Exploring the Connection Between IBS and Caffeine

Exploring the Connection Between Caffeine and IBS

If you suffer from irritable bowel syndrome (IBS), you may have been advised to avoid caffeine (among other things). But does restricting caffeine really make a difference?  It may seem that way at first glance, but that’s not always the case for IBS sufferers.

In the world of nutrition and gut health, nothing is black-and-white!  Read on to learn my holistic perspectives and insights based on research and first-hand experiences related to all things caffeine and IBS.  Please take what you need, and leave the rest!

Disclaimer:  This is not medical or nutritional advice!  The information shared in this article is general, based on evidence-based research and my first-hand experiences as a holistic + functional dietitian in private practice and as a former IBS sufferer.  Make sure to consult with a doctor and a registered dietitian if you’re trying to navigate IBS or other gut health issues. 

What is caffeine?

Caffeine is a bitter-tasting chemical stimulant substance, which is naturally occurring in certain plant-based food/beverage constituents such as chocolate (Theobroma cacao), coffee, black tea, green tea, oolong tea, yerba mate, guarana, and yaupon.

chemical diagram of caffeine

You’ll also find caffeine in kombucha, since it’s made with black tea, and the extract of caffeine is commercially added to most types of sodas and energy drinks, as well as in workout supplements and even some diet pills.

While everyone has their own unique experience with caffeine (due to genetics and other factors), there are some overarching ways caffeine will typically impact the mind and body.

Caffeine, stress, and IBS

As a stimulant, caffeine increases central nervous system activity, which means it raises heart rate and blood pressure by stimulating the release of epinephrine and norepinephrine. (1)  These are called “catecholamines” – aka… stress hormones!

When stress hormones get released, they put our mind and body in a “fight or flight” state, which means the “rest and digest” enteric nervous system (the one responsible for healthy digestion) is shut off.  

Key takeaway:  People who have IBS worsened by stress/anxiety may be more likely to notice an uptick in IBS symptoms when consuming too much caffeine.

Caffeine, sleep, and the microbiome

If you’re familiar with my content, you’ve likely seen and heard a LOT about the gut microbiome!  And for good reason; the state of the ecosystem of microbes living in your gut has a lot to do with the state of your digestion and overall health. 

While I could say a lot more about that, I’m mentioning it here because a new study from 2022 found that caffeine-induced insomnia (over time) had a negative impact on people’s gut microbes, which could suggest an indirect correlation between caffeine and IBS. (2

In other words, too much caffeine will interfere with sleep, and sleep deprivation is bad for gut health!  

Key takeaway:  Moderating your caffeine intake (relatively speaking, so that it doesn’t interfere with the amount or the quality of sleep you get each night) is a good idea!

Caffeinated foods/beverages and the gut

Looking at more direct correlations, research attributes certain IBS symptoms like diarrhea and heartburn to consuming caffeinated beverages such as coffee and soda, which both happen to be very high in caffeine. (3)  

But is caffeine the common denominator and underlying reason for the IBS symptoms, or is it something else? 

Let’s unpack this mystery, once and for all!

Coffee and IBS

While there’s tons of independent research on coffee and IBS, the role of caffeine in this dynamic is still unclear because most research hasn’t yet isolated caffeine as an independent variable.

  • On the one hand, I’ve observed in my private functional nutrition practice that caffeinated coffee seems to worsen or amplify symptoms of diarrhea and heartburn for some but not all of my clients with IBS-D (diarrhea-predominant IBS) or IBS-M (mixed constipation and diarrhea).
  • On the other hand, I’ve also noticed over the years that caffeinated coffee seems to benefit most of my clients who are more prone to constipation (IBS-C).
    • This is one reason I’ve decided to include cold brew coffee as  a “functional food” (or beverage) in my constipation smoothie recipe, here!

The Best Smoothie for Constipation Relief - by Jenna Volpe RDN LD CLT - Whole-istic Living

What about decaf?

