IBS pain is quite a bit different than pain in other areas of the body. If you just apply pressure to your arm, the pain is mild if you even get it. But if you cut your arm, the pain can become intense.
This story is completely flipped in the gut. If you have surgery to your intestines, the incision piercing your intestine won’t hurt. However, create lots of pressure with gas and the pain can be agonizing. As a result, people with IBS experience quite a bit of pain with bloating.
The crazy thing about this is that if you create the same amount of gas in a person without IBS, they experience no pain whatsoever. This is because people with IBS have something called visceral hypersensitivity, which causes them to be more sensitive to pressure in the gut.
Interestingly, quite a bit of evidence points to histamine as a cause of visceral hypersensitivity in people with IBS . You likely know of histamine because of its role in allergies. We recently covered histamine in a few blogs you can check out here:
A new paper identifies a potential culprit for the overproduction of histamine in some people with IBS.
IBS pain, histamine, and FODMAPs
Most people with IBS are likely familiar with FODMAPs. FODMAPs are rapidly fermentable carbohydrates that often elicit symptoms in people with IBS.
As such, a low FODMAP diet is a popular first step to getting IBS under control for many people. If you’re unfamiliar with FODMAPs and how they contribute to IBS symptoms, check out this video:
For the most part, the assumption is that reducing FODMAPs reduces bloating, which is how it reduces symptoms in people with IBS. However, it’s actually a little more complex than that.
While reducing FODMAPs does reduce bloating, it also shifts the microbiome in a positive way. In particular, which metabolites it produces. A recent study we covered on the blog showed how the changes in metabolites in people who respond to a low FODMAP diet suppress symptoms. Check that out here:
This new paper identifies a member of the microbiome known as Klebsiella aerogenes as a major producer of histamine in the gut in some people with IBS. In people with IBS who are colonized with this microbe, the excess histamine causes visceral hypersensitivity. When fed a low FODMAP diet, mice colonized with this microorganism produce LESS histamine.
This is due to changes in metabolites created by the microbiome in a low FODMAP diet. These metabolites change the pH and other environmental factors leading to inhibition of the enzyme these bacteria use to create histamine.
Another interesting finding is that, at least in mice, it’s the histamine-4 receptor that causes these problems. Therefore, if we can find a way to block this receptor, we may be able to address IBS pain symptoms.
It’s important to point out that IBS is a syndrome, and as such, is unlikely to have a single cause for everyone. Your IBS pain may differ from another person’s IBS pain. Therefore, approaches to address the problem may differ.
It does seem that excess histamine seems to be pretty consistently associated with IBS. However, what causes this in each individual differs, and even people not colonized with K. aerogenes can have issues with histamine. A low FODMAP diet may help some, but not others.
If you have IBS and haven’t yet, a trial of the elimination phase of the Low FODMAP diet may be a critical first step to finding a diet that works to help you control your IBS pain.