Do you Drink Kombucha? A trip on Chicago’s Green Line made me immediately rethink all of kombucha’s health benefits

Have you ever heard of kombucha? It’s a fermented tea that’s increasing in popularity due to its health benefits. It’s like tea mixed with vinegar with a loose piece of tissue floating in it—sounds appealing right? If Gatorade is the drink of athletes, kombucha is the unofficial drink of hipsters. If there were a hipster Olympics, with games like mustache twisting, latte art, and inexplicable scarf wearing—kombucha brands would surely line up to sponsor it. For the record, I can appreciate the beauty of a good latte leaf, but I’m NO hipster.

Although I don’t claim hipster-dom, I am a kombucha drinker. I started drinking kombucha before I even knew what a hipster was. Then again, I was drinking kombucha before I truly understood what kombucha was. An incident on Chicago’s Green line (a public train) forced me to rethink what I was drinking. Let me share my story and break down some facts about kombucha’s health benefits.

Is he a hipster or a Civil War soldier? Hard to say?

My kombucha story—the event that made me look up kombucha’s health benefits.

A few years ago when I was training gastroenterology, my geriatric Jeep Cherokee would routinely break down. Not having a functional car frequently forced me to use public transportation to get to and from the hospital in the middle of the night. At that time, I was living in Chicago’s Woodlawn neighborhood on the Southside and working at Rush University Medical Center on the near Westside. When I would get called into the hospital at 2 am, I would put on some street clothes (typically a hoodie and boots), jog eight blocks to 63^rd and Cottage Grove, and hop on the green line.

One night, after treating someone with cirrhosis for gastrointestinal bleeding, I jumped on the train at 3 am to come home. I threw on my headphones, started playing “Mass Appeal” by Gangstarr, and I cracked open a bottle of kombucha. Everything was cool. At least it was until I heard someone say,“Yo, fam.” I looked up and saw a group of guys trying to ask me a question. I’m social a dude, but talking to random people on the green line at 3 am isn’t exactly a ‘happy hour.’

I slowly took off my headphones and gave them a nod. One guy asked me “why does my drink have a whole bunch of ‘boogers’ in it [referring to the probiotic bacterial culture that floats around in kombucha]?” Ahh…I paused and tried to think of a witty, educational, and non-threatening response. I had nothing. All I could muster was, “It’s kombucha bruh—it has health benefits.”

Now as a gastroenterologist, I should have provided a thought-provoking, educational response; but at 3 in the morning, I wasn’t exactly in the mood to act like Lavar Burton on Reading Rainbow. However, I thought about their question further as I got off the train, “Why am I drinking a drink with ‘boogers’ in it and is it really healthy for you?”

What is kombucha?

black tea leaves

Kombucha is a fermented tea. Its origins are slightly murky, but it likely originated in China during the Tsin Dynasty (220 B.C.). About 200 years later, a Dr. Kombu brought the drink to Japan to heal the emperor’s gastrointestinal problems —hence the name kombucha (1).

Making kombucha entails cultivating tea (usually green or black) with a symbiotic culture of bacteria and yeast, affectionately called SCOBY. The SCOBY produces various acids, carbon dioxide, and alcohol through the process of fermentation (2).

Symbiotic Culture of Bacteria and Yeast (SCOBY)

What are the presumed health benefits of kombucha?

If you google ‘kombucha,’ you’ll find a wide variety of health claims associated with it including improving mental clarity, anti-cancer properties, improved gut health, a decreased risk of inflammatory disease, curing AIDS, treating gout, etc. Just looking at kombucha’s magical properties on the Internet made me feel like a genie would pop out if I rubbed the bottle hard enough. I tried—there were no genies, just a bunch of effervescent bubbles. After being disappointed by the lack of genies, I wondered if any of these health claims had evidence supporting them.

via GIPHY

What does actual published research say about kombucha? The Good, The Bad, and the FUGLY.

The GOOD

• Kombucha is usually low in calories and sugar, making it better than pop.
• It contains a variety of bacteria that may contribute to the microbial ecosystem of the gut. These bacteria and yeast may modulate the immune system and the function of the gastrointestinal tract (3).
• There are a variety of vitamins and minerals in kombucha. Studies have shown that these vitamins include B1, B2, B6, B12, and C (2).
• Kombucha also contains tea polyphenols that may have antioxidant properties along with bioactive amino acids (2).
• The acetic acid and lactic acid produced during the fermentation process likely give kombucha anti-microbial properties (4)
• Studies done in mice and rats indicate that Kombucha may improve blood sugar levels, heal stomach ulcers, and decrease cholesterol (2).
• The USDA did studies in the mid-90s that showed kombucha was safe for human consumption (5).

