Fermented Rooibos Calms the Gut Like a Steroid. Unfermented Strengthens the Wall.
A three-year Cape Peninsula University of Technology study on gut cells found fermented (red) rooibos eased inflammation about as well as a steroid drug, while unfermented (green) rooibos strengthened the intestinal barrier instead.
Fermented rooibos eased gut inflammation about as well as a steroid drug in a new laboratory study, and unfermented rooibos protected the gut differently, by reinforcing its lining, researchers reported.
The three-year study was led by Mariska Lilly, a senior researcher at the Cape Peninsula University of Technology. It tested both forms of the red bush on intestinal cells taken from pigs, whose gut lining closely resembles a human's.
Researchers treated the cells with a rooibos extract for 24 hours, then exposed them to a bacterial toxin for another 24 hours to trigger inflammation, and measured how the cells responded.
Fermented, or red, rooibos worked best against the inflammation itself. At the concentrations tested, it suppressed the inflammatory response about as well as dexamethasone, a steroid drug already prescribed for inflammatory gut conditions, the study found.
Unfermented, or green, rooibos worked on a different problem. It raised production of the proteins that hold the gut lining's cells tightly together, the barrier that keeps unwanted substances from leaking through what is sometimes called a "leaky gut."
The two forms differ mainly in processing, not origin: red rooibos is left to oxidize, and drying the leaf quickly instead is what keeps green rooibos green. Lilly and her co-authors, Shana De Bruyn-Orr, Stefan Abel, and Mariam Rado, published the results in the journal Food Chemistry Advances. They pointed to the two extracts' different balance of plant compounds, among them aspalathin, rooibos's own antioxidant, to explain why the effects split rather than stacked.
Real cells in a dish are not a real cup, and the gap between them is exactly what the Ministry declines to paper over. Lilly receives research funding from the South African Rooibos Council, a fact she disclosed herself when she wrote up the findings for the academic outlet The Conversation. Human trials would still be needed to confirm either effect in a person drinking the tea, she wrote, describing rooibos as "a natural substance that helps to protect your body's cells from damage caused by harmful molecules" and, on the evidence so far, "a low-risk addition to a healthy lifestyle."
Sources: Mariska Lilly, South Africa's rooibos tea: can it improve digestion?, The Conversation; Shana De Bruyn-Orr, Stefan Abel, Mariam Rado, and Mariska Lilly, Modulating the anti-inflammatory and barrier protective effects on intestinal epithelial cells utilizing an aqueous Aspalathus linearis extract in vitro, Food Chemistry Advances.