Tea may be drunk hot or cold but, either way, it’s made by infusing the dried crushed leaves of the tea plant in boiling water. Rooibos (pronounced “roy-boss”)1 is made from the fermented leaves of the Aspalathus linearis, which is native to South Africa.2 According to the South African Rooibos Council,3 it’s not a true tea but, rather, a fermented and dried herb.
The tea is red in color and is sometimes referred to as African red tea, or red bush tea.4 It’s been a popular beverage in Africa for centuries and has a sweet honey taste with a rich red hue. Green rooibos is green-brown in color and has a grassy flavor similar to green tea.
Both red and green rooibos teas are caffeine-free and have low levels of tannins, which are substances that may trigger migraines or allergies in those who are sensitive.5 More recently it’s gained popularity with tea drinkers as it is a palatable alternative to green and black tea, both of which can have a bitter taste.
The methods used to make organic rooibos tea are similar to those used more than 100 years ago. After being harvested, the stems and leaves of the Aspalathus linearis are bruised and left to ferment and oxidize.6
The fermentation process gives the tea its distinct reddish-brown color. Keep in mind, though, there are other types of beverages also called red tea that are not rooibos, including some black teas and hibiscus tea. When the tea is not fermented, it’s characterized by a green color and a grassy flavor.7
Although it undergoes less processing, green rooibos tea is often more expensive than the red variety and contains higher amounts of antioxidants.8 The flavor of red rooibos makes it perfect for a dessert tea,9 and significantly healthier than sugar-laden drinks and cakes.
History of rooibos tea
Botanists first identified rooibos tea in 1772, but it was a housewife10 named Annique Theron who put South Africa’s red tea on the map when she discovered it could calm and soothe her colicky baby when she added it to her breastmilk. She was subsequently awarded an honorary doctorate for her discovery. The South African Rooibos Council credits Theron — who later became a businesswoman selling health and beauty products — with popularizing what has become a go-to remedy.11
The tea began gaining popularity in the U.S. during World War II, a time when importing tea from Asian countries was nearly impossible. It became an excellent alternative, but the price remained high as the seeds were scarce.12
In 1930 a local medical doctor and an amateur botanist discovered the secret of germinating the seeds, and together with a commercial farmer, developed cultivation methods that allowed them to produce rooibos on a larger scale.13
In 1980, Japanese and American scientists discovered the tea contained a powerful antioxidant and, in 1995, a medical doctor together with a South African research company discovered the tea had antiviral, anti-allergic, anti-inflammatory and antibacterial properties.14 By 2003, rooibos tea was fully established and growing in popularity in the U.S. and Europe.
Rooibos tea flavor varies depending upon botanical content of the herb
While there’s a distinct flavor difference between red and green rooibos tea, scientists have also found a compound that contributes to the taste and feel of fermented rooibos tea. The compound, Z-2-(?-d-glucopyranosyloxy)-3-phenylpropenoic acid (PPAG), has been isolated from unfermented plant material.
Researchers found a similar compound, and analysis of the leaves of a large number of plants showed PPAG was not uniformly present in detectable quantities in the leaves of different plants on the commercial plantation.15
During fermentation, there was a large variation in PPAG, subsequently found in infusions and food grade extracts. Researchers found it adds a slightly bitter to astringent taste to the tea, which may account for the difference in flavor in rooibos tea purchased from different manufacturers.16
This rare acid is one of the major constituents in fermented infusions and has been shown to enhance insulin release and glucose uptake in muscle cells. The results of one study17 suggest the liver is the primary target organ for bioactivity and describes how PPAG increases glucose uptake in a test tube and improves glucose tolerance in rats.
Hypoglycemic effect helps stabilize blood sugar
Rooibos has a flavonoid profile distinctly different from those found in Camellia sinensis, from which traditional tea is derived. In addition to PPAG, rooibos tea also contains aspalathin, a component of the Aspalathus linearis plant. The effects of aspalathin, found in green rooibos tea, were evaluated in a study published in Phytomedicine.18
Scientists looked at glucose metabolism in vitro and in vivo. In the first stage they examined the effect on glucose uptake on cultured cells and insulin secretion from pancreatic beta cells. Subsequently, the researchers used mice with Type 2 diabetes and found aspalathin significantly increased glucose uptake and insulin secretion in a dose-dependent manner.19
A second study20 found aspalalinin, which currently has only been isolated in rooibos, and a variety of other flavonoids and flavanols, including quercetin and chrysoeriol, have been isolated from the red bush. The process of fermentation gives the tea its unique reddish-brown color.
However, tea brewed from unfermented green rooibos is reported to have higher antioxidant capacity and richer bioactive constituents.21 This rich source of unique antioxidants may play a role in exerting beneficial effects against the pathophysiology of diabetes and diabetic complications.
