Does green tea help with digestion?

Does Green Tea Help With Digestion?

If you’re among the many who have been wondering, “does green tea help with digestion?” you’re most definitely in the right place!  

Speaking as a holistic and functional dietitian, gut health nutritionist, and clinical herbalist, I’m confident your burning questions about the potential benefits of green tea for digestion will be covered in this article.  (If I missed anything, please feel free to let me know and I’ll make sure to update this post!) 

Green tea and digestion are clearly two topics near and dear to my heart for multiple reasons.  While I could talk for weeks on end about green tea and digestion, I’ll keep it relatively short and sweet for your sake. 😉 

Green tea, digestion, and my career path – a quick backstory

Green tea was the initial catalyst which kickstarted my entire career path as a holistic nutrition professional, back in 2004. (This was way before green tea became popular as a “superfood” in the media.)

  • Long story short: a serendipitous encounter led me to learn about the many benefits of antioxidants in green tea, which then ignited a deep understanding of and appreciation for the power of prevention and “food as medicine” at a young age. 
    • From that day forward, I’ve aspired to continuously study and learn as much as possible about tea, herbs, nutrition, and holistic health.  Becoming a registered dietitian and licensed nutritionist were the very clear next steps on my journey at that time!

My interest and expertise in digestive health and functional nutrition began in 2009-2010 – not by choice.  (Let’s be honest – nobody ever just wakes up one day and decides to be a digestive health dietitian or gut health nutritionist!) 😉 

  • Around that time,I started developing some relatively sudden-onset digestive issues, hormonal havoc, subsequent nutritional deficiencies, and immune imbalances as a young clinician. 

On a more positive note, dealing with and eventually healing from those health issues was what kickstarted part two of my journey to becoming a holistic dietitian specializing in digestive health and learning exponentially more about functional nutrition.

(While green tea did not play a direct role in managing or healing my digestive issues, since herbs alone are rarely if ever enough to combat long-standing gut imbalances, drinking green tea before and throughout my entire journey certainly didn’t hurt!)

  • If you’d like to learn more about my personal first-hand experiences and insights with green tea and digestion, feel free to check out the full backstory here.

Now without any further ado, let’s get your burning questions about green tea and digestion answered. 😀

Disclaimer

The information shared in this article is generalized and educational. It’s not customized and it’s not medical advice! Always consult a doctor, dietitian, and other members of your treatment team as needed when navigating a medical condition.

Affiliate disclosure

I’m an affiliate for products that I love and use often. If you make a purchase using any of my affiliate* links in this article, I will make a small commission at no extra cost to you!

What is green tea?

Green tea is a type of caffeinated tea which is made from the dried leaves from a plant species called Camelia sinensis.  

  • Camelia sinensis originates in China and now also grows in other various parts of the world.  
    • Camelia sinensis also happens to be the same plant that black tea, oolong tea, and white tea come from.  The key difference is how each type of tea leaves are harvested and processed.

According to Teatulia, an organic online tea shop, what makes green tea leaves unique is that once they’re harvested from the Camelia sinensis plant, the leaves are “then quickly heated—by pan firing or steaming—and dried to prevent too much oxidation from occurring that would turn the green leaves brown and alter their fresh-picked flavor.”

Before we dive into the multitude of benefits green tea has to offer us, let’s first zoom in on digestion, so you have some context!

What is digestion?

“Digestion” (in a nutshell) is the process of chewing, swallowing, and slowly breaking down food in the gut, until the nutrients are small enough to get properly extracted and absorbed into the body. 

  • From there, our body uses nutrients such as carbs, proteins, fats, and micronutrients (vitamins, minerals, and antioxidants) for millions of different purposes!

A healthy digestive system is able to extract what it needs from food, and eliminate the rest as waste (aka poop).

Specific factors like the state of the gut, the liver, the gallbladder, the pancreas (our 4 main digestive organs) as well as the nervous system, how well we chew our food (or don’t), and the gut microbiome can all make a big difference in digestion – for better or worse, depending on what’s going on!

What is the gut microbiome?

The gut microbiome is an ecosystem of microbes (bacteria, yeast/fungi and viruses) which live in the gut and often help us to digest our food. 

Each individual person’s microbiome is as unique as their fingerprint, and the amount of microbes living in each person’s gut is at least equal to if not exceeding the total number of human cells per person! (1)

Most of these microbes are good, but some are not so good.

