You have heard of Kombucha, but you are not sure what it is and what it is used for?
The truth is that the popularity of fermented foods and drinks has soared in the last few years, especially with more people understanding the importance of gut health and its effect on our overall health.
Here is a detailed article about this beneficial fermented mildly fizzy drink which everyone is talking about. Learn more about its origins, how to prepare it, how to consume it, and what are its benefits, and what potential side effects on human health and wellbeing.
What exactly is Kombucha?
Kombucha is a beverage that is made of fermented sugared tea and SCOBY (symbiotic culture of bacteria and yeasts).
The yeasts and the bacteria turn the sugar in the tea into acetic acid and ethanol which gives the drink a distinct sour taste and a touch of alcohol. These are often referred to as the “mother” or “mushroom” used for making the beverage.
The bacteria and the yeast from the SCOBY can differ in types and species. The most common ones include Saccharomyces cerevisiae for the yeast and Gluconacetobacter xylinus for the bacteria which transforms the alcohols produced by the yeast into acetic and other acids. It is the living bacteria in the SCOBY which are considered healthy probiotics promoting well-balanced and healthy gut health.
Kombucha is also known as tea fungus, tea mushroom, and Manchurian mushroom or by its botanical Latin name Medusomyces gisevii.
It is a lightly effervescent, fermented, sweetened green or black tea, which is a bit alcoholic and has a sour taste.
Kombucha is commonly used as a beverage called Kombucha tea with a special culture of yeast and bacteria which gives it certain health benefits.
Often certain spices, juices or other ingredients are added to the Kombucha to enhance its taste.
Although the exact origins of Kombucha are not very clear, it is believed that it first originated in Manchuria, where the drink has been consumed traditionally, or in Russia or Eastern Europe where it has been consumed for ages too.
Today, people are home brewing Kombucha around the world. It is also produced and sold commercially by many companies too.
Many people are joining the army of Kombucha fans around the world who prefer drinking Kombucha for its acclaimed health effects including helping with arthritis, cancer, constipation, diabetes, gut health, anorexia, atherosclerosis, and even AIDS.
Unfortunately, there have been reports of some rare side effects and even a few fatalities which were most probably caused by mistakes and contamination during the home preparation of the Kombucha tea.
The history of Kombucha
As mentioned earlier, the exact history and origin of Kombucha are not really known. Manchuria is considered the most likely place of origin for this fermented drink.
It is believed that it may have originated as long as 2,000 years ago.
It has been used in parts of Eastern Russia since the 1900s, and a little later it entered the countries of Eastern Europe as well.
It was introduced and became popular in the US in the 21st century.
With alcohol content lower than 0.5%, Kombucha is not a federally regulated beverage in the US. Before 2015, certain Kombucha commercial products were found to have more alcohol in them, which led to the development of new testing methods for alcohol content.
Today, in the western world, Kombucha is often even marketed and sold as a healthier alternative to beer or other light alcoholic beverages, sold even in bars and restaurants.
Where did the name Kombucha come from?
Kombucha means “kelp tea” in Japanese. It refers to a type of kelp tea that is made from edible kelp called konbu. This is a completely different beverage from the fermented beverage known as Kombucha tea in the rest of the world.
Some people believe that the word was loaned from Japanese but has been misapplied by the English speakers who thought that Japanese fermented tea called Kocha Kinoko was called Kombucha.
According to the American Heritage Dictionary, Kombucha was “perhaps” used by English-speaking people to refer to a thick gelatinous film resulting from the fermentation of the tea which closely resembled the one produced by kelp and seaweed in Japan.
The first known use of the word Kombucha for describing this fermented beverage was in 1944.
Composition and properties of Kombucha
Its biological composition
The Kombucha culture is a symbiotic culture of yeast and bacteria (SCOBY) very much like the “mother” of vinegar. It contains one or more species of yeast and bacteria, which together create a zoogleal mat known as a “mother”.
