This is a huge problem for a lot of us. It’s not that we don’t go daily – for those of us who do – but when we go it’s only partially complete. Anyone with this condition knows that this often leads to IBS symptoms as the day progresses. Some people just take a longer time to go. Sometimes excess gas makes the process take even longer. The reasons for this have never been explained but this is what I’ve experienced.
(if you want to jump to the diet that makes this easier, here it is:)
Non-IBS people get constipation as well, but don’t have the symptoms that we do. This could be because they effectively digest their food. If they suffer from constipation, they just get constipation. If a non-IBS person has constipation, unless they tell you, you wouldn’t know.
IBS sufferers on the other hand know that there are certain foods they can’t digest well. This means that these nutrients escape digestion and travel through the small intestine and colon, feeding bacteria. The fermentation creates Short Chain Fatty Acids (SCFAs).
As undigested stool passes through the small intestine and colon, it will increasingly fill with gas. This is the origin of gas in IBS. Dr Mark Pimentel pioneered a study which showed that about one third of us produce methane, which causes constipation in IBS. Other people convert methane to hydrogen, leading to diarrhea (IBS-D).
This could account for all the different sub-groups in IBS. It’s still the same underlying cause – maldigested food – but it affects people differently according to their bacterial make-up.
Methane can act as a neurotransmitter, meaning it can affect the muscular contractions of the colon, or peristalsis. On a physical level, pockets of gas can also impede the passage of stool. The end result is that a lot of gas in the colon will lead to an inefficient bowel evacuation.
For me though, incomplete evacuation is characterised by gas. The more gas, the longer it takes & the more difficult it all is. Reduce the gas by reducing the fermentable substrate (excess sulphur from animal protein, starches (especially grain starch), FODMAPs, dairy, nuts) and you might also reduce evacuation time.