Kombucha tea – an exceptional probiotic

Kombucha tea – an exceptional probiotic

Kombucha is a fermented drink made from tea or a sugary infusion. The fermentation is performed with cultures of bacteria and yeasts that provide this drink with a wide range of vitamins, enzymes, minerals and essential organic acids.

What is kombucha?

Probiotic food and supplements have very peculiar ingredients: bacteria or fungi from adaptogen genera and species, that is, innocuous. Their main function consists of setting in the intestinal tract, where they will perform a highly beneficial task.

In fact, probiotics have the ability to fight against several digestive disorders, including colorectal cancer. Moreover, they strengthen the immune system, prevent urinary tract infections and even regulate the cholesterol levels. As we can see, we should take them into account due to its properties for nutrition and medicine.

In this article, we are going to deepen in a product that has recently become quite popular: kombucha. We could say that it is a probiotic drink since it is made of a series of microorganisms that are present in the final product.

Generally speaking, it is a drink that uses sweetened black tea as its main ingredient. Its flavor is acid and sweet thanks to the combination of the tea and cultures of bacteria and fungi.

Bottled kombucha


First of all, let’s emphasize the fact that kombucha is a drink, meaning that it is can help us hydrate our body. Second, we need to be aware that kombucha is a source of sugars (between 5 and 13%) due to the fermentation and sweetening of the black tea. Moreover, it also has alcohol (between 1 and 3.5 grams per liter).

This drink is usually made from black tea (although we can use green tea or other raw ingredients). Regardless, it has polyphenols, a group of exclusive compounds from the plant kingdom with powerful antioxidant effects. In the case of kombucha, this property is a little bit less strong due to the fermentation, although the final product still provides a great supply [4].

Said fermentation process needs a series of microbial species called medusomyces gisevi and it takes between 7 and 12 days. Moreover, room temperature is suitable since it does not need a special temperature.

It is a crucial biological phenomenon from the features of this drink; moreover, it allows us to obtain a more or less sweet product and more or less acid. The longer the fermentation process, the more acid and less sweet it will be.

A little bit of history about kombucha

This drink has earned many names throughout history; for instance, tea mushroom, kvass tea, Manchuria mushroom, kambotscha, Champignon de Longue Vie and fungus of immortality.

The first references about kombucha go back to the year 211 B.C, during imperial China under the rule of the Tsin dynasty. Then, it was popularly known as the “elixir of life” once they found out its spectacular effects on the body.

Historically, it was only consume in China, Russia and Germany. However, it has become quite popular all over the world in the last few decades, specially in the United States. This is mainly due to its medicinal effects, product of its regular consumption.

Making homemade kombucha

Scoby manufacturing process

Most of the time, its main ingredient is sweet black tea that undergoes a peculiar fermentation process through Scoby (acronym for Symbiotic Culture of Bacteria and Yeasts). We could describe it as a gelatinous mass that looks like a crepe due to its aspect and color and it floats on the fermentation deposit. Consequently, it receives oxygen by being in contact with the surface and triggers the fermentation by releasing its microorganisms on the tea.

Actually, it is the substance responsible for triggering the transformation from sugary tea to probiotic drink. In fact, it is similar to the production of kefir. However, instead of being immersed in the liquid, the scoby floats on the kombucha.

Even though the liquid medium that is traditionally used to make kombucha is black tea, some companies like to experiment. There are new manufacturing techniques with scoby that has nothing to do with tea but that still provides satisfactory organoleptic results. More specifically, they have used different fruits and vegetables, like carrot juice. In fact, it is possible to ferment it without adding sugar thanks to its high brix degrees (measure that determines the amount of dry matter dissolved in a liquid, mainly sugars)

Scoby strains

The scoby cultures have an irregular composition, since not all of them have the exact same microbial strains. However, these are the most determinant:

