In the Cederberg Mountains of South Africa, a spindly green shrub turns a deep reddish-brown as it dries in the sun. Within the color change, which results from natural oxidation and fermentation, scientists say, may lie a defense against one of aging’s most feared diseases.
The shrub is Aspalathus linearis, better known as rooibos, and it grows wild nowhere else on Earth. For generations, it has been South Africa’s everyday cup of tea—caffeine-free, low in tannins, and woven into family life from childhood.
Courtesy of Marthane Swart
Now scientists are taking a closer look at what’s actually in that cup, and early findings suggest its antioxidant compounds may do more than quench thirst: they may help calm inflammation, protect blood vessels, and shield brain cells from damage.
“Current research is exploring whether rooibos may help protect brain cells against the oxidative stress, inflammation, and cellular damage associated with neurodegenerative conditions such as Alzheimer’s and Parkinson’s disease,” Marthane Swart, secretariat of the South African Rooibos Council, told The Epoch Times in an email. She added that the findings so far are preclinical, meaning it isn’t yet known whether drinking rooibos tea has the same effect in people that scientists are seeing in cells and animals.
What’s in Rooibos and Why It Matters
Courtesy of Marthane Swart
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In South Africa, rooibos has also become popular among endurance athletes because it is hydrating, caffeine-free, and rich in antioxidants, Swart said. “Experimental research has also suggested that rooibos may reduce physical fatigue during repeated exhaustive exercise and may offer some protection against the effects of high-altitude exposure.”
Rooibos’ Brain Gain
A promising area of rooibos research is the brain.
Study author Taskeen Docrat believes the neuroprotective effects of rooibos are not due to a single antioxidant compound, such as aspalathin.
“The neuroprotective effects are likely due to the synergy of the entire mix of compounds present,” Docrat told The Epoch Times via email. “Rooibos contains a variety of phytochemicals, such as dihydrochalcones, flavones, and flavonols, which work together to target multiple pathways, enhancing its overall effectiveness.”
Of all the mechanisms discussed in the review, Docrat said the strongest evidence so far points to three things: rooibos’s ability to reduce inflammation in the brain, calm oxidative stress, and support healthy mitochondria, the energy-producing structures inside cells.
Studies have found that rooibos compounds can neutralize reactive oxygen species and influence how the brain processes amyloid-beta, the protein fragment thought central to Alzheimer’s disease, Docrat said.
“It directly scavenges free radicals and helps reduce protein aggregation, while also bolstering the brain’s own maintenance and repair processes. This includes enhancing antioxidant enzymes and supporting cellular processes like autophagy, which is particularly important as we age,” she said.
Most of the studies included in Docrat’s review are in cell or animal models.
“While there have been human trials confirming some benefits of rooibos related to systemic antioxidant and cardiovascular effects, there is still a need for more clinical research focused specifically on neurodegenerative biomarkers and cognitive outcomes,” Docrat said.
Red or Green: What’s the Difference?
Courtesy of Marthane Swart
Both red and green rooibos come from the same plant, Aspalathus linearis. The difference is in how they are processed after harvesting.
Traditional red rooibos is cut, bruised, and moistened, then left to oxidize, Swart said. This process changes the leaves from green to reddish-brown, giving the tea its smooth, naturally sweet flavor. The leaves are then dried in the sun.
Green rooibos skips most of that oxidation, so it stays green and tastes lighter and grassier.
Because it undergoes less processing, green rooibos retains higher levels of aspalathin and generally has greater antioxidant activity in lab tests. Red rooibos is still packed with many beneficial compounds, though—and is the version most people drink, so it’s also the most studied.
Brewing
Brewing method also makes a difference. Docrat recommends steeping rooibos in boiling water for five to 10 minutes to draw out the most polyphenols, including aspalathin. Unlike many teas, rooibos is naturally low in tannins, so it rarely turns bitter even with a longer steep.
In fact, Swart said, steeping longer tends to bring out its natural sweetness and honey-like flavor. In South Africa, it’s typically served plain or with milk, lemon, honey, or sugar, brewed strong over ice, or turned into cocktails, lattes, and a South African favorite: the “red cappuccino.”
Courtesy of Marthane Swart
Final Thoughts
Rooibos grows wild only in South Africa’s Cederberg region, and authentic rooibos is a protected product that must come from there. Its story begins with the traditional knowledge of the Khoi and San peoples and continues today through local farming communities.
“It is served in homes, workplaces, restaurants, and community gatherings and is commonly introduced from childhood, Swart said. “It is therefore both an ordinary household beverage and a distinctive expression of South African origin.”
