Traditionally green, black, or white tea (which
all come from the Camellia sinensis plant) is used to make
kombucha. Most herbal teas don’t have the nutrients needed to make the process
A sweetener is then added — usually white sugar. Other
sweeteners have been used, as well, such as honey, maple syrup, and Jerusalem
artichoke tuber extract.
Then, the mixture of tea and sweetener ferments with
the help of a symbiotic culture of bacteria and yeast (also known as a SCOBY,
or a “mother”).
A SCOBY is a thick, round, floating microbial colony
that resembles a mushroom. Even though kombucha is sometimes called
“mushroom tea,” it doesn’t contain any mushrooms.
The SCOBY is a self-perpetuating culture. This means it
multiplies itself through the process of creating kombucha tea. (New starter
colonies are sometimes called “daughters” or “babies.”)
After a period of time — anywhere between three and 30 days — the kombucha is ready to
What About the Alcohol Content of Kombucha?
During the fermentation process, the culture turns sugar
into ethanol, which is a type of alcohol. So the resulting beverage
But how much alcohol is actually in kombucha?
Compared to a standard alcoholic beverage like a 12-oz beer
(5% alcohol) or a 5-oz glass of wine (12% alcohol), not much. Kombucha
typically contains about 0.5 to (rarely) as much as 2% alcohol.
The bottled kombuchas you see in stores have to follow the
U.S. government requirements for non-alcoholic beverages. This means
unless their labels say, “21 and over,” they must contain less than 0.5%
While the alcohol content is low, it can cause problems for
some people, particularly recovering alcoholics. But for most people, it’s
not much of an issue because it’s less than 1/10 the amount typically found in
Are There Benefits to Drinking Kombucha?
Tea is a remarkably
healthy beverage. Its proven benefits range
from helping fight cancer and improving bone strength to burning fat and
protecting against cardiovascular disease.
Kombucha comes from
tea. So how does it stack up?
Studies on kombucha
have found polyphenols, acids, and vitamins, which are in
regular green and black tea. In fact, in one study, kombucha tea had more antioxidants than
Polyphenols in tea
have shown great potential in protecting against
some types of cancer. The most potent benefit of tea — both fermented and unfermented
— may be its catechin content. Catechins act as potent antioxidants and
protect against the development of disease. And many of them are abundant in kombucha.
In addition to the
beneficial components found in tea, new compounds form when you make
kombucha, which may also have favorable effects. One compound is DSL
(D-Saccharic acid-1,4-lactone). DSL has the potential to inhibit
an important enzyme that may be linked to cancer growth. More study is
needed to determine if this will also provide benefits to humans.
According to a 2008
study published in Food Chemistry, DSL is one
of many new compounds created during the fermentation process.
So kombucha likely
has many of the same stunning health benefits of
drinking tea. And it may also have some additional benefits stemming from
the DSL and other new compounds in kombucha that aren’t in unfermented tea.
What Does Science Say About the Health Claims of
Kombucha, In Particular?
If you look at the
research around kombucha and its benefits, one thing is clear: We need
There are a lot of
health claims made about kombucha, but there aren’t enough studies for us to
know if they are true or not.
We have animal
studies and some decently valid sounding theories. (I’m not a fan of animal
studies because they are often cruel, but I think they can sometimes be
useful.) But we lack scientific evidence to back up many of the health
claims about kombucha. It seems plausible that it brings some positive
health benefits. But so far, there are no published studies
on the biological effects of kombucha on humans.
While we lack
certainty, an impressive body of studies do suggest that kombucha tea could
have antimicrobial, energizing, and detoxification effects. And
it may even help prevent disease, including cancer, heart disease, and
type 2 diabetes.
Kombucha could potentially help prevent a broad
range of diseases. A 2014
review of animal studies published in
the Journal of Medicinal Food found that kombucha tea
contains properties that could help prevent many diseases, particularly
“broad-spectrum metabolic and infective disorders.” They concluded that it
may be able to help with detoxification, antioxidation,
and healthy immune function.