  • Acetobacter xylinoides and ketogenum are two strictly aerobic bacterial species (they only reproduce in a medium with oxygen). They are constantly present in scoby and they mainly provide acetic and gluconic acid to the culture. One of their functions consists of building the fungus.
  • Saccharomyces: it is a genus of yeasts that synthesize alcohol as a metabolite of the fermentation. They are very well known for their in the production of beer. They are the most common type of yeast in scoby and they include the species saccharomyces cerevisiae, ludwigii, apiculatus and schizosaccharomyces pombe.
  • Lactobacillus: it is a genus of aerobic bacteria that produce lactic acid that is not always present in kombucha.
  • Pediococcus: genus of anaerobic bacteria that also produce lactic acid. Their presence is also inconsistent.
  • Gluconacetobacter kombuchae: anaerobic bacteria genuine from kombucha. They feed from the nitrogen present in tea and they produce metabolites like acetic and gluconic acid.
  • Zygosaccharomyces kombuchaensis: species of yeast that is also exclusive from the scoby. It produces alcohol and an effervescent effect and, like the previous one, it contributes to the formation of the fungus.
  • Brettanomyces bruxellensis: another species of yeasts that appears inconsistently on kombucha, it provides alcohol and acetic acid to the culture.
  • We can complete the list by mentioning bacterium xylinum, gluconicum, xylinoides and katogenum, pichia fermentans and candida stellata.

Nutrient enrichment

This fermentation enriches the medium in terms of vitamins (mainly B group and C); amino acids; enzymes; and some organic acids, specially glucuronic acid (a powerful cleanser), lactic acid (it improves the digestion and blood flow); acetic acid (an antibiotic)


The benefits and properties of kombucha

Before jumping straight into the properties and benefits that make of kombucha a dietary referent, let’s not forget that is has theine. This is due to the fact that it is made with tea and said elements is a stimulant like caffeine. Therefore, those who are susceptible to stimulants should avoid taking kombucha in the evening or at any time if it has a high theine content. Otherwise, it could affect our quality of sleep.

One property of non-dairy fermented drinks that kombucha and water kefir have in common is that fact that they have more probiotic content. The reason why is because their microorganisms are in water, which considerably reduces the damage caused by the stomach acid. Consequently, many of them are able to reach the small intestine.

As a probiotic, kombucha directly enriches the microbial flora and regulates the intestinal transit. Therefore, it strengthens the immune system and it defends the organism against harmful external agents.

Main help for the organism

But its most immediate function is contributing to the proper functioning of the digestive system. This is mainly due to the acids and enzymes produced by the scoby. Precisely, the main benefits of this drink are due to its richness in organic acids. For instance, glucuronic acid plays an important role in the catabolism by improving the excretion of toxins.

But this cleansing effect is not exclusive to this acid, since malic acid can also cleanse the liver. When it comes to the derivatives of lactic strains, they are somewhat relevant to prevent cancer and improve the blood flow. In fact, two of them, acetic and usnic acid, have the ability to destroy microbes while oxalic acid stimulates the energy metabolism.

A good ally for the metabolism

Due to the abundance of group B vitamins, a vitamin complex involved in many metabolic functions such as: energy production, blood biochemistry, carbohydrate metabolism, functioning of the nervous system, ocular health… All in all, taking kombucha will improve our well being in general.

More specifically, people use it in order to buffer the stress and anxiety. Others want to relieve the symptoms of the premenstrual syndrome due to an accumulation of estrogens during that period.

Woman jumping

Detox support

The many microorganisms, acids and enzymes from kombucha support the detoxification processes of the body. Therefore, it will help to improve the functionality of the liver, which is the main organ in charge of this function. Said ability to detoxify is due to its glucuronic acid content. This is probably the most relevant substance when it comes to neutralizing and eliminating toxins and waste substances from the metabolism.

Some studies performed on laboratory animals have reported that kombucha can reduce liver toxicity up to a 70% [5].

But the liver is not the only one that benefits from the effects of glucuronic acid. In fact, the kidneys are more capable of excreting heavy metals (like lead or cadmium) and other contaminants.

Stronger immune system

Taking fermented products regularly helps to strengthen the immunity mechanisms. This is due to the fact that the immune system heavily depends on the state of the intestinal tract. That is why the microbial complex from kombucha is determinant, apart from providing antioxidant substances that work differently but with the same objective.

