Kombucha Health Benefits: State of Play

Scientific literature review: December 2019. Tom Smart, Brand Organic.

Fermented foods have been a staple of different international cultures for many years.

Kombucha, a fermented tea, has recently become popular in the United States and Europe in particular as part of the greater functional foods movement, touted for its various health benefits and riding the wave of a science-backed focus on the effect of the microbiome on human health (Kapp JM 2019).

To highlight the growth of the market, in 2016 PepsiCo acquired KeVita, then a leading North American creator of fermented probiotic and kombucha beverages, for around $200 million (PepsiCo 2016). In 2017, US sales of fermented beverages increased by 37.4% (Watson 2018), and it is now reportedly the fastest growing product worldwide in the functional beverage market (Troitino 2017).

Kombucha is made by fermenting tea (usually black, green or occasionally oolong) and sugar along with a Symbiotic Culture Of Bacteria and Yeast (SCOBY) for 7 - 10 days (Leal 2018). The mixture that follows is varied and includes compounds including sugars, tea polyphenols, various acids, fibre, ethanol, amino acids, minerals including Cu, Fe, Mn, Ni, and Zn, water-soluble vitamins such as vitamin C and several B vitamins, carbon dioxide, antibiotic substances and hydrolytic enzymes (Jayabalan R 2014). Despite this, Villarreal-Soto et al noted: ‘The microbiological composition of this beverage is quite complex and still more research is needed in order to fully understand its behaviour.’ (Villarreal- Soto SA 2018).

Kombucha consumption has associated health benefits that are widely reported in literature. These benefits are nothing new, with reports stemming from Russia at the beginning of the 20th century and during World War I that this‘Wonderdrink’ helped for headaches, gastricillnesses, and especially helped to regulate intestinal activities often disturbed by the lifestyle in the army (Dufresne C 2000).

In 1951, an important population study conducted in Russia found that daily consumption of Kombucha was correlated with an extremely high resistance to cancer (Dufresne C 2000), however their methodology was never full disclosed leading to considerable scepticism about the results. Despite so many purported benefits, modern literature involving controlled human studies are lacking (Kapp JM 2019), with only one available in modern times (Hiremath US 2002).

There is, however, considerable promise shown in non-human studies. It has been suggested that the advantages are derived from the tea and the products of fermentation (Kapp JM 2019), and that various in vitro and in vivo studies have led to the reporting of various benefits including improvement in liver and gastrointestinal functions, immune stimulation, detoxification, antioxidant, anti-tumour properties, health prophylactic and recovery effects through immune stimulation; inhibiting the development and progression of cancer, cardiovascular disease, diabetes, and neurodegenerative diseases and normal central nervous system function (Dufresne C 2000) (Leal 2018) (Baschali A 2017).

The benefits of tea drinking are much better understood, and one study showed that these effects are enhanced upon fermentation to Kombucha (Lobo RO 2017). Once fermented, the drink contains various liver detoxifiers, antioxidants, polyphenols, probiotics and free- form amino acids (Jayabalan R 2014) which are known to be advantageous for human health as they protect the human body from free radicals, thereby retarding the progress of many chronic diseases (Lobo RO 2017).

More controlled human studies are required, as are studies on the different production methods of kombucha and how they affect chemical composition of the product (Leal 2018). Different teas have a different composition and thus their effect on health varies from one to another. The same logic can therefore be applied to kombucha, which has many variables in the production process.

Kombucha does also come with some contraindications; toxicity has been suspected in a handful of cases following prolonged heavy consumption (> 400mls daily over a period of months), while young children and pregnant women in the third trimester should be given advisory warnings in a similar manner to fish or soft cheese, in part due to the low alcohol content of the drink (Leal 2018). However, these toxicity cases were reportedly due to subjects having pre-existing medical conditions, unhygienic brewing conditions or the use of improper brewing vessels, which lead to the leaching of chemicals into the product.

In summary, kombucha, a complex elixir of chemicals is reported to have various health benefits. While more human study is needed, the market for it continues to grow thanks to increased consumer awareness surrounding microbiome health.

Works Cited

Baschali A, Tsakalidou E, Kyriacou A, Karavasiloglou N, Matalas AL. 2017. "Traditional low- alcoholic and non-alcoholic fermented beverages consumed in European countries: a neglected food group." Nutrition Research Reviews 1-24.

Dufresne C, Farnworth E. 2000. "Tea, Kombucha, and health: a review." Food Research International 409-421.

Hiremath US, Vaidehi MP, Mushtari BJ. 2002. "Effect of fermented tea on the blood sugar levels of NIDDM subjects." Indian Journal of Clinical Practice 423-425.

Jayabalan R, Malbasa RV, Loncar ES, Vitas JS, Sathishkumar M. 2014. "A Review on Kombucha Tea—Microbiology, Composition, Fermentation, Beneficial Effects, Toxicity, and Tea Fungus." Comprehensive Reviews in Food Science and Food Safety 538-550.

Kapp JM, Sumner W. 2019. "Kombucha: a systematic review of the empirical evidence of human health benefit." Annals of Epidemiology 66-70.

Leal, JM. 2018. "A review on health benefits of kombucha nutritional compounds and metabolites." CyTA-Journal of Food 390- 399.

Lobo RO, Dias FO, Shenoy CK. 2017. "Kombucha for healthy living: evaluation of antioxidant potential and bioactivecompounds." International Food Research Journal 541- 546.

PepsiCo. 2016. PepsiCo Announces Definitive Agreement to Acquire KeVita, a Leader in Fermented Probiotic Beverages. November 22. https://www.pepsico.com/news/press- release/pepsico-announces-definitive- agreement-to-acquire-kevita-a-leader-in- fermented-p11222016.

Troitino, Christina. 2017. Kombucha 101: Demystifying The Past, Present And Future Of The Fermented Tea Drink. February 1. https://www.forbes.com/sites/christinatro itino/2017/02/01/kombucha-101- demystifying-the-past-present-and-future- of-the-fermented-tea- drink/#261ea4684ae2.

Villarreal-Soto SA, Beaufort S, Bouajila J, Souchard JP, Taillandier P. 2018. "Understanding Kombucha tea fermentation: a review." Journal of Food Science 580-588.

Watson, Elaine. 2018. Fermentation on fire: US retail sales of kombucha and other fermented beverages surged 37.4% in 2017. February 19. https://www.foodnavigator- usa.com/Article/2018/02/13/Fermentation -on-fire-US-retail-sales-of-kombucha-and- other-fermented-beverages-surged-37.4- in-2017#.