Kombucha and its potential health benefits

Kombucha is getting popular these days. The fact that it is now available off-the-shelf from major supermarkets is a sign that this fermented fizzy drink is becoming mainstream. Kombucha is a type of traditional fermented tea originated from north-eastern China (Manchuria) 1more than 2200 years ago. Traditionally, it was used as a medicine to cure digestive problems. The use of kombucha spread from China to Japan and Russia and eventually to other European countries during the second world war [1].

Commercially available kombucha products.

The growing interest worldwide in the health benefits of microbial fermented food in recent years has made this traditional drink an instant commercial success. This beverage is so popular than PepsiCo has decided to make an inroad into the business by acquiring KeVita, a major Kombucha maker in the United States, for over US$ 200 million [2].  What exactly is kombucha, and what makes it unique? Let’s explore.

What is Kombucha?

The making of kombucha – black tea plus sugar fermented with a culture of bacteria and yeasts.

Kombucha is a low-alcoholic beverage made from the fermentation of black tea and sugar with a symbiotic culture of bacteria and yeasts for around seven to ten days [3,4]. The final product contains several types of acids, including acetic, gluconic, tartaric, malic, and citric acid [5]. The acidic nature (pH ~ 4.2) gives kombucha its characteristic sour taste [6]. Kombucha also contains sugars (sucrose, glucose, and fructose), water-soluble vitamins (B1, B2, B6, B12, and C), amino acids, hydrolytic enzymes, polyphenols, minerals (manganese, iron, nickel, copper, zinc, plumb, cobalt, chromium, and cadmium), acetic acid bacteria and lactic acid bacteria, and metabolites of yeasts and bacteria [5]. A complex mixture of many nutritional and bioactive compounds, indeed.

The nutritional label of a commercially available kombucha beverage.

Potential health benefits of kombucha

Scientific studies on animals and cells have shown that kombucha possesses many useful properties for health. Firstly, it is high in antioxidants which can protect the body from oxidative stress. Secondly, kombucha can be energising due to its highly absorbable iron content (with vitamin C) which increases the oxygen-carrying capacity of the blood. Thirdly, the presence of good bacteria and bacterial metabolites in this fermented drink can modulate the immune system [4]. As such, kombucha is promoted as a health drink that has a wide range of beneficial effects on chronic diseases including diabetes mellitus, obesity, cardiovascular diseases, anaemia, liver dysfunction, neurodegenerative diseases, lung conditions, gastrointestinal disorders, and cancer [3–5]. However, these benefits are yet to be proven. There is currently a lack of controlled study on the effects of kombucha in human [3].

The kombucha SCOBY – A symbiotic mixture of bacteria and yeasts.

Is kombucha safe to consume?

It is generally safe to consume kombucha if it is produced from a clean environment. Homemade kombucha can sometimes be contaminated with harmful bacteria or toxic compounds. Besides, in patients with a depressed immune system, kombucha may also cause side-effects due to the high bacteria contents. Some reported symptoms of kombucha poisoning include allergic reactions, nausea, vomiting, and jaundice. Not surprising, there also many reported case reports of harm potentially attributed to the consumption of kombucha [1]. Hence, it is essential to consume kombucha from a reputable producer with a clean and hygienic production facility.

Beware of contemination of homemade kombucha!

Conclusion

Kombucha is a health drink made from fermented black tea. Due to its high antioxidant and probiotics content, kombucha can be potentially beneficial for many health conditions, including diabetes mellitus, obesity, cardiovascular diseases, anaemia, liver dysfunction, neurodegenerative diseases, lung conditions, gastrointestinal disorders, and cancer. However, research evidence of the benefits is still lacking. Although it is generally safe to consume, kombucha poisoning may happen if it has been contaminated. Hence, it is advisable to avoid homemade kombucha. 

Cheers!

References

[1]        R. Jayabalan, R. V Malbaša, E.S. Lončar, J.S. Vitas, M. Sathishkumar, A Review on Kombucha Tea—Microbiology, Composition, Fermentation, Beneficial Effects, Toxicity, and Tea Fungus, Compr. Rev. Food Sci. Food Saf. 13 (2014) 538–550. doi:10.1111/1541-4337.12073.

[2]        Exclusive: PepsiCo to Acquire Probiotic Drinks Maker KeVita | Fortune, (n.d.). https://fortune.com/2016/11/22/pepsico-acquires-probiotic-kevita/ (accessed December 26, 2019).

[3]        J.M. Kapp, W. Sumner, Kombucha: a systematic review of the empirical evidence of human health benefit, Ann. Epidemiol. 30 (2019) 66–70. doi:https://doi.org/10.1016/j.annepidem.2018.11.001.

[4]        I. Vīna, P. Semjonovs, R. Linde, I. Deniņa, Current Evidence on Physiological Activity and Expected Health Effects of Kombucha Fermented Beverage, J. Med. Food. 17 (2013) 179–188. doi:10.1089/jmf.2013.0031.

[5]        J. Martínez Leal, L. Valenzuela Suárez, R. Jayabalan, J. Huerta Oros, A. Escalante-Aburto, A review on health benefits of kombucha nutritional compounds and metabolites, CyTA – J. Food. 16 (2018) 390–399. doi:10.1080/19476337.2017.1410499.

[6]        S.A. Villarreal-Soto, S. Beaufort, J. Bouajila, J.-P. Souchard, P. Taillandier, Understanding Kombucha Tea Fermentation: A Review, J. Food Sci. 83 (2018) 580–588. doi:10.1111/1750-3841.14068.

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