A powerful antioxidant

The main purpose of antioxidants consists of neutralizing the free radicals from the cell membranes. These elements are highly reactive atomic compositions that interact with molecules like DNA and proteins. Consequently, they trigger chain reactions that transform said molecules into new free radicals.

This process would go on forever if it was not for the catechins. There are plenty of these in the green tea leaves that are used to make kombucha and they can be found in the final product. Catechins belong to the phytochemical group of polyphenols, more specifically, to the flavonoids.

Mountain climbing

Lower risk of suffering diseases

Some studies [2] state that there is a statistically significant connection between taking kombucha regularly and having a lower risk of suffering cancer. According to the researchers, this effect is partly due to the polyphenol content that we mentioned previously; but it is not only due to the natural constituents of tea, rather, it is also due to some metabolites produced during the fermentation process.

Other research lines point to the fact that tea polyphenols support a wide range of functions against cancer. For instance, inhibiting gene mutations that trigger an abnormal protein synthesis that results in tumors; or blocking the proliferation of cancer cells and the invasion of surrounding tissues; preventing apoptosis or cell death and the metastasis [3].

Moreover, taking kombucha helps to fix a L-lactic acid deficiency which is quite common among cancer patients. This is due to the fact that it is one of the acids synthesized during the fermentation of tea.

Preventing arthrosis and relieving its symptoms

Another of the inherent active ingredients from kombucha is glucosamine. It is a crucial substance in the connective tissue since it helps to keep the joints on point.

Glucosamine is the precursor of the synthesis of hyaluronic acid. Said substance is a carbohydrate that prevents the connective tissue (particularly the joints) from losing lubrication and flexibility due to the passing of time. In fact, it is indispensable for the cartilage integrity and to prevent the degenerative process of arthrosis and the pain.

With antimicrobial properties

Kombucha also has antimicrobial properties mainly due to its reduced pH from its acetic acid content and other organic acids. More specifically, taking kombucha regularly is a good way of inhibiting the growth of pathogen bacteria in the digestive system. For instance, helicobacter pylori and escherichia coli which cause gastric ulcers and diarrhea, as well as salmonella typhimurium and staphylococcus.

Acetic acid also has antimycotic effect. Consequently, it will be quite useful when it comes to dealing with infections caused by fungi. In fact, this drink has proven to be quite effective against some yeast species, specially candida albicans which is responsible for vaginal infections [1].

Cardio sport clock

Lower risk of heart diseases

Some studies on laboratory animals suggest that kombucha improves the functioning of the cardiovascular system. Therefore, it lowers the risk of suffering diseases of this kind in a 30% approximately [6]. This is mainly due to its ability to reduce the LDL cholesterol and increasing the HDL [7].

In addition, it protects the cholesterol molecules against oxidation thanks to its high antioxidant content. This is an additional effect that will protect the heart and the surrounding organs.

Diabetic people can take it but with precaution

As most of us already know, diabetes increases the blood glucose levels due to a high insulin resistance. Even though most of the sugar from tea is transformed by the fermenting microorganisms, we need to clarify that this does not mean that it is sugar-free. In fact, this product could alter the glycemia from these patients.

Even though we still need to gather more concluding data, some studies suggest that taking kombucha can help diabetic people. In fact, a fermentation of 15 days could potentially contribute to reducing the glycemia.

Cosmetic uses of kombucha

Let’s leave nutrition aside for a moment. We cannot ignore the properties of kombucha for the skin as well.

It has a renowned anti-aging effect due to the regenerating power of its content in hydroxyacetic acid (AHA), vitamins and polyphenols. All these elements penetrate all the different skin layers in order to produce its effects. For instance, its most important cosmetic use is the fact that it can help to prevent the onset of wrinkles. How? By stimulating the proliferation of adipocytes in the dermis. Moreover, it adds more volume to those areas that have lost their elasticity, smoothing the skin tissue and reducing the wrinkles.

Its renowned humectant effect improves the aspect of the skin in general.

