benefit, fiber is recommended early on in the treatment of IBS.  

Due to its properties and ability to regulate bowel habits, it can be recommended for IBS-C and IBS-D.

Metamucil does retain the water in which you have to dissolve it in order to take it, all the way to your intestine. There, it swells, to form a gelatinous mass, which, it’s believed, makes your stool softer, which is perceived as a beneficial effect for sufferers of IBS with constipation, who tend to have hard, dry and pellet-like stools.

Also, the swelling effect increases the bulk of your stool. How is that good if you have constipation? It’s believed that the increased size triggers peristalsis in your colon, to get you going more easily and speed the transit time through your bowel.

Combining increased peristalsis with softened stools is believed to account for the recorded small difference between Metamucil and a placebo.

Another possible benefit of Metamucil for IBS is that it may help the ‘good bacteria’ in your colon, to help regulate gut dysbiosis. People also believe it boosts the immunity of your gastrointestinal tract.

While the data on Metamucil is limited and sometimes conflicting, taking in dietary fiber is a good thing to do in general, and also has some proven health benefits for people with other conditions.

If you have diabetes, Metamucil can be your friend, by, for instance, slowing down the absorption of sugar into the bloodstream. The expanded gel in the intestine turns the rush of sugar into your bloodstream into a slower, more controlled process – and therefore regulating the impact of – additional sugar in your food.

Metamucil also helps people with heart disease or high cholesterol, decreasing the levels of cholesterol in the blood.

Metamucil for IBS Symptom-Management?

Because of its known health benefits as a sponge or a barrier to the likes of sugar and cholesterol to slow down their absorption into the bloodstream, dietary fiber has been defined as a good thing for years.

In yet another meta-analysis in 2017 by the International Journal of Molecular Medicine, the issue of whether IBS symptoms could be treated or reduced through Metamucil wasn’t the question. What was asked was how effective the different kinds of dietary fiber were in having a positive impact on IBS.

In the analysis, the Journal recommended Metamucil over other types of dietary fibers, for all versions of IBS. That said, it acknowledged that the effects you’ll get from using Metamucil vary a lot.

The effects vary depending on which subtype of IBS you have, the dose of Metamucil you take, and individual factors (like your other health conditions, medications and even prior abdominal surgeries).  Because of this, there’s no hard and fast rule about the recommended dosage or what effects you might expect from it. 

Ultimately, the answer is that it’s worth trying, but there are no guaranteed results to its use for any subtype of IBS as yet. Research is ongoing though, so watch this space.

Here are other articles on management of IBS symptoms: