Does green tea help with digestion?

Does Green Tea Help With Digestion?

Green tea and digestion are two topics very near and dear to my heart.  If you’re among the many wondering, “does green tea help with digestion?” you’re most definitely in the right place!  Speaking as a holistic and functional dietitian, holistic nutritionist, and clinical herbalist whose entire career path started with a cup of green tea (back in 2004), I’d love to answer this question this from an evidence-based and holistic perspective.

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:  This article contains affiliate links*.  As an Amazon Associate, 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 healthy 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).  

  • As a point of reference, “healthy” bowel movements should occur daily (or almost everyday) and they should also resemble mstly “3’s” or “4’s” on the Bristol Stool Chart scale.

Bristol Stool Chart - Whole-istic Living

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)

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 health benefits, as well as green tea’s herbal energetic qualities of bitterness and astringency which can also impact digestion in a positive way.

Prebiotics

The catechins in green tea are found to be prebiotic, which means they help to feed and support the growth of healthy probiotic microbes in the gut. (3)

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 naturally 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 inflammatory 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, as I mentioned earlier, the polyphenols in green tea have prebiotic properties.  This means green tea can potentially help support and enhance digestive health at the microbial, cellular level.

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)

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.

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!  

Possible contraindications

There are always exceptions and contraindications to consider when it comes to green tea (or any tea) for digestion and 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 the debate on whether or not caffeine and IBS are compatible remains controversial, and although green tea doesn’t contain nearly as much caffeine as coffee, some people are still sensitive to the caffeine content in green tea, anecdotally.

  • If caffeine is an issue, 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)  

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. 

Steep only for 3 to 5 minutes (unlike most types of herbal tea infusions which require longer brewing times).

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.

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