On the other hand, its microbicide effect (thanks to acetic acid among others can be used to treat acne. Its main cause is the excessive proliferation of microorganisms that trigger skin inflammation in the epidermis.

Let’s not forget that it brightens up the skin, specially the face, thanks to its high vitamin C content.

To illustrate the utility of this substance in cosmetics, these are some of the products that contain kombucha as their main ingredient: hydrating mask, kombucha water, kombucha soap, hair conditioner or a remedy for burns and wounds.

Pregnant woman cooking

Side effects and contraindications

Despite the great number of beneficial properties that we have mentioned, it would not be complete without mentioning its contraindications. We need to talk about unwanted physiological and pathological effects caused by kombucha.

One of the main worries among the experts lies in the risk that scoby can have germ species capable of triggering diseases.

It seems that one of the main elements involved is the aspergillus fungus. Although this is highly unlikely since there are barely reports regarding this issue.

There is information about cases of metabolic acidosis, respiratory insufficiency, lung edema, vascular collapse and liver toxicity. All of these take place after a constant and prolonged kombucha intake, all of them after two months. At a lower scale, we can talk about anorexia, weight loss, skin rashes and intestinal retention.

We advise being careful during lactation. Breast milk can supply substances to the baby whose metabolism is not mature enough to absorb them without any issues.

Transformation in ethanol

During the first stages of life, more or less until the age of 12, we still need to be careful. Again, this is due to the fact that the liver and kidneys are still not ready to process some of its ingredients.

The microorganisms in charge of performing the fermentation transform simple sugar in ethanol, carbon dioxide and acetic acid. Consequently, it produces alcohol (ethanol) up to a 2% of its volume. This information tends to be missing from the labels of the product, misinforming the customers.

Since it is a product that is usually made at home, there is a chance of cross-contamination. This is due to the fact that we are not careful when it comes to ensuring the sterility of both the tools and surfaces. That is why it is advisable avoiding its intake during pregnancy and lactation.

If you want to make kombucha yourself you need to be aware that it does not undergo the exhaustive sanitary controls of industrial products. Moreover, those who have a weak immune system should avoid doing so because they can easily be contaminated with germs. They are harmless in principle, but they can triggers serious infections on immunodeficient patients.

Finally, it is worth mentioning that kombucha is perfectly suitable for those who suffer lactose intolerance since it lacks this carbohydrate.

Kombucha with lemon and ginger

Making kombucha at home

All you will need is a crystal container, a cloth (extremely clean) and an rubber band. Making kombucha is extremely easy and you will need the following ingredients:

  • Scoby
  • A liter of filtered water
  • 2 tea bags (black, if possible)
  • 60 grams of white sugar
  • The starter culture, more or less half a cup (120ml) of kombucha from previous elaborations; if it is your first time, you can use apple vinegar instead.


Once the water starts boiling, put the tea bags and let them settle for fifteen minutes with the heat turn off. Then, stir the sugar until it dissolves completely and cover the recipient with the cloth until it reaches room temperature.

After that, put the tea on the crystal container and pour the scoby and the starter culture. Once again, cover it with the cloth and use the rubber band to hold it in place. You will have to leave the container in a place with stable temperature, between 20 and 26 degrees for ten days. Make sure that it is away from sunlight and with good ventilation.

If you want a sweetener kombucha you can leave it just for a week or leave it three more weeks if you want a more acid drink with barely any sugar. This can significantly alter its taste to the point that it can taste like vinegar.

Like we said at the beginning of this article, the tea is not the only raw ingredient to make kombucha. In fact, we can use coffee dregs, toasted corn infusion, coca leaf infusion or freeze-dried potato infusion. All these alternative formulations do not use the starter culture due to factors like the color, taste and smell, actually we add more scoby instead.

How to take kombucha and how to combine it

Kombucha is usually drank cold. In fact, it is mainly used as a refreshment, a reasonable intake would be around a quarter of a liter daily.

The best thing would be drinking a glass before breakfast. However, if you want to start little by little, you can drink half a glass (around 100ml) and increase the amount until you get used to it.

Kombucha flavors

Combined with water kefir

Water kefir is another fermented drink and, consequently, a probiotic.

