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Kefir vs Kombucha: Which Fermented Drink Is Better?

Emma

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Medically reviewed by Kathy Shattler, MS, RDN

Kefir vs Kombucha: Which Fermented Drink Is Better?

Kefir and kombucha, over the last decade or so, have officially entered into the mainstream. They’re no longer specialty items reserved exclusively for raw vegans and health food nuts. You might even be able to find them in your local supermarket’s dairy section.

Kombucha and kefir are both wildly popular gut-friendly probiotic drinks. They’re not identical, however. And, their differences may help define which one is best for you. Kombucha should not be consumed by pregnant, breastfeeding women or children, so this is not the best choice for them; kefir is. Kefir is best for those with lactose intolerance, diabetes, or for those who need to lower their cholesterol. At the same time, kombucha tea is great for those plagued with inflammation or who need to detoxify their bodies.

How are both fermented beverages made, and where do they derive their extraordinary health properties from?

Making Kombucha vs. Making Kefir

As gross as it sounds, fermentation is the cultivation of bacterial culture in something like flour dough or vegetables submerged in sterile water. Microorganisms consume the prebiotic stock, producing new enzymes[1] that make the fermented food easier for our bodies to break down. 

These beneficial bacteria are also able to hitch a ride along with your kimchi or tempeh, joining the party already going down in your microbiome. They improve your gut health by continuing their work from within your digestive system, becoming a part of your gut flora ecosystem as a natural digestive aid.

Nearly every ancient civilization in the world eats fermented foods, and with good reason. Let’s take a quick peek into the kefir and kombucha production process for some context.

How Is Kombucha Made?

Kombucha is a byproduct of sweetened tea, usually black tea or green tea, fermented for weeks or even months at a time. Dried tea leaves are steeped briefly in sugar water before being put away for the probiotic beverage’s first round of fermentation. The bacterial culture is added through something called a SCOBY. 

“SCOBY”[2] is an acronym that stands for “symbiotic culture of bacteria and yeast.” It’s a gelatinous membrane, a “pellicle” or a “biofilm,” that floats at the top of the kombucha brew, anywhere from pale beige to deep yellow or orange. This SCOBY acts as the “mother”[3] culture for the starter tea and is retained between batches and brews.

While there is usually plenty of added sugar for the bacteria to feast upon during the fermentation process, there are no other ingredients aside from water, tea, sweetener, and a SCOBY or a commercial kombucha starter. This mix of ingredients makes kombucha tea a great low-cal beverage for a refreshing, tangy break at any time of the day. 

Bottled kombucha tea is delicious and convenient, but brewing your kombucha tea can be a lot of fun and a great project[4] to try at home. You’re able to customize your kombucha tea’s sugar content and even add flavors like ginger, lemon, coconut water, or cayenne to cut down on the added sugar.

How Is Kefir Made?

At the other end of the spectrum is milk kefir, a nourishing and sustaining probiotic beverage made from kefir grains fermented in whole milk[5]. The key to this ancient cure-all is the kefir itself, a unique blend of complex sugars, yeast overgrowth, and other beneficial bacteria. 

The kefir finds itself in an environment rich with milk proteins to break down; the sheep’s milk, goat’s milk, or cow’s milk, nourishing the microbiota that it bears perfectly. The combination results in an abundance of lactic acid, ethanol, carbon dioxide, acetoin, and acetaldehyde, culminating in the famous sour taste that traditional kefir is known for.

Milk-based kefir is creamy and delicious without being overly sweet. There is no added sugar in authentic kefir, but you’re likely to find many sweetened, flavored varieties of this milk-based treat in any grocery store. Much like making your homemade kombucha tea, it’s really easy to ferment your kefir at home.

The Health Benefits of Kombucha and Kefir

A few of the benefits of kombucha include:

  • Its ability to improve the function of your digestive system. Kombucha is an excellent source of probiotic bacteria.
  • Kombucha tea contains an abundance of vitamins, minerals, and polyphenols, plus powerful antioxidants that may help prevent neurodegenerative disease and even cancer.
  • It also contains glucuronic acid, a natural detoxifier that can help your body flush out impurities in your system, as well as the residue of hormones that have already run their course.
  • Kombucha boasts all of the ordinary benefits of black tea and green tea alone — a boost in energy, an anti-inflammatory kick, and a neuroprotective edge[6].