  • The “good” microbes are often referred to as “probiotics”, while the harmful bacteria are often referred to as “dysbiotic” or “pathogenic” microbes.

Why care about digestion and the gut microbiome?

To say the state of our digestion and gut microbiome are pretty important is an understatement!

Studies have linked digestion, gut health and the microbiome directly to the state of our mental health, brain function, immunity, detoxification, hormonal regulation, skin health, energy metabolism, and more. (2)

…Call me biased, but I believe maintaining healthy digestion and happy gut microbes are key components of living your best life!

How does green tea aid digestion?

While the benefits of green tea extend far beyond just the gut, in this article we’re going to zero in on green tea specifically for digestion and gut health.

Antioxidants, polyphenols, flavonoids, and catechins

Each of the benefits of green tea I’m about to share can be attributed to its naturally high quantity and quality of antioxidants, which  are a class of natural substances from food and herbs, which fight inflammation and protect cells from oxidation and damage.

  • You may have also heard antioxidants being referred to as “polyphenols”, “flavonols” or “catechins” (sub-types of antioxidants).
    • The four main types of catechin derivatives in green tea are epicatechin, epigallocatechin, epicatechin gallate and epigallocatechin gallate (“EGCG”).  I dare you to try saying each of those 10x fast! 😀

The catechins in green tea play a major role in each of green tea’s known clinical benefits (3) as well as green tea’s herbal energetic qualities of bitterness and astringency which can also impact digestion in a positive way.

(“Herbal energetics” is referring to the specific actions that an herb has on the tissue states of the body, clinically speaking.)

Green tea taste & energetics: bitter is better!

From an herbal energetic standpoint, green tea is very bitter-tasting,

This is significant because we know that bitter herbs seem to help to stimulate the release of gastric juices and certain digestive hormones in the gut, via our bitter taste receptors. (4)

Green tea is astringent to gut tissue

Green tea is also astringent, which indicates it is drying, toning and tightening to tissues in the body (such as the gut and the skin). 

  • Astringent herbs (clinically speaking) are generally beneficial and balancing for loose or “leaky” tissues in the body, such as in cases of leaky gut syndrome and/or irritable bowel disease.  
    • However, astringent herbs aren’t always ideal for those who are constipated and already dealing with tightness and/or dryness in the intestines/colon!  Work with a clinical herbalist to determine whether or not green tea is an herbal ally for you, if you’re unsure.

Green tea helps support a healthier gut microbiome

While the exact mechanisms aren’t yet well understood, it’s been hypothesized that green tea may serve as a prebiotic.  Either way, it’s clear that green tea supports a healthier microbiome in multiple ways!  

Green tea helps boost and feed “good” probiotic microbes in the gut

  • A recent 2021 study from the “Molecules” journal revealed that the catechins in green tea seem to significantly stimulate and support the growth of healthy probiotic microbes in the gut. (5)  
  • In just one week, green tea extract was shown in a 2019 study by Scientific reports to modulate the gut microbiome for the better by encouraging the growth of healthy probiotic strains including Bifidobacteria and Lactobacillus in mice. (6)
  • Another study concluded that drinking green tea alters the microbiome in ways that seem to significantly reduce the occurrence of “carcinogenesis” (the process of cancer growth) in the body. (7)

Green tea helps reduce and control “bad” dysbiotic microbes in the gut

Not only does green tea help modulate probiotic “good” microbes in the gut for the better, but it’s also been shown to be helpful for people with “dysbiosis”,

(Dysbiosis is an imbalance of health vs. unhealthy gut microbes, which is a common underlying root cause of IBS, leaky gut, and many other chronic health issues). 

  • A 2019 Nutrients study concluded that drinking green tea regularly (~4 to 5 cups daily) has helped to keep the growth of certain harmful, dysbiotic microbes under control. (8
  • The catechins in green tea seem to have an antimicrobial effect on “bad” bacteria, according to a 2014 study via Frontiers in microbiology. (9)

Green tea catechins help reduce inflammation

While green tea’s role on the gut microbes in and of itself is gold-medal-worthy (in my opinion), the benefits of green tea for digestion and gut health don’t stop there!

The catechins in green tea are shown to demonstrate anti-inflammatory action on the intestinal cells (10), and they also support a healthier gut barrier integrity. (11)  

This is potentially groundbreaking for people suffering from leaky gut syndrome, a condition in which the barrier of the gut is weakened and compromised, letting unwanted substances “leak” into the bloodstream due to poor boundaries.