There are various species of bacteria and yeast used for making Kombucha.
They are most commonly the Gluconacetobacter xylinus or Komagataeibacter xylinus bacteria which help ferment the alcohol produced by the yeast into acetic acid and other acids.
This process helps increase the acidic content of the drink, and reduce its alcohol (ethanol) content.
The bacteria used for preparing Kombucha require a lot of oxygen to grow and be active. They are boosted during the first four days of the fermentation process and then decrease.
This mixed symbiotic culture is lichenous and contains usnic acid, but since 2015 there have been no tests and reports confirming the standard lichens as part of the Kombucha fungal content.
Its chemical and nutritional composition
When the Kombucha is put into a sugary tea broth, the sucrose from the sugar is transformed into glucose and fructose. These then are converted into acetic and gluconic acids.
In addition, the beverage contains also amino acids, enzymes, polyphenols, and other organic acids with quantities varying in accordance with the different preparation methods.
The other components of Kombucha are ethanol, lactic acid, gluconic acid, usnic acid, Vitamins B and C.
The alcohol content in the Kombucha tea is normally less than 0.5%, but it can increase when the fermentation time is extended. The over-fermentation of the Kombucha can lead to the production of higher vinegar-like acids.
Typically, Kombucha tea has a pH of around 2.5.
How do you prepare Kombucha tea?
The usual preparation of Kombucha is with:
- Bagged or loose green or black tea – 5g
- Filtered water – 1 liter
- Sugar – 50g
- SCOBY – 24g
The tea is steeped into the boiling water for about 5 minutes, the sugar is added in order to dissolve, and allowed to cool down to about 20 degrees Celsius before the SCOBY is added.
After the yeast and bacteria are added, the drink is covered with a breathable fabric and allowed to ferment for 10-14 days. It should stay covered to keep the beverage from becoming contaminated by Drosophila fruit flies or other contaminants. The container should be left to ferment at a normal room temperature of 18-24 degrees Celsius.
When it is done, the newly formed SCOBY “daughter” which is a mushroom-like film formed on top of the surface should be removed with a small amount of tea and stored.
The rest of the drink is strained and poured into an airtight bottle or jar and some more sugar is added. It is important to add some previously prepared Kombucha tea to the mix to help lower the pH of the drink. The tea should be allowed to continue to ferment for another few days at a lower temperature of about 4 degrees Celsius.
The longer the drink with the added sugar is left, the fizzier it will be. You can also add some more spices, fruits, and flavors at this point to improve the taste of the beverage.
When Kombucha started to gain popularity in Western Europe and the US in the late 1990s some producers began making their own Kombucha drinks. But when in 2010 it was found that the alcohol levels of bottled Kombucha exceeded the allowed limits, many retailers were forced to pull out the drinks from their stores.
As a result, Kombucha manufacturers changed their recipes in order to ensure that the alcohol levels are within acceptable limits.
In 2019, some manufacturers sell “Hard Kombucha” which has higher alcohol levels.
In 2014, the sales of commercially made and bottled Kombucha reached 300 million dollars. In 2014, all of the manufacturers of Kombucha formed the Kombucha Brewers International. In 2016, PepsiCo purchased the KeVita Kombucha maker for about 200 million dollars.
The sales of fermented drinks including Kombucha rose by 37% in 2017 and are still rising.
Does Kombucha really contain alcohol?
Yes, as explained above, the yeast causes the fermentation of the tea and sugar into ethanol, so there is a low amount of alcohol in Kombucha of up to 0.5% when prepared properly.
In case the drink is left to further ferment in an airtight bottle, its alcohol content can increase quite a lot.
It is essential to talk to your doctor if you are pregnant or nursing, or taking medications that restrict the use of alcohol before consuming Kombucha.
Is Kombucha really a good source of probiotics for a healthy gut flora?
Just like other fermented foods and beverages, like yogurt, kefir, and sauerkraut, Kombucha contains live microorganisms.
