Probiotics in kombucha could mimic effects of fasting

According to Rob Dowen, PhD, professor of cell biology and physiology in the School of Medicine at The University of North Carolina at Chapel Hill and lead author of this study, it is important to discover new ways for people to reduce fat accumulation and lower triglyceride levels in the body because modern diseases including diabetes, hypertension, and cardiovascular disease are among the leading contributors to early death.

“These diseases fall into the category of metabolic syndromes, which are often associated with dysregulation of lipid homeostasis, resulting in high plasma triglycerides, elevated blood pressure, and obesity,” Dowen explained to Medical News Today.

“Investigation of functional foods that may directly improve lipid homeostasis during metabolic disease, or that could serve as a supplement to traditional therapeutic approaches, is paramount to identifying new strategies to support long-term health in the modern age,” he added.

For this study, Dowen and his team focused on kombucha tea as a potential way of lowering triglyceride levels.

“This ancient beverage, which has roots in Eastern traditional medicine, has seen a steady resurgence in popularity since the turn of the century and is prevalent in the beverage retail space despite a striking lack of mechanistic information about how its consumption impacts the consumer,” Dowen explained.

Kombucha tea is a fermented drink made from black tea and a symbiotic culture of bacteria and yeast (SCOBY). The addition of bacteria and yeast also makes it a probiotic beverage.

Previous animal and small-scale human studies suggest kombucha may be helpful in the treatment of several diseases, including diabetes, liver disease, and gut health.

Other animal and pre-clinical research has found that kombucha may assist with different aspects of cardiovascular health, such as lowering cholesterol levels and high blood pressure.

It is important to note that past research does show that some people may experience side effects when drinking kombucha including a quickened heartbeat or heartburn due to additional caffeine from the drink.

A case study published in June 2022 suggests kombucha consumption may sometimes have cardiotoxic effects.

Researchers based their study on a worm model.

“Our favorite animal model system to use in the lab is the nematode Caenorhabditis elegans, which consumes bacteria as (its) primary food source,” Dowen said. “This allows us to directly study the relationship between the host and the probiotic microbes found in kombucha tea in a genetically tractable model system.”

Through the worm model, scientists found that after ingesting kombucha tea, microbes from the tea colonized the worms’ intestines, creating metabolic changes similar to those that occur during fasting.

“We were very surprised to find that the probiotic microbes in kombucha tea could colonize the worm gut and stimulate a fasting-like metabolic response in the host, which occurred despite the fact that these animals showed no defects in intestinal nutrient absorption,” Dowen explained.

“Incredibly, this response was only seen in animals consuming microbes isolated from a long-term, fully fermented kombucha tea culture and not a simple mix of non-fermenting kombucha-associated microbes. This observation suggested that microbial metabolites produced during the fermentation process could be shaping host metabolic pathways,” he added.

Dowen and his team also discovered via the worm model that animals ingesting a diet including probiotic microbes found in kombucha tea experienced a reduction in fat accumulation and a lowering of triglyceride levels.

“These findings are significant as they are consistent with purported human health benefits of kombucha tea, which include protection against metabolic diseases, improved liver function, and reduced fat accumulation.”
— Rob Dowen, PhD

“Much of this evidence is anecdotal or is not supported by detailed mechanistic studies. Thus, our findings are very exciting as they corroborate the human health benefits of kombucha tea and provide mechanistic insight into how host metabolism may be altered by kombucha-associated probiotic microbes,” Dowen continued.

“It is important to point out that our study was performed in a model organism in the lab, and thus, our results will need to be substantiated and expanded upon in mammalian model systems to further inform how kombucha consumption impacts human physiology,” he noted.

After reviewing this study, Cheng-Han Chen, MD, a board certified interventional cardiologist and medical director of the Structural Heart Program at MemorialCare Saddleback Medical Center in Laguna Hills, CA, told MNT this study is interesting and hypothesis-generating and definitely can be a stepping stone for future research.

“We know that saturated fat intake is a big risk factor for cardiovascular disease. Obesity, saturated fat intake (and) cholesterol levels — they’re all risk factors for heart disease. If there was a way to adapt your gut so that it won’t absorb as much of the saturated fats and won’t metabolize as much of them, then it could have health benefits (for) the cardiovascular system,” Chen explained.

“It would be great to study these types of effects in more complex organisms, maybe even in mammals, and eventually this should help guide the direction of research for the benefits of kombucha in humans,” he added.

MNT also spoke with Monique Richard, a registered dietitian nutritionist and owner of Nutrition-In-Sight, about this study.

Richard said that currently there is a lack of sufficient evidence for significant clinical benefits of kombucha.

“(This) is not to say there are no health benefits from consuming kombucha such as from the tea — black or green — itself which provides polyphenols and additional ingredients such as B vitamins, but I would also urge consumers to take into consideration one, the amount of sugar that is in the kombucha (and) two, the amount of caffeine,” she explained.

“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,” Richard added.

Before downing bottles of kombucha or practicing harnessing SCOBY in your own kitchen, Richard advised to meet with a registered dietitian nutritionist (RDN) to figure out the root cause of what may be contributing to elevated fat accumulation or high triglycerides.

“Hint — it likely could be a combination of diet, lifestyle, and genetics, in addition to other factors that should be addressed,” she added.