Kefir shares many of these benefits. A few more that might interest you include:

  • Kefir is an excellent snack for the weight conscious. It’s been shown to nourish the body without causing an undue spike[7] in blood sugar levels, although diabetics may run into kefir-related insulin issues if they overindulge—more on this in a moment.
  • Kefir stimulates[8] the immune system and might actually improve lactose tolerance by making it easier for the body to process without causing an allergic reaction.
  • Rats fed a diet supplemented with the kefir superstar Lactobacillus plantarum enjoyed lower serum cholesterol, lower LDL cholesterol, fewer triglycerides, and lower liver cholesterol. The culture was able to help them to metabolize[9] and rid themselves of the cholesterol in their bodies much more efficiently.
  • Milk kefir can actually be used topically[10] as a protective, antiseptic burn treatment.

The perks associated with the inclusion of beneficial bacteria in your diet speak for themselves.

Possible Risk Factors: Kombucha vs. Kefir

Few wellness professionals will deny the health benefits that either of these probiotic beverages brings to the table. 

As with anything, however, there are always possible risk factors to take into consideration. Some of these risks come as a result of drinking too much kombucha or kefir, but a few more insidious risk factors may surprise you.

First, the possible risk factors of drinking kombucha:

  • Kombucha contains trace amounts of alcohol[11]. Pregnant women and women who are breastfeeding should avoid drinking kombucha.
  • Trace amounts of lead have been detected in commercial kombucha during the fermentation process. While the resulting final levels in each bottle weren’t high enough to poison adult kombucha drinkers, children are advised to avoid kombucha for this reason[12].
  • As with any other caffeinated beverage, overconsumption of kombucha may lead to jitters and anxiety, especially if you’re prone to this type of reaction.
  • Kombucha is regarded as a health food beverage, but many brands do add a significant amount of sugar. If you’re diabetic or blood sugar-conscious, tread cautiously.

Some of the risk factors of kefir may include:

  • As mentioned in the 2020 survey[13] on kefir, its characteristic profile of nutrition requires animal milk to provide what it traditionally provides, often a mix of two types of milk or even several. As such, in a classical sense, kefir really cannot be veganized with something like coconut water or soy milk. A smoothie with cultured vegan yogurt might be one viable option for a vegan probiotic beverage.
  • Drinking too much kefir might be enough to throw your digestive system out of whack — an upset stomach, cramps, and even diarrhea may result as your body “over-digests” its current contents.
  • While kefir is a low glycemic index beverage, it may disproportionately affect the drinker’s blood insulin levels. It’s been shown to exist on the level of white bread[14] as far as its insulin index is concerned.

With all of that being said, you may be glad to hear: neither of these probiotics is dangerous for the average, healthy adult to consume in moderation. Bottoms up: you’re about to look and feel amazing.

Kefir vs. Kombucha: A Brief Comparison

There is no fight to be won between kombucha and kefir. Both are light, refreshing, gut-busting probiotic beverages, and we can heartily recommend either one. 

Depending on your hunger levels, your dietary preferences, or even simply your taste, one or the other will naturally emerge as the one to grab.


+ 14 sources

Health Canal avoids using tertiary references. We have strict sourcing guidelines and rely on peer-reviewed studies, academic researches from medical associations and institutions. To ensure the accuracy of articles in Health Canal, you can read more about the editorial process here