Green tea catechins help combat cancer 

Green tea is well-known to help prevent multiple types of cancer, including cancers in the gut!

  • In a Molecular nutrition & food research study from 2018, 12 healthy participants drank green tea for only two weeks and experienced significant changes in their gut microbiome, which “reduced” certain cellular pathways known to contribute to the development of colorectal cancer. (7)
  • A population-based case-control study conducted in Shanghai, China from 1991 to 1993 observed and evaluated green tea drinking habits among ~700 participants, and concluded that green tea can significantly disrupt gastric carcinogenesis (stomach cancer), even at the intermediate and later stages. (12

On that note, it’s important to keep in mind (as always) that green tea, even as an anti-inflammatory, cancer-fighting, microbiome-helping gut ally, like all other “superfoods” and herbs, is still not for everyone!  

Contraindications of green tea for digestion 

There are always exceptions and contraindications to consider when it comes to green tea (or any tea) for gut health.  

For example, green tea contains significant amounts of caffeine, tannins, goitrogens, fluoride, and it can even deplete folate levels when consumed in excess.

Make sure to read each of the following contraindications if you’re pregnant/nursing or you have a medical condition of any kind!

Caffeine

Green tea contains caffeine, which is known to stimulate the nervous system, heart, and colon. (14

While green tea only has about a third of the caffeine of a cup of coffee, people who react to caffeine (especially those with a tendency towards anxiety, diarrhea, or insomnia) should avoid or limit green tea depending on their caffeine thresholds.

Caffeine is also acidic, which could erode the gut lining and trigger flares for people suffering from heartburn, reflux (GERD), gastritis, Crohn’s disease, or ulcers of any kind.

  • You may be able to reduce unwanted side effects of caffeine from green tea by opting for decaffeinated green tea, or by drinking your green tea with food (to “buffer” the caffeine) versus drinking it on an empty stomach.
    • You can also make your own decaffeinated green tea by simply steeping the tea leaves for one minute in hot water, discarding that initial brew, (since most of the caffeine is extracted in the first minute), and then re-steeping the leaves for three to five minutes.

Tannins 

Green tea is high in substances called tannins which (like catechins) are also bitter.  However unlike catechins, tannins are “anti-nutrient-like” substances also found in coffee, other types of tea, chocolate, and wine.

  • Tannins, like oxalates and phytic acid (other types of “anti-nutrients”) are known to bind and block certain minerals like iron and zinc from getting properly absorbed into the body.   

People with iron deficiency anemia or a zinc deficiency should tread lightly with green tea, limiting it to no more than a few times per week and taking it a few hours apart from mineral supplements.

Fluoride and goitrogens

The Camelia sinensis plant (where green tea comes from) is known to be very high in fluoride, containing anywhere from 100 to 200 milligrams per kilogram of weight. Wowzah! (14

While fluoride in small amounts is healthy and necessary for bones and teeth, larger amounts of fluoride are not great for the thyroid.

Fluoride is also a goitrogen, meaning it can potentially interfere with iodine absorption. 

While some clinical studies didn’t find that fluoride consumption significantly impacts the thyroid as long as iodine intake is optimal in the diet (15), other studies have observed correlations with higher fluoride intake and lower thyroid function. 

  • For example, a Canadian study from 2018 observed that adults with higher urinary fluoride levels were found to also have iodine deficiencies and higher TSH levels, indicating lower thyroid function. (16)  

While the jury’s still out, just to be on the safe side, people with goiter or thyroid conditions should consider working with a holistic and functional dietitian and/or a clinical herbalist to find custom, alternative ways to support digestion with herbs!

Folate depletion

Green tea has a tendency to reduce folate absorption into the body. (17)

For this reason, anyone who is trying to become pregnant or who is currently pregnant should avoid matcha completely to reduce the likelihood of developing a folate deficiency which can lead to neural tube defects in newborns.

People with the MTHFR gene mutation also have a tendency towards folate deficiency, so they should keep their intake of matcha moderate and supplement with folate as needed.

How to maximize the benefits of green tea for digestion

While most studies are focused on loose-leaf green tea and/or green tea extract, below are my first-hand recommendations on how to get the most “bang for your buck” when it comes to green tea for better digestion!