The Bad

Research Photo by Lucas Vasques on Unsplash

• No clinical trials using kombucha have been done in humans (6). This doesn’t mean that kombucha doesn’t have any health benefits—it just means that no one has adequately studied or proven its benefits.
• In 2010, kombucha was briefly taken off the shelves of Whole Foods stores due to inspections that found that the alcohol content in Kombucha was frequently higher than 0.5% alcohol by volume, the legal limit for non-alcoholic beverages (1).
• Due to the alcohol content, drinking kombucha isn’t safe during pregnancy or breastfeeding.
• There are reports of mild side effects from drinking kombucha. These side effects include allergic reactions, jaundice, nausea, vomiting, and head and neck pain (7)

The FUGLY

• In rare cases, kombucha may cause severe health issues. These cases typically involve home-brewed kombucha, not the popular brands sold in many stores.
• According to the Center for Disease Control, one person may have died in 1995 from drinking too much homemade kombucha. In this case, the kombucha was likely too acidic (8).
• One person drinking kombucha developed kidney failure and lactic acidosis, a life-threatening condition characterized by too much acid in the bloodstream (9).

What’s the bottom line?

• Kombucha may have health benefits, but these benefits have not been adequately proven in humans. All of the studies showing kombucha’s health benefits have been done in mice or rats.
• Most commercial brands of kombucha are likely safe. The safety of home-brewed kombucha varies due to the risk of contamination and excessive acid production.
• Pasteurized kombucha is the safest, but it’s also the least likely to have significant health benefits since pasteurization likely kills any possible probiotics in the tea.
• People with chronic kidney disease and people who take metformin (a medication for diabetes) possibly have an increased risk for lactic acidosis when drinking too much kombucha.
• Individuals who take medications that weaken the immune system (people with inflammatory bowel disease, lupus, undergoing chemotherapy, etc.), should consider avoiding kombucha due to the potential risk of bacterial/candida infections.
• I’m still going to drink commercial brands of kombucha because they’re low in calories. Outside of that, no one knows what kombucha is actually doing for you.

References:

1. https://www.forbes.com/sites/christinatroitino/2017/02/01/kombucha-101-demystifying-the-past-present-and-future-of-the-fermented-tea-drink/2/ – 53a31fb97099
2. Jayabalan, R., Malbaša, R. V., Lončar, E. S., Vitas, J. S. and 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, 13: 538–550. doi:10.1111/1541-4337.12073
3. Chakravorty, S., Bhattacharya, S., Chatzinotas, A., Chakraborty, W., Bhattacharya, D., & Gachhui, R. (2016). Kombucha tea fermentation: Microbial and biochemical dynamics. International Journal of Food Microbiology, 220, 63–72.
4. Sreeramulu G, Zhu Y, Knol W. Kombucha fermentation and its antimicrobial activity. J Agric.Food Chem. 2000;48:2589-94.
5. Food and Drug Administration. 1995. FDA cautions consumers on “Kombucha Mushroom Tea” (News release). Washington, DC: US Department of Health and Human Services, Public Health Service, Food and Drug Administration.
6. Ernst E. Kombucha: a systematic review of the clinical evidence. Komplementarmed.Klass.Naturheilkd. 2003;10:85-7.
7. Srinivasan R, Smolinske S, Greenbaum, D. 1997. Probable gastrointestinal toxicity of kombucha tea: is this beverage healthy or harmful?. J Gen Intern Med 12:643–4.
8. Centers for Disease Control and Prevention. Unexplained severe illness possibly associated with consumption of Kombucha tea—Iowa, 1995. JAMA 1996;275:96-8.
9. Kole AS, Jones HD, Christensen R, Gladstein J. 2009. A case of kombucha tea toxicity. J Intensive Care Med 24:205–7.

Dr. Ed McDonald

I am a physician and trained chef. I specialize in gastroenterology and nutrition. Currently I work as the Associate Director of Adult Nutrition at the University of Chicago.