  1. Google Books. (2011). Food, Fermentation, and Micro-organisms. [online] Available at: https://books.google.com.vn/books?hl=en&lr=&id=8siFDwAAQBAJ&oi=&redir_esc=y [Accessed 25 Dec. 2021].
  2. Devanthi, P.V.P., Kho, K., Nurdiansyah, R., Briot, A., Taherzadeh, M.J. and Aslanzadeh, S. (2021). Do Kombucha Symbiotic Cultures of Bacteria and Yeast Affect Bacterial Cellulose Yield in Molasses? Journal of Fungi, [online] 7(9), p.705. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8470359/ [Accessed 25 Dec. 2021].
  3. May, A., Narayanan, S., Alcock, J., Varsani, A., Maley, C. and Aktipis, A. (2019). Kombucha: a novel model system for cooperation and conflict in a complex multi-species microbial ecosystem. PeerJ, [online] 7, p.e7565. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6730531/ [Accessed 25 Dec. 2021].
  4. paytonmin (2018). Kombucha. [online] Joshua Weissman. Available at: https://www.joshuaweissman.com/post/kombucha [Accessed 25 Dec. 2021].
  5. Farag, M.A., Jomaa, S.A., Abd El-Wahed, A. and R. El-Seedi, H. (2020). The Many Faces of Kefir Fermented Dairy Products: Quality Characteristics, Flavour Chemistry, Nutritional Value, Health Benefits, and Safety. Nutrients, [online] 12(2), p.346. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071183/ [Accessed 25 Dec. 2021].
  6. Critical Reviews in Food Science and Nutrition. (2015). Tea and Its Consumption: Benefits and Risks. [online] Available at: https://www.tandfonline.com/doi/abs/10.1080/10408398.2012.678949 [Accessed 25 Dec. 2021].
  7. Alihosseini, N. (2017). Effect of Probiotic Fermented Milk (Kefir) on Serum Level of Insulin and Homocysteine in Type 2 Diabetes Patients. Acta Endocrinologica (Bucharest), [online] 13(4), pp.431–436. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6516555/ [Accessed 25 Dec. 2021].
  8. Critical Reviews in Food Science and Nutrition. (2011). Review: Functional Properties of Kefir. [online] Available at: https://www.tandfonline.com/doi/abs/10.1080/10408390903579029 [Accessed 25 Dec. 2021].
  9. Bourrie, B.C.T., Willing, B.P. and Cotter, P.D. (2016). The Microbiota and Health Promoting Characteristics of the Fermented Beverage Kefir. Frontiers in Microbiology, [online] 7. Available at: https://www.frontiersin.org/articles/10.3389/fmicb.2016.00647/full?utm [Accessed 25 Dec. 2021].
  10. Cetik Yildiz, S., Demir, C., Cengiz, M. and Ayhanci, A. (2019). Protective properties of kefir on burn wounds of mice that were infected with S. aureus, P. auroginasa and E. coli. Cellular and Molecular Biology, [online] 65(7), p.60. Available at: https://www.cellmolbiol.org/index.php/CMB/article/view/2913 [Accessed 25 Dec. 2021].
  11. JANG, S.S., McINTYRE, L., CHAN, M., BROWN, P.N., FINLEY, J. and CHEN, S.X. (2021). Ethanol Concentration of Kombucha Teas in British Columbia, Canada. Journal of Food Protection, [online] 84(11), pp.1878–1883. Available at: https://meridian.allenpress.com/jfp/article-abstract/84/11/1878/466695/Ethanol-Concentration-of-Kombucha-Teas-in-British [Accessed 25 Dec. 2021].
  12. CyTA – Journal of Food. (2018). A review on health benefits of kombucha nutritional compounds and metabolites. [online] Available at: https://www.tandfonline.com/doi/full/10.1080/19476337.2017.1410499 [Accessed 25 Dec. 2021].
  13. Farag, M.A., Jomaa, S.A., Abd El-Wahed, A. and R. El-Seedi, H. (2020). The Many Faces of Kefir Fermented Dairy Products: Quality Characteristics, Flavour Chemistry, Nutritional Value, Health Benefits, and Safety. Nutrients, [online] 12(2), p.346. Available at: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7071183/ [Accessed 25 Dec. 2021].
  14. Kong, K.L. and Hendrich, S. (2012). Glycemic Index, Insulinemic Index, and Satiety Index of Kefir. Journal of the American College of Nutrition, [online] 31(4), pp.280–287. Available at: https://pubmed.ncbi.nlm.nih.gov/23378456/ [Accessed 25 Dec. 2021].
Emma

Medically reviewed by:

Emma Garofalo is a writer based in Pittsburgh, PA. A lover of science, art, and all things culinary, few things excite her more than the opportunity to learn about something new." It is now in the sheet in the onboarding paperwork, apologies!!

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