The only reason to drink kombucha is because it makes you feel healthier. After all, no diet or study contains more wisdom than your body. At Body Ecology, we know that kombucha is popular. But this information is for people who don’t feel good when they drink kombucha — and they don’t know why.
Kombucha is a sweet fermented tea that is made with “tea fungus,” or a floating network of bacteria and yeast.
Kombucha tea fungus is also called a SCOBY, an acronym for “symbiotic community of bacteria and yeast.”
Kombucha first showed up in northeast China. Around 1,600 years ago, it then traveled to Japan where it was used to cure the digestive problems of the Emperor Inkyo. As trade routes expanded, the tea made its way into Russia and eventually Germany, France, North Africa, and Italy.
As popular as it is, kombucha is a wild and unpredictable ferment. You can safely ferment your own cultured vegetables at home, teeming with friendly bacteria, by using the Veggie Culture Starter.
These days, kombucha is available worldwide. You can buy it at most grocery stores, or you can make it at home with tea fungus, black tea, and sugar. Kombucha wouldn’t have survived for thousands of years if it didn’t have something to offer. But kombucha isn’t without risk.
In a recent review, researchers warned against pregnant women, lactating mothers, and those with compromised immune systems drinking kombucha.1
Are there health benefits to kombucha? Yes. Both folk medicine and animal studies tell us that kombucha has a lot to offer.
Is kombucha on The Body Ecology Diet? No. Read on to find out why.
4 Reasons to Reconsider Kombucha Tea
- Kombucha may contain Candida yeast.
In a study from 1995, investigators found that two samples of homebrewed kombucha (from a pool of 32) were contaminated with Candida albicans — the same opportunistic yeast that can take over your gut and invade your body.2
While this is one small study concerning two samples (that came from the same home), it drives home the fact that kombucha is a wild ferment.
You never really know what’s in your tea fungus or SCOBY. And microbes work together — the presence of one can easily trigger the growth of another.
Scientists can tell us about general trends. For example, there are specific strains of yeast and bacteria that show up in tea fungus again and again. That said, the SCOBY in your homebrewed kombucha changes according to its environment. It can become contaminated, housing molds and fungi that cause illness.
- Kombucha contains alcohol.
One of the trends that researchers have noticed is that tea fungus contains yeast. And many of the strains in kombucha are the same yeast strains that are used in beer and wine production.3
Indeed, kombucha contains far more yeast than bacteria. One yeast — known as Zygosaccharomyces bailii or Z. bailii — is common in both kombucha and the food industry.
Z. bailii is extremely robust.4 It can live off of food preservatives and spoil “shelf-stable” foods such as:
- Fruit concentrates
- Soft drinks
- Salad dressing
When the yeasts in kombucha feed on sugar, they produce alcohol and gas. Like Candida, Z. bailii also produces acetaldehyde as it feeds on sugar.5 Acetaldehyde is an irritant, carcinogen, and air pollutant that is found in cigarette smoke and car exhaust. At high enough levels in the body, it can lead to a rapid pulse, sweating, skin flushing, nausea, and vomiting.6
If you’ve ever had a hangover, you have felt the effects of too much acetaldehyde.
When brewing kombucha, the alcohol content increases with time (around the sixth day) and then slowly decreases.7 One study found that kombucha contains as much as 5.5 g/L of alcohol — or 2.8% alcohol.8 Kombucha that is allowed to brew for a longer period of time contains less alcohol (but possibly more acetaldehyde).
- Kombucha may contain heavy metals and fluoride.
The tea fungus (or SCOBY) floating around in your kombucha is biosorbent. Like a magnet to iron, it binds to contaminants and heavy metals.
Biosorbents are used to clean up the environment and wastewater.
Indeed, several studies have found that a kombucha tea fungus effectively removes heavy metals like copper, chromium, and arsenic from wastewater.9,10
Other research shows that kombucha itself contains small amounts of lead and chromium. There have even been a few documented cases of lead poisoning from kombucha.11,12
If you’re concerned about fluoride, a 2008 study published in Food Chemistry found kombucha to contain as much as 3.2 mg/g of fluoride.13 This is significantly more than what’s found in unfermented black tea.
Kombucha tea fungus will absorb and sometimes even magnify pollutants.
When making kombucha at home or buying from a manufacturer, both air quality and water quality matter. So does your storage vessel — pass on stoneware that may be coated with a lead or cadmium glaze.
- Kombucha contains sugar.
Common table sugar — which also goes by the name of cane sugar, beet sugar, or sucrose — powers the fermentation of kombucha.