According to research, we know that caffeinated coffee stimulates colonic contractions and gastric acid secretions… but apparently, so does decaf, to a certain degree. (3, 4, 5

Decaf and heartburn/reflux: breaking it down

Anecdotally, decaffeinated coffee seems to be better tolerated among many of my clients with heartburn/reflux, compared to its caffeinated counterpart.

  • The bitter constituents in coffee stimulate bitter taste receptors in the gut, which trigger the release of the gastric secretions….and since caffeine is in and of itself bitter-tasting in essence, it makes sense that decaf coffee would be slightly less bitter, and thus a little less likely to trigger acid reflux.
Decaf and IBS-D: my two cents

I haven’t seen as big of a consistent difference among my clients with diarrhea who switched over to decaf from regular coffee. 

It actually varies a lot, case-by-case. 

  • For example, my clients who tested positive for a caffeine sensitivity (based on the mediator release “MRT” food sensitivity test) were more likely to experience IBS symptom relief from diarrhea when they switched to decaf, compared to those who didn’t have a caffeine sensitivity.

This study didn’t notice a big difference in the degree to which caffeinated vs decaffeinated coffee stimulated the colon.

Key takeaway:  Conflicting research and observations aside, listening to your body should always come first. If you’ve noticed that even decaffeinated coffee doesn’t sit well for you, coffee substitutes and coffee alternatives may be worth looking into!  (Read morea about decaf coffee and IBS here.)

Soda, energy drinks, and IBS

Oh boy – where do we begin?! 

100% of the time, I’ve witnessed people experience IBS relief (no matter which IBS subtype they have) just from getting soda and energy drinks out of their diet.

This stuff is carbonated (an independent trigger of IBS symptoms) – and it’s also loaded with refined sweeteners such as high fructose corn syrup or sugar or some kind of chemical alternative.  

  • High fructose corn syrup is high in FODMAPs, and this as well as other types of sweeteners in soda and energy drinks will wreak havoc on the gut microbiome when consumed regularly. (Read more on sweeteners and IBS here!)
  • Drinking sweet beverages (even if sweetened with stevia) will shut down the “Migrating Motor Complex” (MMC) which regulates gut motility, so at the very least, drinking them with meals is better than sipping on them all day between meals. (6)
  • Lastly, there are certain chemicals in diet soda and energy drinks that are extremely acidic. These chemicals (versus the caffeine) may make diet sodas and energy drinks especially irritating for those with ulcers, gastritis, and/or reflux.

Key takeaways:  I don’t believe caffeine is the primary culprit when it comes to soda and energy drinks triggering IBS symptoms.  Either way, everyone can benefit from reducing their intake of this stuff from a gut health standpoint and for better health in general. 😉

Caffeine in workout and weight loss supplements

The amount of caffeine in these types of supplements is typically very high, exceeding healthy daily amounts that one could get from drinking a normal amount of coffee or tea.

While there are no direct studies examining the impact of caffeine on gut microbes, gut pH, or colonic contractions, we know that very high levels of caffeine intake are more likely to trigger a physiological stress response and to disrupt sleep patterns. 

(There are also other risks of caffeine in supplements, which you can read more about if you’d like!)

Key takeaway: Limiting caffeine intake to levels that will not induce a stress response or insomnia will indirectly support a healthier gut. 

  • A general “industry standard” recommendation is to limit caffeine to less than 400 milligrams per day, which is about the amount of caffeine in ~12 ounces of caffeinated coffee.

Tea and IBS

Compared to coffee, even most caffeinated teas are naturally lower in caffeine by ~20-80% (depending on the type of tea).

For most people with IBS, I find that drinking caffeinated tea of any kind doesn’t seem to trigger unwanted symptoms. In fact, in many cases, green tea can actually help digestion!

On the other hand, since the literature on tea and gastroesophageal reflux disease (GERD) remains sparse and conflicting at this time, the general consensus is that people with GERD should plan to still avoid caffeinated products like tea, to be on the safe side. (7)

Listening to your body and paying attention to symptom triggers/patterns by keeping an IBS food diary can also go a long way.

