Kombucha, a fermented tea-based beverage, has surged in popularity, touted as a health elixir with benefits ranging from weight loss to cancer prevention. But what does the science say? This article explores the purported weight loss benefits of kombucha, examining the evidence and offering a balanced perspective.
What is Kombucha?
Kombucha is a fermented drink made from tea (typically black or green), sugar, bacteria, and yeast. The bacteria and yeast form a symbiotic culture (SCOBY) that consumes the sugar during fermentation, resulting in a slightly fizzy, vinegary beverage. The fermentation process adds a bit of alcohol to kombucha, but alcohol levels are typically below 0.5%, allowing traditional kombucha to be sold as a nonalcoholic beverage. Kombucha dates back more than 2,000 years.
Potential Benefits of Kombucha
Kombucha contains probiotics, B vitamins, enzymes, antioxidants, glucosamine, and certain acids, which proponents claim offer various health benefits. Many of kombucha’s touted benefits are similar to those of other fermented foods, like sauerkraut, pickles, kimchi, kefir and yogurt.
Gut Health: Kombucha introduces "good" bacteria into the gut, potentially improving digestion, nutrient absorption, and overall metabolism. A healthy gut flora and properly functioning digestive tract can both positively impact your overall health, but also your weight-loss efforts. Nearly every single cell in our body relies on bacteria. And when the balance of good and bad bacteria in our gut is unbalanced (this is called dysbiosis), our health can become compromised.
Inflammation: Kombucha is rich in antioxidants and polyphenols, which may help protect the body from damage and limit chronic inflammation. Polyphenols are known to act as strong antioxidants in the body and decrease inflammation, which is the root cause of many diseases and conditions. And the fermentation process actually increases the amount of polyphenols.
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Immune System: The B vitamins and organic acids in kombucha may contribute to a stronger immune system. The fermented tea also is high in acetic, glucuronic and D-Saccharic acids. These organic acids can be antimicrobial, making them something of a superhero in the fight against bad bacterial growth, says Smith.
Heart Health: Some studies suggest that kombucha may improve cholesterol levels and limit plaque buildup in arteries. Studies show that kombucha can increase your “good” HDL cholesterol and decrease your “bad” LDL cholesterol, notes Zumpano.
Detoxification: Enzymes and acids in kombucha can assist your liver as it gets rid of undesired compounds in your body, says Smith. Some research even suggests kombucha may have potential as a therapeutic dietary supplement to combat fatty liver disease.
Kombucha and Weight Loss: What the Research Says
While kombucha is often promoted as a weight loss aid, scientific evidence supporting this claim is limited.
Animal Studies: A study published in PLOS Genetics used a worm model to investigate kombucha's effects on fat accumulation and triglyceride levels. Researchers from The University of North Carolina at Chapel Hill found that microbes from kombucha colonized the worms' intestines, creating metabolic changes similar to those that occur during fasting. Animals ingesting a diet including probiotic microbes found in kombucha tea experienced a reduction in fat accumulation and a lowering of triglyceride levels.
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Human Studies: There is a lack of sufficient evidence for significant clinical benefits of kombucha in humans.
It is important to note that much of the evidence supporting kombucha's health benefits is anecdotal or based on animal studies. Further research is needed to confirm these effects in humans.
How Kombucha Might Support Weight Loss
Despite the lack of direct evidence, kombucha may indirectly support weight loss efforts through several mechanisms:
Probiotics and Gut Health: The probiotics in kombucha can promote a healthy gut microbiome, which is linked to improved digestion, nutrient absorption, and metabolism. A balance of proper gut bacteria aids in digestion, nutrient absorption, and overall metabolism.
Metabolism Boost: The caffeine in kombucha may provide a slight metabolic boost, helping to burn more calories. Research has shown that caffeine can promote weight and body fat reduction. Some people also feel a slight increase in energy after consuming kombucha, which may be attributed to the caffeine content, and find it helpful to drink prior to exercise to provide a little boost.
Reduced Fat Accumulation: Researchers from The University of North Carolina at Chapel Hill say that drinking kombucha tea may also help reduce fat accumulation and lower triglyceride levels via a worm model.
Lower Triglyceride Levels: High triglyceride levels in the body are associated with an increased risk for cardiovascular disease. Researchers from The University of North Carolina at Chapel Hill say that drinking kombucha tea may also help reduce fat accumulation and lower triglyceride levels via a worm model.
Sugar Substitute: Kombucha can be a healthier alternative to sugary drinks like soda, helping to reduce overall calorie intake. Just be cautious about what kombucha you buy if you’re counting calories. Some types of kombucha are more sweetened than others, so try to choose one with lower amounts of sugar.
Potential Risks and Considerations
Sugar Content: Some kombucha varieties are high in sugar, which can negate any potential weight loss benefits. It is important to choose kombucha with minimal added sugar. Some manufacturers will add sugar and juice once the fermentation process is complete, which drives up the final sugar content. Look for varieties that are organic and contain minimal sugar (usually around 4 to 6 grams or less), and that don’t contain any added artificial ingredients, such as sweeteners or colors.
Caffeine: Kombucha contains caffeine, which may cause side effects in some individuals, such as quickened heartbeat or heartburn.
Interactions with Medications: Kombucha can interact with diabetes medication and antabuse medication. It is important to note kombucha can interact with diabetes medication, although worth noting, from studies on animal models, and can have hypo (low) glycemic, or low blood glucose effects, depending on the ingredients, person, and medication interaction. It can also interact with antabuse medication.
Homemade Kombucha: Homemade kombucha may pose risks due to potential contamination and lead poisoning if brewed in ceramic pots with lead. Sanitation also can be an issue when brewing a homemade batch of kombucha. The drink can become tainted if it’s contaminated with undesirable fungi and overproduction of yeast, she adds. (Watch for odd coloring or a smell that resembles nail polish.) People who have compromised immune systems should be careful with homemade kombucha consumption as contamination is possible, and there is also the potential for the yeast to grow bacteria that may be harmful for those individuals.
Digestive Issues: Some people may experience gastric distress from drinking kombucha. Have tried kombucha and found that it causes gastric distress.
How Much Kombucha Should You Drink?
The Centers for Disease Control and Prevention advises that drinking approximately 4 ounces (oz) of kombucha per day “may not cause adverse effects in healthy persons.” Note that most kombucha bottles sold at the store are more than 4 oz. Check recommended serving sizes before chugging down a whole container. If you’re new to kombucha, it’s best to start slow.
Who Should Avoid Kombucha?
People who are pregnant or breastfeeding or who have weakened immune systems should avoid kombucha tea. Kombucha is generally not recommended for young children, either.