Rooibos is a type of tea made from the dried leaves of the rooibos plant and is touted for its antioxidant properties.
While rooibos has antioxidant potential, it does not appear to be as potent as its counterpart, green tea, due to a lack of catechins — phenolic compounds present in green tea, known to have powerful antioxidant activity.
Although less potent than green tea catechins, rooibos is a definite contender as an antioxidant supplement.
Native to South Africa, rooibos tea is rich in antioxidants, especially the polyphenols aspalathin and nothofagin. Growing in vitro and animal studies show that this plant improves immune function, exhibits an anti-inflammatory effect, may prevent oxidative stress and plays a role in alleviating symptoms of type-2 diabetes (1).
Rooibos may be beneficial in improving cholesterol levels. Plant-derived polyphenols are increasingly being investigated as a possible way to provide safe and effective alternative treatments for lowering cholesterol. In fact, according to the findings of a study published in the medical journal, Phytomedicine, adding polyphenols to the daily diet is likely to help in the overall management of metabolic diseases.
Metabolic disease is a cluster of conditions — increased blood pressure, high blood sugar, excess body fat around the waist and abnormal cholesterol or triglyceride levels — that occur together, increasing the risk of heart disease, stroke and diabetes (2).
In another study, rooibos consumption (six cups of fermented/traditional rooibos daily for six weeks) showed the potential to improve the lipid profile in adults at risk for developing cardiovascular disease.
Results revealed the following: significant decreases in plasma markers of lipid peroxidation after rooibos consumption; decreased serum LDL-cholesterol (“bad cholesterol”) and triacylglycerols (a triglyceride); and increased HDL-cholesterol (“good cholesterol”) 3.
This effect, however, was not seen in healthy adults.
Rooibos is high in antioxidants. An acute intervention study was performed with 15 healthy volunteers to assess the effect of drinking rooibos tea on total antioxidant capacity. The participants consumed 500ml of either water, unfermented or fermented rooibos teas.
Plasma antioxidant capacity increased significantly with both teas, reaching a peak at one hour post-consumption (4).
Rooibos may have a hypoglycemic effect. In a recent study, the effects of aspalathin (a rooibos tea component) on glucose metabolism were evaluated in vitro and in vivo (mice study). According to the results published in Phytomedicine, aspalathin dose-dependently and significantly increased glucose uptake and significantly increased insulin secretion.
Dietary aspalathin also suppressed the increase in fasting blood glucose levels of diabetic mice for five weeks (5).
In a study on the effects of rooibos on oxidative stress and biochemical parameters in adults at risk for cardiovascular disease, researchers found that drinking tea decreased blood glucose by 14.4 percent.
In another study, aspalathin supplementation dose-dependently increased glucose uptake, significantly suppressed the increase in fasting blood glucose levels and improved glucose intolerance (6).
More studies in humans are needed to confirm this benefit.
Rooibos may be an effective HIV treatment. A polysaccharide extracted from rooibos leaves has been shown to have strong anti-HIV activity. According to one study, the polysaccharide almost completely inhibited the binding of HIV-1 to MT-4 cells — cells that are highly susceptible to and permissive for HIV.
Researchers note that the polysaccharide extracted with 1 percent sodium carbonate from rooibos leaves was effective, while hot water extract of rooibos was not (7).
Rooibos may have chemoprotective activity. The chemoprotective properties of unfermented and fermented rooibos, along with honeybush herbal teas, and green and black teas were recently investigated against liver cancer in rats.
Unfermented rooibos (as opposed to fermented) significantly reduced the total number of microscopic tumor cells (8).
Rooibos may have liver protective effects. To evaluate these effects, researchers induced hepatotoxicity in rats in a recent study. The goal of the study was to compare the protective effects of an aqueous rooibos extract, red palm oil or a combination of both on the liver.
Results suggest that rooibos and red palm oil, either supplemented alone or in combination, are capable of alleviating hepatotoxicity. The mechanism of this protection may involve inhibition of lipid peroxidation and modulation of antioxidants enzymes and glutathione status; glutathione is an important antioxidant in the body (9).
Rooibos may improve male reproductive function. Due to its antioxidant activity, rooibos is believed to improve sperm function. To test this hypothesis, male rats were given 2 percent or 5 percent rooibos tea for 52 days.
Researchers noted that treatment with rooibos improved sperm concentration, viability and motility. However, prolonged exposure of rooibos might result in subtle structural changes in the male reproductive system, which can impair fertility (10).
Rooibos may improve symptoms of andropause, a condition that is associated with the decrease in the male hormone testosterone. Andropause is a term used to describe age-related hormone changes in men.
A combination supplementation of 200-400mg of dandelion and rooibos water extracts (known as CRS-10) over four weeks improved the quality of life among aging male respondents, according to a clinical survey.
The results indicate the potential of CRS-10 as a safe and efficacious natural substance for reducing or alleviating andropause symptoms; such symptoms include changes in sexual function, changes in sleep patterns, physical changes (increased body fat, reduced muscle bulk and strength, and decreased bone density) and emotional changes (decrease in motivation or self-confidence). 11
In general, drinking the tea in moderation is safe. Intake of large amounts of rooibos may harm liver and kidney function (12).
According to Memorial Sloan Kettering Cancer Center, due to compounds isolated from rooibos leaves demonstrating estrogenic activity, patients with hormone-sensitive cancers should use caution before taking rooibos (13).
More studies are needed to gather enough information to recommend the optimal dosage of rooibos as a tea or as a supplement.
It appears, however, that the minimum effective dose in humans has been a cup of tea brewed from 750mg of the plant.
Rooibos is plant that is touted for its antioxidant properties. It is typically consumed by steeping dried leaves to make tea. While it lacks the antioxidant-rich catechins found in green tea, it is rich in the polyphenols aspalathin and nothofagin, which are also known antioxidants.
Research demonstrates its potential to treat a wide range of conditions, including high cholesterol, type-2 diabetes, HIV and male infertility.
Some studies show its liver protective potential and the ability to improve symptoms of andropause, a condition that is associated with the decrease in the male hormone testosterone.
While these early results are promising, many more in-depth human studies and clinical trials are needed.