Fermented Korean foods

Tea & Your Microbiome: Is tea good for your gut health?

Posted by Stephany Morgan

If you’ve been watching actual TV recently (not Netflix), odds are you’ve seen those colorful probiotic yogurt ads, they are everywhere! But what the heck is a probiotic? Why is it so important? And what about tea?

Today I’m diving into the science of probiotics and intestinal health, and what you can do to make sure your gut is healthy - especially if you’re a tea drinker. Read on to learn...


  • What is a Microbiome? What makes a healthy gut and how to maintain it
  • Why is gut health important? And how to keep it healthy!
  • Prebiotics vs. Probiotics: What are pre/probiotics, what do they do, and where can we get them?
  • Tea as a Prebiotic: How tea protects your gut health, looking especially at black, green & moringa tea
  • Kombucha as a Probiotic: Super tea or super myth?
  • Is Puerh Tea a Probiotic? Yes, there’s a fermented tea


Now, let’s get learning!


What is a Microbiome?

It’s a community of microorganisms that inhabit a certain environment. “Microbiome” is colloquially spoken of in terms of gut health: the little “bugs” that colonize our gut, or more specifically the large intestine. They predominantly reside in part of the colon called the cecum. However, we have a microbiome of bacteria throughout most of our body.

You’ve heard of “good” and “bad” bacteria, but this isn’t particularly correct. A healthy microbiome is all about relationships, and an overgrowth of any microbe can be harmful. While we do have some pathogenic “bad” bacteria, even the beneficial microbes can overgrow and become harmful.

For example, candida albicans is a fungus that is usually benign. But if it overgrows various yeast infections can occur. Same with our gut bacteria. However, they can have differing propensities for overgrowth (Pawlak, 2020).



Tea for Gut Health Healthy Breakfast Chia Seeds

 A balanced breakfast - with so many interactions between ingredients it's almost daunting!


Why is Gut Health Important?

A healthy gut is responsible for such things as immunity, sleep quality, mental health, and may contribute to diabetes, autoimmunity, and obesity.

Did you know that 90% of our serotonin is produced by gut bacteria? If your gut is unhappy, your sleep and your mental health can be impacted.

In a study with healthy mice, they sterilized their gut then gave them microbiota transplants from mice with depression. The healthy mice developed depression after the transplants! This suggests that the microbiota (that is, all microbes in the gut) was responsible (Pawlak, 2020). The same study was performed with transplants from diabetic mice to healthy mice, obese mice to healthy mice, and from mice with altered microbiota due to gastric bypass to obese mice.

Want to guess what happened? Yep! The healthy mice all developed the conditions that the donor mice had, and in the last study the obese mice experienced weight loss (Pawlak, 2020). When reverse studies were conducted, improvements in disease conditions occurred. Amazing.

Isn’t that incredible? Every week there seems to be a new study showing how important the microbiome of the body is to so many diseases, even including mental health such as depression.


So, how can you keep your gut healthy?

Processed foods and high amounts of glucose feed pathogenic bacteria. One study wanted to see how sugar impacted gut health, particularly in those with a predisposition for developing it. They based the thesis on data which suggests that western diets contribute to higher rates of Irritable Bowel Disease (IBD).

Mice predisposed to developing Colitis (a disease of the large intestine) were divided into groups and fed high amounts of sugar (glucose) for various frequencies. Glucose in the short term group didn’t cause inflammation in healthy guts, nor did it lead to severe disease, but it did significantly alter the composition of the gut microbiome. The mice in the group which received high glucose long term developed severe ulcerative colitis, whereas the ones that didn’t receive glucose developed less severe bowel disease.

They also transplanted microbiota from the sugar-treated mice into sterilized, healthy mice and the healthy mice developed a greater susceptibility to developing colitis!


Computer image of healthy gut bacteria

Image sourced from TheGoodGut; "Complete Guide to Probiotic Bacteria" 


Prebiotics vs. Probiotics: Foods for good gut health

Despite similarities in name, these are two very different things. However, both are needed. While probiotics refer to good bacteria, you can think of prebiotics as their “food”.

