Kombucha is a sweet fermented tea that is made with “tea fungus,” or a floating network 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.
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.
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.
1. 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.
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.
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.
2. 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
Wine
Soft drinks
Syrups
Ketchup
Pickles
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.
THE ONLY REASON TO DRINK KOMBUCHA
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.
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.
The sugar, the small amount of alcohol, and wild strains of yeast in kombucha are enough to keep you from reaching your health goals.