Experts Weigh Health Benefits of Kombucha Amid Limited Evidence

Interest in kombucha, a fermented tea drink, has surged as many consumers tout its potential health benefits. While some anecdotal evidence suggests improvements in gut health and overall wellness, experts caution that scientific backing is still limited.

Gabriela Fraiz, a doctoral student at the Federal University of Vicosa in Brazil, claims to have experienced positive changes in her gut health since incorporating kombucha into her lunch routine. After drinking the fermented tea, she reports feeling less bloated and gassy. Additionally, she enjoys the fizzy, slightly citrusy, and sweet flavor that comes from brewing it herself. However, experts like Fraiz emphasize that while social media is filled with claims about kombucha’s ability to aid in weight loss, manage Type 2 diabetes, and reduce the risk of heart disease and cancer, many of these assertions lack substantial human research.

What is Kombucha?

Kombucha is created through a fermentation process involving tea, sugar, and a symbiotic culture of bacteria and yeast, commonly known as a SCOBY. During fermentation, yeasts convert sugar into alcohol and carbon dioxide, which gives kombucha its effervescence. Bacteria further process the alcohol into various acids, imparting a distinctive vinegary taste. Commercial kombucha must contain less than 0.5 percent alcohol to avoid being categorized as an alcoholic beverage. While typically low in sugar, some brands enhance their products with additional sugars or fruit juices, according to Heather Hallen-Adams, an associate professor at the University of Nebraska-Lincoln. The drink can also be flavored with fruits, herbs, or spices.

Potential Health Benefits of Kombucha

Research into the health benefits of kombucha has primarily relied on animal studies, which have suggested links to reduced inflammation and improved blood sugar control. However, there are only a few human clinical trials, often small and yielding inconclusive results. A recent randomized controlled trial conducted in 2024 involved approximately 60 participants with excess body weight. Those who consumed about seven ounces of kombucha daily for ten weeks did not experience significant weight loss compared to those who did not drink it. Although some participants reported less acid reflux and bloating, their gut microbiome showed little change.

Another small trial in 2024 examined 16 participants who drank two cups of kombucha daily for four weeks. The results indicated no measurable improvements in blood pressure, cholesterol, or inflammation levels compared to those who abstained from the drink. Yet, some studies hint at kombucha’s potential in regulating blood sugar levels. In one study involving 11 healthy adults in 2023, participants showed approximately 20 percent lower blood sugar responses after meals when consuming kombucha compared to other beverages. Additionally, another trial indicated that a daily cup of kombucha for four weeks significantly lowered fasting blood sugar levels in individuals with Type 2 diabetes, though this study involved only 12 participants.

Dr. Dan Merenstein from Georgetown University notes that while preliminary findings are encouraging, the small scale of these studies makes it difficult to draw definitive conclusions. He, along with other experts like Justin Sonnenburg, a microbiology professor at Stanford University, stresses the need for higher quality research to better understand kombucha’s health impact.

Although robust evidence is lacking, some research indicates that a diet rich in various fermented foods, including kombucha, yogurt, and kimchi, may promote a healthier microbiome and lower inflammation throughout the body.

Experts recommend a cautious approach to incorporating kombucha into diets. Dr. Sonnenburg advises that while low-sugar kombucha is unlikely to pose health risks, it remains a healthier alternative to sugary sodas or cocktails. When purchasing store-bought kombucha, consumers should opt for products with simple ingredient lists consisting of tea, sugar, and potentially fruit juice or spices, avoiding those with excessive added sugars.

For those interested in brewing their own kombucha, Dr. Hallen-Adams suggests obtaining a SCOBY from a reputable retailer. Homemade batches require careful attention to cleanliness to avoid harmful bacteria or mold. If signs of mold appear, it is essential to discard both the batch and the SCOBY. Dr. Merenstein further advises that individuals with compromised immune systems should stick to commercially prepared varieties, as there have been rare instances of severe illness linked to homemade kombucha, including liver injury and acidosis.

As kombucha continues to gain popularity, the conversation around its health benefits remains vibrant, underscored by the need for more rigorous scientific exploration.