Before I go into the details, here are some good general guidelines for how to improve gut health:

  • Get your prebiotics. Common ones include...
    • Insoluble fiber. These are fibers that won’t dissolve during digestion like nuts and whole wheats.
    • Certain carbs. I know, carbs can be good?!?! When it comes from the right place it can be, like in oatmeal or unripe fruits!
    • Green tea
      • Need some green tea suggestions? Check out out Classic Green Tea Quartet, which is MA's bundle of some quintessential green teas
  • Eat for gut health / get your probiotics. Common probiotics include...
    • Whole foods!! (Foods that haven't been processed or refined, e.g. vegetables, fruits, fish, nuts, etc.)
    • Fermented foods (e.g. kombucha, sauerkraut, miso, kefir, yogurt with live cultures)
  • Avoid foods that are harmful to the gut (i.e. high in added fats and sugars)
  • After antibiotic therapy, be diligent about replacing your “good guys” with the fermented foods or supplements.
    • “Bad” bacteria are more antibiotic resistant. This means that when you take antibiotics, they’ll definitely wipe out your more-susceptible good bacteria while the pathogenic ones resist the treatment. Good bacteria are also harder to replace post antibiotic treatment (Pawlak, 2020).



Kimchi (Korean Fermented Cabbage)

 Kim chi is a fermented cabbage dish from South Korea, that is a delicious probiotic - and can be exceptionally spicy!


What is a Probiotic?

Probiotics are beneficial bacteria which help maintain the balance in the body between microbes. They generally refer to bacteria found in food and supplements. There’s bacteria in your food? Ewwwww! But it’s not really an “eww”! Some of the most delicious things we eat are chock full of probiotics. Here are a few examples:

  • Kimchi is made through fermentation. For the most part fermentation is one of the most common ways to develop some great funky little gut friends
  • Yogurt is one of the best and most widely accessible probiotics
  • Miso is great in soup and is filled with friendly bacteria (you guessed it - it’s also fermented, made from soybeans)
  • Pickles are another yummy fermented probiotic
  • Even some cheeses are probiotics! Cheeses like gouda and mozzarella have a bunch of good bacteria that survive the aging process.



Apples and Pears Estremoz Market

 Apples are a great example of a prebiotic - and a whole food, especially when served with two pairs of feet


What is a Prebiotic?

Prebiotics refer to indigestible fiber and other substances that promote the growth of beneficial bacteria. They are specialized plant fibers which act as fertilizer to support probiotic growth.

You can support your gut balance in two main ways: by ingesting more foods and supplements that contain live cultures, or you can eat foods with indigestible fiber (usually complex carbs) to promote the growth of the existing beneficial microbes in your gut.

Here’s where to get prebiotics:

  • Bananas are full of potassium and a ton of super vitamins that have prebiotic effects. Believe it or not unripe bananas actually have even more prebiotic effects than ripe ones!
  • Garlic contains a whole ton of fiber and antioxidants and a naturally occurring prebiotic called fructooligosaccharides (FOS)
  • Onions too have a ton of fiber and fructooligosaccharides (that's a fun word to say 10 times fast). They also contain flavonoids, an antioxidant with prebiotic effects. To learn more about flavonoids, check out our antioxidant blog on purple tea
  • Oats are super fibrous and have been shown to have prebiotic effects. While all oats are good for you, whole oats are the best prebiotics
  • Apples are rich in prebiotic fiber which has prebiotic effects. You know what they say about apples and their doctor-repellent action…



Cheerful Tea-for-One Green Teapot by MatchaAlternatives

Our Cheerful Tea-for-One Teapot is a nice way to add prebiotics to your diet (i.e. tea!)


Tea as a Prebiotic

If you’ve read any of our other blogs I’m sure you know tea can do a lot for our health, and we’ve heard about kombucha (a fermented, probiotic-rich tea - more on this below), but tea as a prebiotic? How? Tea doesn’t contain any fiber, and it isn’t exactly a carb-rich food. But, evidence suggests that some teas do have prebiotic effects. It’s because of one itty bitty organic compound: polyphenols!


Green and Black Tea for Gut Health

So what exactly are polyphenols? They are one of the many kinds of antioxidants found in Camellia sinensis, the scientific name for “true” tea, whose leaves become green, white, black, purple, and oolong tea.


If you want to learn all about polyphenols and other antioxidants in the teas you drink, read our Antioxidants Series


But guess what? Polyphenols are prebiotics, too! Studies have found that polyphenols and their subclasses increase certain beneficial bacteria species, and exert gut-protective effects via the increased production of short-chain fatty acids (which reinforce the gut lining), with strong evidence that this effect is due to prebiotic action.

The effect of polyphenols on the gut microbiota creates a chain reaction of beneficial effects in such avenues as immunity, gut metabolism, anti-inflammatory actions. Plus aiding the permeability of the intestinal tract - no point eating healthy food if your body can’t absorb the goodness! These effects are strongly attributed to the ability of beneficial bacteria to metabolize polyphenols in the same way as other prebiotic substances.

