A recent study published in PLOS Genetics showed that consumption of Kombucha Tea (KT) microbes (KTMs) by the model organism Caenorhabditis elegans results in a significant reduction in lipid accumulation compared to animals fed a control diet of E. coli. The study aimed to elucidate the mechanisms by which KTMs modulate host lipid metabolism.

The researchers first isolated and identified the key microbial species present in their KT culture, which included the bacterium Komagataeibacter rhaeticus, the yeast Zygosaccharomyces bailii, and the bacterium Acetobacter tropicalis. They then fed C. elegans these individual KT microbes or combinations thereof and assessed the animals’ lipid levels.

The results showed that animals consuming the full KTM consortium had the lowest lipid levels, as measured by Oil Red O and Nile Red staining, as well as biochemical quantification of triglycerides. Interestingly, the individual microbes or a minimal KTM consortium (KTM-M) were not as effective at reducing lipid accumulation, suggesting that the synergistic interactions between the different KT microbes are important for the observed metabolic effects.

Further analysis of the C. elegans transcriptomes revealed that the KTM diet specifically altered the expression of genes involved in lipid metabolism, in contrast to the control E. coli diet. Genes related to lipid catabolism were upregulated, while those involved in lipid synthesis were downregulated in KTM-fed animals. This transcriptional remodeling of metabolic pathways appears to be a key mechanism by which KTMs suppress lipid accumulation in the host.

Importantly, the study found that the KTM-mediated effects on lipid metabolism were independent of nutrient absorption, development, or reproduction, as these processes were largely unaffected by the different diets. This suggests that KTMs specifically target host metabolic pathways to drive the observed lipid-lowering phenotype.

The researchers propose that KTM consumption stimulates a fasting-like response in the C. elegans intestine by rewiring transcriptional programs to promote lipid utilisation. Specifically, KTMs upregulate a suite of lysosomal lipase genes that function in lipophagy, a selective form of autophagy that targets lipid droplets. This increased lysosomal lipase activity, coupled with a decrease in lipid droplet biogenesis due to downregulation of the dgat-2 gene, limits triglyceride synthesis and promotes lipid catabolism.

Triggering a fasting-like response to suppress lipid accumulation in humans through Kombucha Tea consumption may have significant health benefits, including weight management, improved metabolic health, stress resilience, longevity, and gut health. However, more research is needed to fully understand these effects in humans.

Reference:

DuMez-Kornegay RN, Baker LS, Morris AJ, DeLoach WLM, Dowen RH (2024) Kombucha Tea-associated microbes remodel host metabolic pathways to suppress lipid accumulation. PLoS Genet 20(3): e1011003. https://doi.org/10.1371/journal.pgen.1011003