The name alone sounds exotic, like an elixir of health from a faraway land. Indeed, it’s believed that kombucha—which is defined as a beverage produced by fermenting sweet tea with a culture of yeast and bacteria—originated in northeast China some 2,000 years ago. It can now be found in supermarkets across America. Kombucha is believed to confer some incredible health benefits, but it’s far from the first product to get swept up in the superfood craze. So is kombucha just another product of the hype, or is there real research to back up its potential as a health and wellness panacea? We cut through the noise to bring you the facts about this trendy beverage.
The key component of kombucha is an active starter culture of bacteria and yeast. This is often referred to as a SCOBY, short for Symbiotic Culture of Bacteria and Yeast. It typically looks like a circular, semi-translucent disc:
The SCOBY is added to a sweet tea (either black or green). There, it feeds on the existing sugars, acids and caffeine inside the tea. After an extended period (typically 7 to 30 days), you’re left with a fizzy, vinegary fermented beverage that’s swimming with live microorganisms. The fermentation process does give kombucha a slight alcoholic quality, but most formulations are 0.5% ABV or less (therefore making them legal for those under 21 years of age to purchase in the U.S.).
GT’s Kombucha is one of the—if not the—best-selling kombucha brands in America. A 16-ounce bottle of GT’s Original Enlightened Raw Kombucha contains 60 calories, 0 grams of fat, 0mg cholesterol, 20mg sodium, 14 grams of carbohydrate, 4 grams of sugar, 0 grams fiber and 0 grams of protein. It also includes 50% of the recommended daily value (RDV) of folate, 40% RDV vitamin B2, 40% RDV vitamin B6, 40% RDV vitamin B1, 40% RDV vitamin B3 and 40% RDV vitamin B12.
Those basic nutrition facts are pretty strong. The drink contains a fraction of the sugar that you’d find in most sodas or fruit juices, and it also contains plenty of useful B vitamins. Folate—also referred to as folic acid or vitamin B9—is crucial for proper brain function and plays a big role in mental and emotional health. B1, also known as thiamine, breaks down carbohydrates for energy and assists in proper nerve function. B2, also known as riboflavin, and B3, also known as niacin, assist with carbohydrate, amino acid (protein) and fat metabolism. B6 aids in red blood cell production and amino acid and carbohydrate metabolism. B12 regulates the functions of cells in the G.I. tract, bone marrow and nerve tissue. These are all good things.
However, kombucha’s supposed health and wellness superpowers have little to do with its vitamin or mineral content. Instead, it’s the probiotics found in kombucha that are largely believed to be so valuable. Large amounts of probiotics are created during the fermentation process. Probiotics are a proven way to increase the healthiness of our gut microbiome, which can in turn have wide-ranging health benefits. “Probiotics are live microorganisms that beneficially affect your gut by selectively stimulating the growth or activity of a limited number of healthy bacteria in the colon,” says Kristin Kirkpatrick, lead dietician at the Cleveland Clinic Wellness Institute. “Getting more good bugs in there via probiotics can help benefit overall health.”
To understand why probiotics may have such a major effect on health, you must understand the gut microbiome. Humans are covered inside and out with trillions of bacteria. Most of it lies within our gut in what is known as the “gut microbiome,” which consists of yeasts, fungi and roughly 3 to 4 pounds of bacteria. More than 5,000 species of bacteria live in the gut. The exact actions and purpose of many bacteria are still a mystery, but projects like the National Institute of Health’s Human Microbiome Project are spending massive amounts of time and money to better understand bacteria within the body and to “look for correlations between changes in the microbiome and human health.”
Thus far, studies have connected the condition of the gut microbiome to autism, diabetes, obesity, cancer, IBS, arthritis, Parkinson’s disease, allergies, inflammation, acne and more. Generally speaking, the more diverse a person’s microbiome, the better. Lean, healthy people have more diverse bacteria in their gut than obese, unhealthy people, and the average American gut is less diverse than that of people in other countries with healthier populations. In most cases, a diverse gut equals a healthy gut, one that’s adept at keeping the body running optimally. If you believe the probiotics in kombucha are important, it’s key to buy raw/unpasteurized kombucha. The temperatures that occur during pasteurization would likely kill the probiotics.
The fact kombucha is made with tea is another plus for its potential status as a health-boosting beverage. Catechins, a powerful antioxidant abundant in many teas (especially green tea), has been shown to aid in the prevention of cancer, osteoporosis and cardiovascular diseases. Tea consumption has also been linked to increased dental health, lower cholesterol and enhanced immune system function.
While the combination of probiotics and tea certainly sounds like the making of a healthy beverage, the research regarding kombucha’s effect on human health is lacking. Most of the existing research has utilized animal subjects, not human. However, the results of those studies have been largely encouraging.
For example, multiple animal studies have found kombucha can help prevent liver disease brought about by oxidative stress. Kombucha was also found to have “attractive curative effects” on the liver and kidney functions of diabetic rats, so much so that the study’s authors concluded kombucha can “be considered a potential strong candidate for future application as a functional supplement for the treatment and prevention of diabetes.” Test-tube studies have even found kombucha can help battle cancer, as one such study found kombucha “significantly decreases the survival of prostate cancer cells by downregulating the expression of angiogenesis stimulators.”
So there’s certainly merit to the idea that kombucha can be a powerful, health-enhancing tonic. However, some proponents of the beverage take these potential benefits way too far. “There are people out there telling you—it’ll cure cancer, it’ll cure diabetes, it’ll cure cardiac illness, it’ll build your immune system, it’ll prevent herpes, it’ll reverse AIDS,” microbiologist Heather Hallen-Adams recently told VICE. These are wildly irresponsible claims, as we still have little idea of how exactly kombucha impacts human health. “There isn’t enough evidence that kombucha tea delivers on its health claims,” the Mayo Clinic states on that matter. “At present…valid medical studies of kombucha tea’s role in human health are very limited.”
If you’re interested in trying kombucha, there’s no reason you shouldn’t give it a shot. However, you need to be aware that it’s no replacement for a healthy, balanced diet high in plant-based foods. You also need to be weary of products like “kombucha sodas” that can contain significant amounts of added sugar. When in doubt, check the ingredients. You can brew your own kombucha, but it does come with some serious risks. Negligent brewing practices can lead to unwanted harmful bacteria inside the drink, which brings about obvious concerns. I’d recommend either sticking with store-bought versions or seeking out an accomplished home brewer who has a track record of making clean, pure kombucha.