Its preparation mainly consists of filling a recipient with water and adding the sugar, dehydrated fruit, fresh fruit or fruit juice, lemon and the kefir culture. The latter will be the one that ferments the sugars.

Kombucha and water kefir are two complementary drinks, since their composition and properties defer, but they enhance each other. Their nutrient supply justifies its use as a dietary supplement and source of hydration. However, we still need to drink water on a daily basis.

Other interesting combinations:

Cherry and ginger

In general, red fruits are frequently used to enhance the antioxidant effect of kombucha. You just have to add a few cut cherries and a little bit of grated ginger. This blend provides a very pleasant color and a spiced taste.

Peach and mint leaves

Cut a peach and macerate it with chopped mint leaves. Then, it will be ready for the kombucha.


Smash four or five strawberries and add them to the kombucha for a whole night, fermenting at room temperature.


Macerate a cinnamon branch in a recipient with kombucha for a whole night. Then, remove the cinnamon and it will be ready to drink.

Cinnamon branches

Pear and rosemary

It consists of making a rosemary infusion. Once cold, mix it with the kombucha a some pear juice.

Pineapple and anise

This one is quite interesting when it comes to taking advantage of the cleansing effects of kombucha. Mix natural pineapple juice with the kombucha and an anise infusion. The alternative is smashing some anise seeds and adding them to the pineapple juice.

Where can I buy it

You can find several kombucha brands in herbalist’s shops, parapharmacies and dietetics and ecological nutrition shops. Moreover, you can buy scoby online to make kombucha yourself.

But the most important thing is knowing what to do when it comes to choosing one kombucha or another. Above all, we need to make sure that the manufacturer has undergone the pertinent sanitary and quality controls. Therefore, it needs to be sold as a non-pasteurized drink, otherwise it would lack almost all its microorganisms and its utility as a probiotic.

Another thing we need to pay attention to is its sugar content. Let’s not forget that the purpose of drinking kombucha is not obtaining fast absorption energy.


  1. Houda Battikh, Kamel Chaieb, Amina Bakhrouf, Emna Ammar. Antibacterial and antifungal activities of black and green kombucha teas. 07 June 2012.
  2. Rasu Jayabalan, Radomir V. Malbaša, Eva S. Lončar, Jasmina S. Vitas, Muthuswamy Sathishkumar. A Review on Kombucha Tea—Microbiology, Composition, Fermentation, Beneficial Effects, Toxicity, and Tea Fungus. 21 June 2014
  3. Ann M. Bode and Zigang Dong. Signal Transduction Pathways: Targets for Green and Black Tea Polyphenols. The Hormel Institute, University of Minnesota, Austin, MN 55912, USA. Received 28 October 2002
  4. R.JayabalanaS, MarimuthubK. Changes in content of organic acids and tea polyphenols during kombucha tea fermentation. Food Chemistry. Volume 102, Issue 1, 2007, Pages 392-398
  5. Semantee Bhattacharya, Ratan Gachhui, Parames C. Hepatoprotective properties of kombucha tea against TBHP-induced oxidative stress via suppression of mitochondria dependent apoptosis. June 2011Volume 18, Issue 3, Pages 221–234
  6. Shinichi Kuriyama. The Relation between Green Tea Consumption and Cardiovascular Disease as Evidenced by Epidemiological Studies. The Journal of Nutrition, Volume 138, Issue 8, 1 August 2008, Pages 1548S–1553S. 01 August 2008
  7. Ahmed Aloulou,corresponding author Khaled Hamden, Dhouha Elloumi, Madiha Bou Ali, Khaoula Hargafi, Bassem Jaouadi, Fatma Ayadi, Abdelfattah Elfeki, and Emna Ammar. Hypoglycemic and antilipidemic properties of kombucha tea in alloxan-induced diabetic rats. BMC Complement Altern Med. 2012; 12: 63. Published online 2012 May 16

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About Alberto Ricón
Alberto Ricón
Alberto Ricón is a specialist in nutrition and food hygiene with large experience in the sector as well as being a Food Health Technician.
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