Key takeaways: It’s likely safe and even beneficial for most people with IBS to drink tea in moderation, unless your body tells you otherwise. However, if you have GERD/reflux or ulcers and have been prescribed a bland diet, you should still avoid tea.

Kombucha and IBS

Okay, this one is tricky.  Kombucha (a fermented iced tea) is a naturally probiotic-rich beverage, and it’s pretty well-known for promoting gut health.  But is it for everyone?

In my practice, I’ve noticed that when it comes to kombuch and gut health, this one is totally hit-or-miss.

On the one hand, I see some people feel so much better when they add a daily bottle of probiotic-rich kombucha into their routine!  On the other hand, kombucha contains caffeine and sugar, as well as yeast and histamines.

  • While the sugar in kombucha is fermented, and the caffeine in kombucha is comparable to regular tea, this is still in some cases enough to put people over the edge from a symptom-trigger standpoint.
  • Also, if your IBS is related to a underlying overgrowth of Candida (or something similar) or mycotoxins (mold biproduct), and/or you have a histamine intolerance, kombucha isn’t going to be your ally.

Key takeaway:  Some people feel better when they drink kombucha, while others feel worse.  The yeast in kombucha (versus the caffeine) is usually what makes people feel worse.  Listen to your body and consult a qualified practitioner if you’re unsure!

Chocolate (cacao) and IBS

Last but not least: chocolate! (Aka: Theobroma cacao, or “cacao” in its unrefined state.)  

While this smooth, bitter-tasting antioxidant-packed herb contains some caffeine, much like green tea and matcha, research is suggesting that cacao is likely more of a friend than a foe for most people with IBS.  

  • Cacao is a natural source of prebiotic polyphenols, which feed and support the growth of healthy microbes in the gut. (8

There are still some people out there anecdotally who may find that chocolate aggravates their IBS symptoms, and if that’s the case, you should honor it.  But I doubt it’s directly related to the caffeine. 

If anything, people with a histamine intolerance (usually related to mycotoxin overgrowth and/or Mast Cell Activation Syndrome) might find they feel worse when eating chocolate – but that’s not because of the caffeine.

Key takeaway:  Caffeine in cacao and chocolate is likely not a culprit of IBS, but always listen to your body, and avoid chocolate if you’re prescribed a bland diet for GERD/stomach ulcers or if you have a histamine intolerance.

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The final verdict

So, is there a link between caffeine and IBS?  Yes, but it’s more likely that caffeinated coffee (versus caffeine as a stand-alone extract) is responsible for stimulating the colon and triggering diarrhea for some people with IBS-D / IBS-M.

The same goes for releasing gastric acid: caffeinated coffee, but not caffeine itself, is most likely the underlying culprit for the release of gastric juices in the gut.

The only exception is for people who have a chemical sensitivity to caffeine (which can be confirmed via looking for patterns via food-symptom journaling, and/or running an MRT food sensitivity test).

There are also no clinical studies available to confirm or deny whether a caffeine-free diet makes any kind of difference for people with IBS-D or IBS-M.

Your unique oral tolerance to caffeine from a digestive health standpoint  is likely on a spectrum and will be unique to you.  The best way to determine how caffeine impacts your own IBS symptoms is to work with a registered dietitian who can help you to look for patterns between caffeine intake and IBS symptoms via keeping an IBS food diary.

It’s also a good idea to avoid sodas, energy drinks, and diet pills from a gut health standpoint, due to their direct or indirect negative impacts on gut health.

Limiting total daily caffeine intake to no more than 400 milligrams per day max (ideally from antioxidant-rich teas and cacao or possibly coffee) is safe and beneficial for most people with IBS, as long as you’re listening to your body and honoring what it needs!

Next steps

If you’d like to stay in-the-know on all things holistic nutrition for IBS, make sure to join my weekly newsletter and download your free copy of my gut health nutrition guide: 

5 Diet Mistakes to Avoid When Healing Your Gut!

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XO – Jenna

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