It is a result of a fermentation process that causes the production of a number of different probiotic bacteria species to be produced.
In certain quantities and concentrations, these probiotics can help improve the balance of the gut microbiome and improve digestion as well as overall health.
Good bacteria can help reduce inflammations, promote good digestion, and help with weight loss.
But there are no official scientific studies done to confirm that Kombucha contains enough of these beneficial bacteria to improve gut health and to be deemed an effective probiotic.
Is Kombucha rich in antioxidants?
Antioxidants are specific substances that help fight off the free radicals which cause cell damage. Many scientists believe that the antioxidants found in foods and drinks are much more beneficial than the antioxidant supplements being offered on the market.
When it is made with green tea, Kombucha can have some antioxidant effects.
While there is no concrete scientific proof that Kombucha contains enough antioxidants to benefit human health, there have been several promising studies done that have shown its positive effect on people suffering from liver disease.
There other studies on rats that have shown that regular drinking of Kombucha can help reduce the toxicity in the liver which is caused by toxic and harmful chemicals with at least 70%.
Can Kombucha help reduce the risk of heart disease?
Heart disease is the leading cause of death on a worldwide basis.
There are some studies that show that Kombucha can help improve the two main markers of heart disease – the good HDL cholesterol and the bad LDL cholesterol in the blood, and this over a period of just 30 days of drinking the beverage.
The tea which is used for making the Kombucha, especially when it is green, also helps protect the LDL cholesterol from oxidation which too helps prevent the onset of heart disease.
There is scientific proof that people who drink green tea have a 31% lower risk of developing heart disease, which is an attribute that can be applied to Kombucha made with sweetened green tea.
Can Kombucha help manage Type II Diabetes?
Type II diabetes affects more than 300 million people worldwide. It causes high blood sugar levels, insulin resistance, and other serious health problems for those affected.
There has been a study done on diabetic rats that were given Kombucha, which was found to help slow down the digestion of carbohydrates. This reduced the blood sugar levels, prevented blood sugar peaks, and helped improve kidney and liver functions.
Kombucha which is made of green tea is more likely to have health benefits, because of the multiple health benefits from the green tea itself, especially for reducing and controlling blood sugar levels.
There is research including 300,000 subjects of which those who drank green tea on a regular basis were found to be 18% less at risk of becoming diabetics.
Can Kombucha May Help Protect Against Cancer
Cancer is one of the top leading causes of death around the world. It causes a mutation of the cells of different parts of the body and uncontrolled cell growth into malignant tumors.
According to some test-tube studies, Kombucha can help prevent the growth as well as the spread of cancerous cells thanks to its high concentration of antioxidants and polyphenols.
It is believed that polyphenols from tea help block the mutation of the cells and their growth and that they also help kill off cancer cells.
There are multiple pieces of research that show that people who drink tea regularly, especially green tea are at a lower risk of developing cancers.
But whether Kombucha has specific anti-cancer properties still remains to be confirmed by official studies.
Can Kombucha help with weight loss?
Most of the proof regarding the health benefits and the advantages of Kombucha for gut health and for weight loss is based on non-scientific claims, or on animal-based studies.
While there is still insubstantial evidence of the boost of weight loss with the help of Kombucha tea many users of the product worldwide have been swearing on the excellent results.
If Kombucha contains the proper quantities and types of probiotics, then it will definitely help promote the growth of healthy bacteria in the gut, improve digestion and help the loss of extra weight.
What are the potential side effects of drinking Kombucha?
The fermented drink has probiotics and microorganisms, so it is advisable to get your digestive system used to Kombucha gradually. Start by drinking a quarter cup and watch how your digestive system and metabolism react to it.
Some people may feel discomfort and may have bowel problems, and even become dehydrated.
If it is introduced gradually, the adverse reactions should go away by themselves in a few days.
In case you experience such mild effects after starting to introduce Kombucha into your organism, you can improve your condition by drinking more water.