Yet a considerable amount of sugar is left unfermented in kombucha. (14)
In 2001, researchers at Bucharest University found that a little over 34% of sugar remains after seven days of fermentation. After 21 days, this percentage drops to 19%. This is why kombucha still tastes sweet — even though it’s fermented. If you're looking to end your sugar cravings, here are some secrets to help you out.
The Only Reason to Drink Kombucha: A Reminder
For the reasons listed above, kombucha isn’t on The Body Ecology Diet. It falls into the category of a wild ferment and is too much of a threat to a recovering immune system. The sugar in kombucha also feeds Candida yeast.
But many people report feeling better when they drink kombucha.
This all comes back to the Principle of Uniqueness. It's all about what works best for you. But for some, the sugar, the small amount of alcohol, and wild strains of yeast in kombucha are enough to keep you from reaching your health goals.
What To Remember Most About This Article:
Kombucha is a celebrity favorite, but how does it fit into a healthy diet? Researchers have warned that pregnant and nursing women and those with compromised immune systems should avoid kombucha. Kombucha has some health benefits, but it is not on The Body Ecology Diet.
Here are four things you may not expect to find in your fermented tea:
- Candida yeast. Researchers have found kombucha contaminated with opportunistic Candida. Since kombucha is a wild ferment, you never know what you're going to get.
- Alcohol. Yeast in kombucha that feed on sugar produce alcohol and gas. Kombucha yeast also produce the irritant, carcinogen, and pollutant acetaldehyde that can cause rapid pulse, sweating, flushing, nausea, and vomiting when consumed in excess.
- Heavy metals and fluoride. Research confirms that kombucha may contain small amounts of lead and chromium; there have been documented cases of lead poisoning from kombucha.
- Sugar. Despite the fermentation process, a large amount of sugar is left unfermented in kombucha. 19% of sugar may remain in the tea after 21 days of fermentation.
- Jayabalan, R., Malbaša, R. V., Lončar, E. S., Vitas, J. S., & 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(4), 538-550.
- Mayser, P., Fromme, S., Leitzmann, G., & Gründer, K. (1995). The yeast spectrum of the ‘tea fungus Kombucha’. Mycoses, 38(7‐8), 289-295.
- Teoh, A. L., Heard, G., & Cox, J. (2004). Yeast ecology of Kombucha fermentation. International journal of food microbiology, 95(2), 119-126.
- Martorell, P., Stratford, M., Steels, H., Fernández-Espinar, M. T., & Querol, A. (2007). Physiological characterization of spoilage strains of Zygosaccharomyces bailii and Zygosaccharomyces rouxii isolated from high sugar environments. International journal of food microbiology, 114(2), 234-242.
- Marsh, A. J., O'Sullivan, O., Hill, C., Ross, R. P., & Cotter, P. D. (2014). Sequence-based analysis of the bacterial and fungal compositions of multiple kombucha (tea fungus) samples. Food microbiology, 38, 171-178.
- Swift, R., & Davidson, D. (1998). Alcohol hangover. Alcohol Health Res World, 22, 54-60.
- Reiss, J. (1994). Influence of different sugars on the metabolism of the tea fungus. Zeitschrift fuer Lebensmittel-Untersuchung und Forschung, 198(3), 258-261.
- Chen, C., & Liu, B. Y. (2000). Changes in major components of tea fungus metabolites during prolonged fermentation. Journal of Applied Microbiology, 89(5), 834-839.
- Razmovski, R., & Šćiban, M. (2008). Biosorption of Cr (VI) and Cu (II) by waste tea fungal biomass. Ecological Engineering, 34(2), 179-186.
- Mamisahebei, S., Khaniki, G. R. J., Torabian, A., Nasseri, S., & Naddafi, K. (2007). Removal of arsenic from an aqueous solution by pretreated waste tea fungal biomass. Iranian Journal of Environmental Health Science & Engineering, 4(2), 85-92.
- Phan, T. G., Estell, J., Duggin, G., Beer, I., Smith, D., & Ferson, M. J. (1997). Lead poisoning from drinking Kombucha tea brewed in a ceramic pot. The Medical journal of Australia, 169(11-12), 644-646.
- Sabouraud, S., Coppere, B., Rousseau, C., Testud, F., Pulce, C., Tholly, F., ... & Descotes, J. (2009). [Environmental lead poisoning from lead-glazed earthenware used for storing drinks]. La Revue de medecine interne/fondee... par la Societe nationale francaise de medecine interne, 30(12), 1038-1043.
- Kumar, S. D., Narayan, G., & Hassarajani, S. (2008). Determination of anionic minerals in black and kombucha tea using ion chromatography. Food chemistry, 111(3), 784-788.
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