Kombucha could slow or kill harmful microorganisms. A 2012 study published in the Journal of Food
Chemistry reported that kombucha made from both black and green
tea had antimicrobial potential. Researchers also found that the green
fermented tea had the most antimicrobial potential. Other studies
have shown that kombucha could kill bacteria that
commonly cause food poisoning.
Kombucha may have cancer-fighting power. A 2013 study published in Biomedicine & Preventive
Nutrition showed that kombucha had remarkable potential to
inhibit angiogenesis. (Angiogenesis is the process by
which cancers lock in a steady supply of blood and become dangerous.)
Kombucha may help protect the liver. A 2009 study on some very unfortunate
rats publishedin the Journal of Microbiology and
Biotechnology revealed that kombucha tea was effective in improving
liver function and lowering the side effects of toxins.
Kombucha may reduce heart disease risk. In other studies also done on
rats, kombucha improved two markers of heart disease in as few as 30 days.
A 2015 study published in Pharmaceutical Biology found
that kombucha lowered “bad” LDL. It also led to higher levels of “good”
Kombucha may help manage diabetes. A 2012 study published in BMC Complementary
and Alternative Medicine on diabetic rats found that
kombucha slowed down the digestion of carbohydrates, reducing
blood sugar levels. Kombucha also improved liver and kidney function.
Kombucha is a rich source of probiotics. Kombucha is a fermented food and carries
a large number of probiotic bacteria that may be beneficial to your
digestive health. A 2014 study published in Food
Microbiology identified a prominent Lactobacillus population
and numerous beneficial yeast species that were abundant in kombucha.
Kombucha Side Effects, Risks, and Concerns
So what are the
potential downsides of kombucha?
Here are some things
Kombucha Contains a High Amount of Sugar
In a 2001 paper
called Sucrose and Inulin Balance During Tea Fungus Fermentation,
researchers found that almost 35% of the sugar remains
after seven days of fermentation. After 21 days, this percentage dropped to
19%. This is why kombucha tastes sweet when you drink it — even though it’s
Also, some of the
kombuchas on the market have fruit juice or sugar added after the
fermentation process. This means those batches will have more sugar.
I’m sure you don’t
need another lecture on the negative health effects of excess sugar
consumption. But some of the kombuchas at my local health store contain 14
grams of sugar in a 16-oz bottle. That’s almost as much as you’ll find in a
6-oz can of coke!
So if you’re
buying kombucha, I recommend reading the nutrition facts. And remember: If
it tastes sweet, it’s probably because it is. Aim for the lower sugar options.
Negative Effects for Some People
No two kombuchas are
exactly alike. The type of SCOBY used, length of fermentation, temperature,
humidity, containers, and ingredients can lead to wildly different outcomes.
At this point,
hundreds of millions of people have at least tasted kombucha. We know that
obvious adverse reactions, at least in the short term, are rare. But there’s a
lot we don’t know about it. Without any long-term studies on humans, it’s
difficult to know with certainty if there could be any problems that might show
up over the course of time.
We do know that
drinking kombucha has led to adverse
effects, including liver damage and
even, in at least one case, death.
Longer fermentation produces high levels of acids that may posepotential
risks when consumed by vulnerable populations, such as people with compromised
immune systems or those with HIV.
We also know that
some people have reported experiencing nausea and dizziness,
as well as allergic reactions and headaches.
Does this mean
kombucha is dangerous for you? Not necessarily. It means that we don’t know with certainty
because modern production methods (and scale) are relatively unprecedented. So
as with many things in life, it’s important to listen to your own body and see
what you notice.
And if you’re
pregnant or lactating, you should probably steer clear of it altogether. A 2018
report published in the Journal of Primary Health
Care recommends that pregnant and lactating women should avoid
Should You Try Making Kombucha At Home?