If you are pregnant, nursing, have underlying health conditions, have a compromised immune system, or are taking medications, you should consult with your doctor before starting to consume Kombucha on a regular basis.
Be warned that Kombucha contains sugar, so if you have diabetes you will need to take that into account when administering your insulin.
Some reports claim that some people experienced stomach aches, dizziness, and nausea as a result of drinking too much Kombucha.
Prolonged fermentation of the drink is also not recommended because it can cause the rise of the alcohol levels and also the content of organic acids, which could be harmful to some people.
In a review from 2003 by the American Cancer Society, there were “serious side effects as well as occasional deaths associated with drinking Kombucha tea.”
Since the fermented drink is commonly made in home conditions, it is essential to take the necessary precautions to prevent contamination with pathogenic microorganisms during its preparation.
Some of the more severe adverse effects of consuming Kombucha include severe kidney and liver toxicity, and metabolic acidosis. At least one person has been known to have died after drinking Kombucha, although there is no concrete proof that it was the fermented drink that caused the death.
The acidosis can be caused by increased acidity of the drink, which is why the Kombucha brewers have been cautioned to avoid over-fermenting their products.
Bacterial and fungal contamination can happen during the brewing process as well. There are some studies that have found usnic acid which is a hepatotoxin in Kombucha, but it is not clear whether the usnic acid causes liver toxicity in some people or it is a result of another toxin which has been ingested.
Drinking Kombucha can also be harmful to people with preexisting medical conditions. This is due to the microbial content, sourcing and to potentially non-sterile packing. This is why it is not recommended for people who have compromised or weakened immune systems, or for pregnant or breastfeeding women. It is also not recommended for children under the age of four years old.
It can cause a compromise of the immune responses to the acidity of the stomach of such people.
There are also some medications that should not be combined with Kombucha due to the small alcohol content.
In a systematic review from 2019, the result concluded that Kombucha is not considered harmful when taken up to 4-oz. a day by healthy people. And that the potential risks and adverse effects are due to the low pH brew leaching heavy metals from the containers used for the fermentation, as well as by excessive consumption of the highly acidic beverage, as well as when it is consumed by people with other underlying health conditions.
Final verdict – Kombucha is healthy only when it is prepared properly
Kombucha can be purchased ready-made or can be prepared at home. However, you should prepare the probiotic tea properly.
If the Kombucha becomes over-fermented or contaminated during its preparation it can lead to serious side effects and is known to have caused several fatalities as well.
Homemade Kombucha can have a content of up to 3% alcohol, so the safer option is to get a commercially made and bottled one which has an alcohol content of up to 0.5%.
You should be warned that some brands offer “Hard Kombucha” and others are very high in sugar content, so always check the ingredient list when buying it.
Unfortunately, there is still limited scientific proof of the health benefits of Kombucha, but many people believe it is helpful for relieving certain chronic problems and is good for improving the gut microbiome.
On the other hand, drinking green tea has been proven to have multiple health benefits and also to contain antioxidants that help reduce the risk of cancer and other serious health issues.
So, in order to be certain that the Kombucha you are drinking will have more beneficial rather than possibly adverse effects, choose one from a reputable brewer, or prepare it according to all specific requirements at home.
- The health benefits of kombucha | BBC Good Food
- 8 Evidence-Based Health Benefits of Kombucha Tea
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- Bauer, Brent (July 8, 2017). “What is kombucha tea? Does it have any health benefits?”. Mayo Clinic. Retrieved 2018-09-05
- Unexplained Severe Illness Possibly Associated with Consumption of Kombucha Tea — Iowa, 1995 (Report). Morbidity and Mortality Weekly Report.
- Food Safety Assessment of Kombucha Tea Recipe and Food Safety Plan (PDF) (Report). Food Issue, Notes From the Field. British Columbia (BC) Centre for Disease Control.
- Kapp JM, Sumner W (February 2019). “Kombucha: a systematic review of the empirical evidence of human health benefit”. Ann Epidemiol.