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Why Gut Transit Time is Crucial for Digestive Health

Why Gut Transit Time is Crucial for Digestive Health

We know that a sign of good gut health is regular bowel movements, but it can be a bit more complicated than that. Let’s talk about why gut transit time is crucial for digestive health.

What is Gut Transit Time (GTT)?

Gut transit time (or bowel transit time) is the length of time it takes food to get from your mouth and into the toilet as a bowel motion.

As many of my lovely patients know, I discuss GTT quite regularly in my appointments, especially when you first start to see me, and most especially when you are reporting issues with things like constipation, bloating, nausea, headaches, food intolerances, skin problems, and/or seeing me for other ongoing, or even transient, gut issues.

When I first ask people about the regularity of their bowels, and start to discuss GTT, lots of people may say, “That’s easy for me to work out, as I’m not constipated. I open my bowels daily, so it must be coming out within 1-2 days.” But is that what is actually happening? Just as it’s easy to assume that someone who is constipated has slow transit (you’d likely be right in this instance), it’s equally as easy to assume that if people who are opening their bowels daily, they will have a faster transit time – but this may not be the case at all! 

I’m very suspicious of “hidden” slow transit when someone tells me that they’re opening their bowels daily, but are regularly feeling bloated, heavy in the gut and may also be distended too (belly is sticking out), especially if this gets worse by the end of the day. GTT is an important thing to assess, as slow transit can be a hidden cause of some gastrointestinal symptoms and can also make you feel sluggish and “blah” if your stool (poo) is sitting in the gut for too long “stewing”.

People who are constipated, automatically have a slower transit, but it is still important to assess how long their GTT is too, because their stool can be taking much longer to come out than you think e.g. 7-14 days (or more in some cases)! And if I am going to prescribe someone prebiotics, I need to know what their GTT is, as slow transit may contribute to someone having poorer tolerance to prebiotics and more pronounced adverse effects like bloating and wind.

How can you find out your Gut Transit Time (GTT)?

Well, it’s a simple trick I have learnt over the years from my training with Dr Jason Hawrelak, and it is quite an easy and cost-effective test that you can do at home. I usually get my patients to test their GTT whilst they are also keeping me a lovely stool diary (using the Bristol stool scale) for 10-14 days, so they can keep all the information in one place.

Home test for working out your Gut Transit Time:  

  • You can either eat a whole cooked corn on the cob (not a few mouthfuls or a tiny cobette), or at least ½-¾ cup of cooked white quinoa or have a couple of tablespoons of whole sesame seeds.
  • It’s important that you have not had any corn on the cob, quinoa, or large amounts of sesame seeds for over a week before you start this test, because if your transit time is slow, corn can still be coming out of the colon for days, or, sometimes even weeks, later.
  • Similarly, once you have had the corn or sesame seeds, don’t have them again until the “test” corn/quinoa/sesame seeds have stops being passed.
  • Your food of choice does not have to be chewed well because you’ll need to keep watching for the corn, quinoa or sesame seeds to appear in your stool, and when it stops appearing too – the less chewed it is, the easier it will be to see.
  • You need to note:
    • Date and time the corn/quinoa/sesame seeds were eaten
    • Date and time when it started to appear in the stool
    • When it stopped appearing in the stool e.g., it’s not uncommon for people to tell me that the corn took 2-3 days to appear, but then they were passing corn for 3-4 days (this all means something)

What is the ideal Gut Transit Time (GTT)?

Ideally, you want your transit time to be within 14-24 hours, but I’ll be okay with my patients being up to 36 hours, although I’ll still suggest some small supports. Once it starts to get beyond 36 hours, we are heading into the slower transit time category, especially when people come back with a GTT of over 2-3 days and sometimes many days beyond this! Just as a heads up, using things like laxatives will not fix underlying GTT issues!

Is there a way to improve Gut Transit Time (GTT)?

Yes, of course, but we need to nut out the underlying contributing factors, especially if you are constipated or feeling really bloated and sluggish. Sometimes working it out may involve microbiome analysis, especially if you are constipated, to see if there are any microbiome imbalances or overgrowths of bugs like Methanobrevibacter smithii (an archaea, not bacteria), that may be slowing down the bowel.

Sometimes I may suggest certain dietary interventions, specific strains of probiotics, specific prebiotics, and lifestyle changes, but this depends on how you are presenting at the time and, of course, your personal health history. 

I hope this information gives you more of an idea of why gut transit time is crucial for digestive health and why it’s something to keep an eye on!

Feeling like your GTT may be too slow? Book into see me so you can receive advice that is tailored to your specific situation.

Want to read more about gut health? Read my gut blogs here.

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