Is SIBO or SIFO (Small Intestinal Bacterial/Fungal Overgrowth) Causing Your IBS?

In my last blog post, Looking Beyond an IBS Diagnosis, I discussed what having IBS (Irritable Bowel Syndrome) really means, and why it's important to look beyond this diagnosis, because we now know that there are treatable conditions responsible for IBS symptoms. These are referred to the 'root causes' of IBS, and over the next series of blog posts, I will discuss the the most common IBS root causes I see in my 1:1 clients, and those who complete my IBS Protocol.

This applies to you even if you don't have an official IBS diagnosis. If you have problems with bloating, gas, diarrhea, constipation, reflux, nausea, undigested food in your poop, or autoimmunity, keep reading!

What is SIBO?

SIBO stands for Small Intestinal Bacterial Overgrowth and is defined as an increased number of bacteria in the small intestine.

What is unique about SIBO is that these bacteria move to where they don’t belong and colonise the small intestine, a region that should contain very limited numbers of bacteria.

Because these bacteria are supposed to be in the large intestine, they are mostly species that ferment carbohydrates and the byproduct is either hydrogen or methane gas both of which will result in abdominal bloating. But just like IBS, SIBO sufferers are usually divided into one of three different categories:

Hydrogen SIBO - mostly associated with diarrhea, but sometimes alternating constipating and diarrhea.

Methane SIBO - associated with constipation.

Hydrogen Sulfide SIBO - associated with rotten egg smelling gas.

From this graphic we can see that the stomach contains the least amount of bacteria and this is because it is a highly acidic condition. And then the small intestine has a little more bacteria but in comparison to the large intestines it is virtually barren. So what we see in SIBO is bacteria moves from the large intestines to the small intestine where it doesn't belong. Remember these are species that ferment carbohydrates or feed on carbohydrates creating gas as a byproduct which can result in the types of symptoms we see an IBS, like bloating indigestion gas and irritable bowels.

This is really the reason why we see such success with a low FODMAP diet when it comes to IBS because FODMAPs are fermentable carbohydrates and this is the bacteria's main food source. So by removing these foods the bacteria no longer has anything to feed on and therefore no longer produces gas. But the problem with this is that you end up starving your good guys at the same time, and when you have low levels of beneficial gut bacteria this can cause problems in itself. This is another reason why finding your root is so important so that you don't have to remain on a restrictive diet in the long-term.

Prevalence of SIBO in IBS patients

SIBO is actually a subset of IBS. Not all IBS is SIBO, but The prevalence of IBS is about 10%, so that's about one out of 10 people will have some digestive disorder that actually is IBS.

Estimation is that SIBO is about 60 to 80% of all worldwide cases of IBS, so that's a huge number, and means it's possible that we are looking at about 500 million SIBO cases worldwide, and of course the vast majority doesn't know that they have SIBO. In the past five years, every time I check PubMed, which is a research database, there's just hundreds and hundreds more research studies that are coming out, which is really exciting for you, the SIBO sufferer, to understand this condition more and successfully treat it.

Common SIBO Symptoms