Prepared by: Assoc. Prof. Dr. Nurul Shazini Ramli

Department of Food Science

Faculty of Food Science and Technology, Universiti Putra Malaysia (UPM)

Introduction

In recent years, consumers worldwide have become increasingly health-conscious, shifting away from sugar-sweetened beverages (SSBs) such as carbonated soft drinks, energy drinks, and sweetened fruit juices. These conventional drinks have been associated with obesity, type 2 diabetes, dental erosion, and cardiovascular disease. In their place, functional fermented beverages like kombucha are gaining popularity not only for their distinctive tangy, slightly gassy taste but also for the growing body of scientific evidence supporting their health benefits.

What Is Kombucha?

Kombucha is an ancient Asian fermented tea beverage with a history spanning more than 2,000 years. Today, it is recognized globally as a unique functional drink with wide-ranging therapeutic properties including antimicrobial, antioxidant, anti-cancer, antidiabetic, and liver-protective effects.

Kombucha is prepared by fermenting sweetened black tea (or green, oolong, or other teas) using a Symbiotic Culture of Bacteria and Yeast, commonly known as SCOBY. Typical preparation involves dissolving approximately 5 g of tea and sugar in 1 litre of water, then adding the SCOBY starter culture. Under aerobic conditions, fermentation proceeds for 7 to 10 days, during which the SCOBY metabolizes the sugars and produces a complex mixture of beneficial compounds (Figure 1). The resulting beverage is slightly sweet, sour, and mildly carbonated, with a pH of approximately 3 to 3.5. Its sensory profile is refreshing and pleasantly acidic makes it an appealing alternative to conventional soft drinks, particularly for health-aware consumers.

Figure 1: Schematic diagram of the ingredients and brewing procedure for unflavoured kombucha

Chemical Composition of Kombucha

The health-promoting properties of kombucha are closely tied to its rich and diverse chemical composition, which includes:

• Organic Acids: Acetic, lactic, and gluconic acids are the dominant organic acids and contribute to kombucha's characteristic acidity and antimicrobial activity. Glucuronic acid a particularly noteworthy componentcan bind to toxins in the liver and facilitate their excretion through the kidneys and intestines.
• Vitamins: Kombucha contains B-complex vitamins (B1, B2, B3, B6, and B12) and vitamin C. The presence of vitamin B12, which is absent from many plant-based diets, is of nutritional significance. Vitamin C levels also increase during fermentation.
• Amino Acids: Both essential and non-essential amino acids are present, including lysine, valine, leucine, isoleucine, tyrosine, and phenylalanine. These free amino acids are involved in various health-promoting biological processes.
• Enzymes: Kombucha contains amylase, lactase, and invertase (beta-fructofuranosidase), which assist in the breakdown of sugars and improve digestion efficiency.
• Polyphenols and Antioxidants: The fermentation process enhances the polyphenol content of kombucha, making it a stronger antioxidant than unfermented black or green tea. It also contains vitamins C and E, and beta-carotene.

 

Health Benefits of Kombucha

Scientific research has documented many health benefits associated with kombucha consumption:

1. Antioxidant Protection

The fermentation process generates low-molecular-weight antioxidant compounds from polyphenols. Regular consumption of kombucha has been suggested to help combat chronic diseases caused by oxidative stress, such as cardiovascular disease and neurodegeneration.

2. Antimicrobial Activity

Kombucha exhibits broad-spectrum antimicrobial activity against pathogenic bacteria including Helicobacter pylori (responsible for gastric ulcers), Escherichia coli, Staphylococcus spp., Salmonella spp., and Shigella. This effect is primarily attributed to its organic acid content and low pH, as well as metabolites produced by SCOBY.

3. Probiotic and Prebiotic Properties

Kombucha functions as both a probiotic and prebiotic beverage. The SCOBY contains beneficial microorganisms from genera such as Lactobacillus, Bifidobacterium, Gluconobacter, Acetobacter, and Saccharomyces. These microorganisms colonise and support the gut microbiota, improving digestion, boosting the immune system, and potentially reducing anxiety and depression.

4. Liver Protection and Detoxification

Glucuronic acid in kombucha is a potent detoxifying agent. It binds to toxins — including heavy metals, bilirubin, and excess steroid hormones — and enhances their elimination via the kidneys and intestines. Studies in animal models have shown that kombucha protects the liver against damage induced by carbon tetrachloride, aflatoxin B1, and acetaminophen.

5. Anti-Cancer Properties

Tea polyphenols in kombucha have demonstrated the ability to inhibit cancer cell proliferation, induce apoptosis, and suppress tumour metastasis. Compounds such as lactic acid, glucuronic acid, gluconic acid, and vitamin C are associated with reduced cancer risk. Kombucha is not a cure for cancer, but its bioactive compounds may contribute to cancer prevention.

6. Antidiabetic Effects

With a very low sugar content of approximately 4 to 5% (as most sugars are metabolised during fermentation), kombucha is a suitable beverage for individuals managing diabetes. Research has shown that kombucha inhibits alpha-amylase activity and suppresses elevated blood glucose levels, making it a beneficial dietary addition for people with type 2 diabetes.

7. Digestive Health

Kombucha improves digestion and supports gastrointestinal health. Its butyric acid (produced by yeasts) helps protect intestinal cell membranes, while lactic acid improves blood circulation and prevents constipation. Regular consumption — approximately 250 ml per day for two months — has been reported to noticeably improve digestive function.

8. Skin Health

Kombucha's fermentation produces anti-ageing active agents including lactic acid, vitamin B3, and vitamin C, which stimulate collagen and hyaluronic acid synthesis. Fermented kombucha has been shown to inhibit collagenase and elastase — enzymes responsible for skin ageing — supporting its potential application in both oral and topical skincare.

Conclusion

Kombucha is far more than a trendy health drink. It is a scientifically validated functional beverage with a remarkable profile of bioactive compounds and therapeutic properties. As a natural, low-sugar, probiotic-rich alternative to conventional sweetened drinks, it aligns well with current dietary guidelines encouraging reduced sugar intake and increased consumption of fermented foods. Whether consumed for gut health, antioxidant protection, detoxification, or simply as a refreshing daily drink, kombucha represents a compelling intersection of ancient wisdom and modern food science.

Reference:

Massoud, R., Jafari, R., & Khosravi-Darani, K. (2024). Kombucha as a health-beneficial drink for human health. Plant Foods for Human Nutrition, 79(2), 251-259.

Date of Input: 21/05/2026 | Updated: 21/05/2026 | nurulizzah