  1. Opt for organic 
  2. Go with loose-leaf
  3. Brew with filtered water

Opt for organic

In clinical herbalism we’re often reminded that less pesticides are always better than more, when it comes to herbal tea infusions. (Chemical pesticides may help to increase the yield of tea, but this is often at the consumer’s expense.)

  • A 2014 study from Food chemistry used gas chromatography to measure the transfer of pesticide residues from green tea, and found that four of the eight pesticides did get infused into the cup of tea.  
    • Researchers also noted that longer steeping times (beyond 4-5 minutes) and hotter water temperatures (over 140 degrees Fahrenheit, or over 60 degrees Celsius) seem to result in an increased extraction of certain pesticides including azoxystrobin, fenitrothion, and difenoconazole. (18

Go with loose-leaf vs commercial tea bags

The benefits you read about from all the clinical studies are specific to loose leaf tea, and or extracts of loose leaf tea. 

That being said, unfortunately nowadays, traditional green tea is now being exploited and commercialized by the food industry!

  • The commercial tea bags being sold in supermarkets have been found to contain certain heavy metal contaminants (such as aluminum and lead) as well as other contaminants such as nylon, polyethylene terephthalate, and chlorine (19, 20).  

Brew your tea with filtered water or spring water 

While green tea has been proven to have positive anticancer effects on colorectal tumors, unfortunately chlorinated water seems to have a pro-cancer effect on colorectal tumors, since chlorine consumed above certain thresholds can and will negatively impact the microbiome. (21)

Not all tap water is going to contain the same amount of chlorine, but if you’re planning on drinking green tea regularly, opting for filtered water and/or spring water (both which do not contain chlorine) would be my recommendation.

  • In my household, we use a Berkey filter* because it also removes fluoride and other heavy metal contaminants beyond what a basic water filter can do.  
    • But at the very least, all water filters do remove most of the chlorine from tap water!

How to make a loose-leaf green tea infusion

To make a loose-leaf green tea infusion, steep one to two teaspoons of organic dried green tea leaves in about 12 to 16 ounces of hot filtered water.

Green tea for digestion: how much is enough vs. too much?

One study mentioned that drinking four to five cups a day of green tea seems to be the “sweet spot” when it comes to increasing levels of good microbes such as Bifidobacterium in the colon. (8

In my experience, three to four cups of green tea most days seems to be enough to reap the digestive benefits of green tea, provided it’s a good fit, and provided it’s being taken alongside other medical and functional nutrition interventions as needed.

  • Friendly reminder: drinking green tea once in a while is fun and harmless, but once in a while is not what will move the needle forward if you’re going for the health benefits!

Can you add milk to green tea?

While I was taught anecdotally that some of the proteins in cow’s milk can potentially bind green tea’s catechins, studies have not yet found this to be true. (22, 23)

  • Either way, I personally opt not to add milk to my green tea infusions.  
  • Since so many people with digestive issues happen to be lactose intolerant, it may be counterintuitive to add milk or cream to your digestive elixir.  But you do you! 😉

Herbs for digestion and leaky gut: additional resources

If you’d like to learn more about the different ways herbs can benefit digestion and gut health, make sure to also check out the following articles:

So, does green tea help with digestion? Final verdict

From serving as a digestive bitter and astringent tonic to supporting healthier gut microbes, to toning and tightening a “leaky” gut lining and reducing inflammation in the intestines, to preventing multiple types of gastrointestinal cancer – it’s safe to say green tea does indeed help with digestion in many ways!

Consistency is key – drinking green tea once in a while is not enough to serve as a therapeutic dose, as demonstrated in studies which suggest 3 to 5 cups of green tea most days to leverage the power of its antioxidant catechins.

Not all green tea is created equal; green tea is most likely to support digestion when made as an organic, loose-leaf tea brewed in filtered water or spring water to reduce and minimize exposure to pesticides, contaminants, and heavy metals.

Green tea can make a great ally, but it should never replace medical and functional nutrition interventions on your gut-healing journey.  Despite the overwhelming research confirming the multitude of digestive benefits of green tea, drinking green tea (yup, even the recommended three to five cups of organic loose leaf brew everyday) is still not a “magic bullet” solution to digestive issues (as I’ve learned and experienced first-hand).  

People who are pregnant, nursing, sensitive to caffeine, and/or people with thyroid conditions should consult their doctor and holistic healthcare team before adding green tea into their routines. 

For those who may not be the best candidate for drinking green tea, it could be helpful to consult a holistic and functional dietitian and/or a clinical herbalist to find other herbal alternatives.

