Kombucha

Kombucha is the top-selling fermented beverage in U.S. supermarkets, converting skeptical consumers with its approachable tart and effervescent flavor profile — significantly more accessible than kefir or kimchi. A 2024 controlled human study demonstrated that daily consumption for four weeks shifted gut bacteria toward SCFA-producing Bifidobacterium and Prevotella, marking it as the only recent well-controlled human microbiome study on kombucha. Its polyphenol content stands at 412 mg GAE per liter — 2.3 times higher than the black tea it is brewed from, indicating the SCOBY fermentation process concentrates antioxidant compounds that act as prebiotic substrates for Bifidobacterium and Lactobacillus.