In one study, mice were fed a diet likely to cause obesity and decaffeinated green and black tea. The tea altered their gut microbiome in a way that prevented obesity. Pretty cool!

Green and black tea work together because the polyphenols from the two types behave differently in the body. Black tea polyphenols make it to the colon because they are large enough to resist absorption in the small intestine. Green tea polyphenols are highly absorbed in the small intestine. Researchers are not yet conclusive on whether green tea also plays a role directly in the gut, so more research is called for.

But we do know that green tea is beneficial because it increases the growth of certain strains of good bacteria.

Another study found that green tea altered the gut microbiome and increased amounts of Bifidobacterium, a beneficial bacteria. Tea appears to alter gut imbalances (dysbiosis) in a way that can help combat obesity and support weight loss efforts. This study was more conclusive about the gut influence of green tea.


For some yummy organic prebiotic benefits check out our Superior Osprey Gunpowder Organic Green Tea or our Sweet Jasmine Organic Green Tea


For those interested in going deeper, we did refer to “subclasses” of polyphenols earlier, and those include catechins, anthocyanins and proanthocyanidins. Sounds pretty sciency!

But happily we have written easy-to-understand articles on these antioxidants: read about catechins in The Most Common Antioxidant in Green Tea and anthocyanins in our Purple Powerhouse: The Antioxidants in Purple Tea (these are the same blue-colored ones found in blueberries, another superfood).

Moringa Powder

 Moringa powder is so green and pretty! This was taken by Elizabeth, our co-founder, when visiting central Thailand in 2019


Moringa for Gut Health

But C.sinensis is not the only tea to have shown prebiotic effects: Moringa may also aid in the protection of our lower intestines.


If you’ve been following MA, then you are definitely aware of the wonders of moringa. But if you’re new here check out our Moringa Spotlight blog!


In a study where mice were fed high-fat diets to induce obesity, levels of Bifidobacterium decreased and Lactobacilli increased. When treated with moringa, both body weight and the proper balance of the two bacteria strains were restored.

While the article doesn’t mention any prebiotic action of moringa, it does point out the beneficial effects moringa has on gut microbes. Just another amazing quality of the tea known as the “miracle tree!” 



Kombucha Jar with Mother

 A jar of kombucha, with the 'mother' or SCOBY (symbiotic culture of bacteria and yeast) on top to ferment the tea


Is Kombucha a Probiotic?

This is a tricky one! If the combined effects of green and black tea polyphenols are so good for our microbiome, then I'm pretty much obligated to mention kombucha as it is a fermented tea so you would think it's an obvious probiotic. However, the answer isn't as simple as that.

But first...what is kombucha? It is a sour, lightly carbonated drink that can be made with green or black tea, but can be made using a combination of the two. It’s made by adding yeast, bacteria, and sugar to the tea and fermenting it for usually several days (the time can vary a lot though).

If you are at all involved in the conversation around superfoods and super-drinks then you’ve definitely heard of it. There are some that swear by the health benefits of kombucha, while others remain skeptical of the fermented drink. So is kombucha a super-tea or just a health fad?

In short, kombucha is a fermented tea that is rich in probiotics, vitamin B, and antioxidants. You read earlier that fermented foods are great for probiotics, and that is true here.

Unlike most bottled tea factory processes, the fermentation process doesn’t remove the antioxidant action in green tea, and studies show that this action is evident in the liver. Kombucha reduces liver toxicity due to antioxidant action. It also appears to maintain some of the same benefits as unfermented green tea. Kombucha made with black tea also demonstrated liver-protective antioxidant effects.

However, kombucha is a can of worms. Biomedical experts argue back and forth as to whether it is healthy, not healthy, safe, not safe, does it actually have probiotic action (aerobic bacteria cultures in kombucha need oxygen, and there is almost no oxygen in our gut, making it inhospitable), but it clearly has beneficial effects according to research and they can't entirely refute the probiotic action.

It's up to debate still, not highly researched yet (but is a growing interest!), and does have antioxidant action. Then, there is the big concern about sugars in the product. Important, since why would a probiotic have so much sugar if I just pointed out that sugar feeds pathogenic bacteria and can negatively impact beneficial bacteria colonies in the gut?!? See my Note from the Herbalist below though to explain that!

So, to sum it up: Studies have observed that kombucha really may be all that, but the problem is each time we investigate the literature available, it seems we are all still unsure how.

While the actions of kombucha as a probiotic are still not fully understood, at least research is continuing to unveil its health benefits - and even if I can't definitively say it is a probiotic, I can say it contains probiotics and the research shows clear benefits from drinking it. 