References

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  2. Zhang, Yu-Jie et al. “Impacts of gut bacteria on human health and diseases.” International journal of molecular sciences vol. 16,4 7493-519. 2 Apr. 2015, doi:10.3390/ijms16047493
  3. Musial, Claudia et al. “Beneficial Properties of Green Tea Catechins.” International journal of molecular sciences vol. 21,5 1744. 4 Mar. 2020, doi:10.3390/ijms21051744
  4. Sternini, Catia. “Taste receptors in the gastrointestinal tract. IV. Functional implications of bitter taste receptors in gastrointestinal chemosensing.” American journal of physiology. Gastrointestinal and liver physiology vol. 292,2 (2007): G457-61. doi:10.1152/ajpgi.00411.2006
  5. Pérez-Burillo, Sergio et al. “Green Tea and Its Relation to Human Gut Microbiome.” Molecules (Basel, Switzerland) vol. 26,13 3907. 26 Jun. 2021, doi:10.3390/molecules26133907
  6. Jung, Eun Sung et al. “Seven-day Green Tea Supplementation Revamps Gut Microbiome and Caecum/Skin Metabolome in Mice from Stress.” Scientific reports vol. 9,1 18418. 5 Dec. 2019, doi:10.1038/s41598-019-54808-5
  7. Yuan, Xiaojie et al. “Green Tea Liquid Consumption Alters the Human Intestinal and Oral Microbiome.” Molecular nutrition & food research vol. 62,12 (2018): e1800178. doi:10.1002/mnfr.201800178
  8. Bond, Timothy, and Emma Derbyshire. “Tea Compounds and the Gut Microbiome: Findings from Trials and Mechanistic Studies.” Nutrients vol. 11,10 2364. 3 Oct. 2019, doi:10.3390/nu11102364
  9. Reygaert, Wanda C. “The antimicrobial possibilities of green tea.” Frontiers in microbiology vol. 5 434. 20 Aug. 2014, doi:10.3389/fmicb.2014.00434
  10. Hodges, Joanna K et al. “Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults.” Contemporary clinical trials communications vol. 17 100495. 20 Nov. 2019, doi:10.1016/j.conctc.2019.100495
  11. Hodges, Joanna K et al. “Intestinal-level anti-inflammatory bioactivities of catechin-rich green tea: Rationale, design, and methods of a double-blind, randomized, placebo-controlled crossover trial in metabolic syndrome and healthy adults.” Contemporary clinical trials communications vol. 17 100495. 20 Nov. 2019, doi:10.1016/j.conctc.2019.100495
  12. Yu, G P et al. “Green-tea consumption and risk of stomach cancer: a population-based case-control study in Shanghai, China.” Cancer causes & control : CCC vol. 6,6 (1995): 532-8. doi:10.1007/BF00054162
  13. Wang, Xinzhou et al. “Tea Polyphenols: A Natural Antioxidant Regulates Gut Flora to Protect the Intestinal Mucosa and Prevent Chronic Diseases.” Antioxidants (Basel, Switzerland) vol. 11,2 253. 28 Jan. 2022, doi:10.3390/antiox11020253
  14. Abo, M et al. “Effects of caffeine on gastrointestinal myoelectric activity and colonic spike activity in dogs.” Scandinavian journal of gastroenterology vol. 35,4 (2000): 368-74. doi:10.1080/003655200750023921 
  15. Shaik, Naseemoon et al. “Fluoride ingestion and thyroid function in children resident of naturally fluoridated areas – An observational study.” Journal of clinical and experimental dentistry vol. 11,10 e883-e889. 1 Oct. 2019, doi:10.4317/jced.55812
  16. Maleki, Afshin et al. “Daily Fluoride Intake from Iranian Green Tea: Evaluation of Various Flavorings on Fluoride Release.” Environmental health insights vol. 10 59-63. 28 Mar. 2016, doi:10.4137/EHI.S38511
  17. Shiraishi, Mie et al. “Association between the serum folate levels and tea consumption during pregnancy.” Bioscience trends vol. 4,5 (2010): 225-30.
  18. Cho, Soon-Kil et al. “Simultaneous multi-determination and transfer of eight pesticide residues from green tea leaves to infusion using gas chromatography.” Food chemistry vol. 165 (2014): 532-9. doi:10.1016/j.foodchem.2014.05.145
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