Pu'erh Tea in Busan, South Korea

Drinking a Sheng Puerh in a Busan tea house, Korea during the founders' tea travels


Is Puerh Tea a Probiotic? (A fermented tea?!)

For the dedicated teaheads out there, I’m sure this was your first question, and I’ve saved it for last. :-)

Pu-erh or pu’erh is a fermented tea from the Puerh region of Yunnan, China, and it is made by burying (‘piling’) tea leaves after they have been initially withered but not yet dried or compressed. There are two types, Sheng and Shou, with Sheng being slowly fermented and Shou being quickly fermented (Spruce) (it's actually a lot more complex than this, but I'll save that for another day!).

Although the process creates a lot of fantastic bacteria...pu’erh tea is not a probiotic. The compression and drying process after the fermentation stage kills off all the bacteria, and any survivors are then killed when you pour boiling water over it at the brewing stage. A tragic story!

Interesting side note: one study found 25 toxic compounds in finished puerh tea, one of the reasons it’s traditional to discard the first brewing of any pue-rh. Note that these compounds were ‘metabolites’, a byproduct of the fermentation process. Fascinating, and a good reason for the wash stage! (Zhang)



    Stephany Morgan Tea Specialist A Note from the Herbalist...

    Gut health is an amazing topic, but there is still so much we don’t know! As you have seen much of the research so far is on mice so there is a journey to go for large safe human investigations. For example, moringa benefits our “good” bacteria, but how? (I have a theory that the fiber acts as a prebiotic, but I can’t state that as fact until there’s research available). And kombucha? Despite its apparent health benefits, we still understand very little of how it works.

    As a quick note: if you’re worried about the sugar content on kombucha labels, fear not! Labeling guidelines require companies to report the amount of sugar used in processing. The yeast ferments it, so most of it ends up converted to CO2 and ethanol (and then the bacteria metabolizes the ethanol). Levels of residual sugar depend on fermentation time, but it is less than what it began with.

    While we don’t pre-made kombucha, you can make your own kombucha at home with our teas!


    So whether your planning on making some green tea kombucha or just want some prebiotic tea, try our green tea bundle, the Classic Green Tea Quartet!



    Classic Green Tea Quartet - MA Tea Bundle; Tea Circles with Names


    Classic Green Tea Quartet

    The perfect introduction to the most famous types of Japanese & Chinese green tea. Two Japanese, two Chinese, two pures and two blends. Ideal for enjoying the world of green tea, or as a gift to your green tea loving family or friends!

    All our tea and teaware comes with free shipping in the continental US - including these bundles. Plus...every bundle sold plants one tree capturing 1 TON of carbon. Drink tea and fight climate change!


    Read more:
    Explore our Tea Science & Lifestyle blog | Subscribe to the MA Blog to save 15%!

    BONUS: Feel Good Music with Every Order!

    Every purchase you make comes with a free download of extended songs from the Dance of Life album by Norwegian composer Peder B. Hellend. 
    thirty minute track is perfect for studying, meditation, or just ambient music for a relaxing afternoon.
    A new song every month, so collect the entire album - for free!




    All of the information regarding the herbs, botanicals, minerals, vitamins, etc., is information drawn from traditional use data or academic research and should be regarded as such. If you, the reader, has a health or medical concern, please consult your healthcare professional. The information found here is not meant to diagnose, treat, prescribe or cure and has not been evaluated by the FDA. This information is for educational purposes only. 


    References & Further Reading on Probiotics & Tea

























    Pawlak, L. Microbiome: Gut-Brain Connection: Facts, Fads, and Fallacies (Laura Pawlak, Ph.D., M.S.) (March 6th, 2019) INR Seminars, Held at Double Tree in Grand Rapids, MI

    Spruce Eats https://www.thespruceeats.com/shou-vs-sheng-766448

    Zhang Y, Skaar I, Sulyok M, Liu X, Rao M, Taylor JW. The Microbiome and Metabolites in Fermented Pu-erh Tea as Revealed by High-Throughput Sequencing and Quantitative Multiplex Metabolite Analysis. PLoS One. 2016;11(6):e0157847. Published 2016 Jun 23. doi:10.1371/journal.pone.0157847 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4918958/


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      • Health Science Drag Names Inspired by this Article:
        -Sarah Tonin
        -Polly Phenal
        -Flavia Noid
        -Carmilla Sinensis
        -Mama Kim Bucha
        (Kim Chi is already taken)

        Ren Elizabeth Hirth

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