When fermented and administered to diabetic rats, rooibos reduced biochemical markers characterizing liver toxic effects and suppressed lipid peroxidation and enhanced glutathione-peroxidase in the blood and liver.22
Other studies have confirmed the aspalathin in rooibos can modulate glucose metabolism, suppress elevated fasting blood glucose and alleviate impaired glucose tolerance.23
Antioxidant levels of rooibos tea may contribute to multiple health benefits
Antioxidants are sometimes called free radical scavengers as they are substances that may prevent or slow damage to your cells triggered by free radicals. Plant-based antioxidants are phytonutrients or plant-based nutrients.24 Free radicals are waste products normally produced by your cells during the process of metabolism.
Your body needs a way to remove free radicals efficiently or oxidative stress may result, harming cells and increasing your risk of disease. Oxidative stress has been linked to heart disease,25 cancer,26 arthritis,27 stroke28 and neurological disease.29 Antioxidants help neutralize free radicals, which ultimately helps to boost your overall health.
Free radicals may be produced during mitochondrial activity, excessive exercise, tissue trauma and exposure to smoke, environmental pollution or toxic chemicals. A plant-based diet protects against chronic stress by increasing your antioxidant content.30
One way of evaluating the amounts of antioxidants found in your food, especially fruits, is by slicing them and exposing the content to air.31 If they turn brown, they’re oxidizing and likely don’t have a lot of antioxidants. Adding lemon juice, high in vitamin C, may keep your food from oxidizing, and may do the same thing inside your body.32
The fermentation process causes some loss of antioxidants, which is why green rooibos contains higher levels of polyphenols. Rooibos tea contain flavonoids, phenolic acid, quercetin and luteolin, all of which are powerful antioxidants. According to the American Botanical Council,33 a 6-ounce serving of rooibos tea may have up to 80 milligrams of total polyphenols.
Anti-inflammatory properties contribute to pain relief
Inflammation and the release of cytokines is an attempt by your body to protect itself and begin the healing process. Infections, wounds and tissue damage may trigger an inflammatory response and subsequently pain.34
Cytokines are one measurement of inflammation in the body and may be linked to the severity of pain.35 In several studies,36 researchers found baseline elevations of proinflammatory and anti-inflammatory cytokines, and when proinflammatory cytokines markers were higher it was associated with a greater degree of pain.
Research published in the Journal of Inflammation37 found the use of rooibos tea had an anti-inflammatory effect on a systemic level. Another animal study38 concluded rooibos tea may prevent DNA damage and inflammation via antioxidative activity.
Since the tea is free of caffeine, the researchers suggested routine consumption may be safe and useful in reducing oxidative stress in children. Another study39 concluded rooibos tea had dual function on inflammation and had the ability to promote the production of nitric oxide.
More rooibos tea health benefits are related to anti-aging factors
The use of rooibos tea has been cited for being helpful in lowering blood pressure and relaxing tense muscles.40 This is likely related to the increased nitric oxide production after consumption. In one study,41 cultured cells from human umbilical veins were incubated with rooibos tea and the cells were examined for their effect on angiotensin converting enzyme and nitric oxide.
After incubation for 10 minutes there was a significant dose-dependent inhibition on angiotensin-converting-enzyme with green tea and black tea but not rooibos tea. After 24 hours, there was a positive effect on the production of nitric oxide with rooibos tea.
In an animal study,42 researchers found rooibos tea had the ability to reverse stress-related metabolites and restore stress-induced protein degradation. In a human study43 using 17 healthy volunteers, researchers evaluated oral intake of a single dose of rooibos tea and found it had cardiovascular effects through the inhibition of angiotensin converting enzyme activity.
A literature review44 looking at past studies found differences and inconsistencies in the amount of nitric oxide produced. The scientists attributed this to common occurrences from in vitro and in vivo studies, and differences in the concentrations tested.
According to the researchers, another factor contributing to such differences may have been related to variations in the different batches of rooibos tea sampled, as they found chemical composition differed depending on the botanical species, the part of the plant used, storage methods and agricultural practices. They concluded that while nitric oxide was produced, there was a variation in the amount.45
In addition to cardiovascular health, rooibos tea has also been associated with reducing oxidative stress in the liver46 and protecting cells against the natural aging process. Antibacterial compounds, antioxidants, vitamins and minerals all work to help improve skin texture, quality and health.
The reduction in systemic inflammatory response47 also helps protect your skin, and according to Reader’s Digest, acne and eczema sufferers have reported rooibos tea helps improve these conditions.48 Rooibos tea is also naturally high in calcium, manganese and the antioxidants orientin and luteolin, which help maintain good bone structure and strong teeth.49
Rooibos may improve male fertility
Although researchers are coming to a consensus that men in America and Europe are experiencing a drastic decline in fertility,50 they have not agreed on a single cause. Studies released in 2018 support past research finding motility, or the ability of the sperm cells to swim, has declined in the past decade.51
In other studies,52 researchers have found the application of rooibos tea to animal semen in vitro increased sperm velocity, membrane integrity and protected the structure.
In an in vivo study53 on male rats, researchers found treatment with rooibos improved sperm concentration, viability and motility, which they hypothesize might have been attributed to the high level of antioxidants. A third study54 using rats with diabetes found the application of rooibos improved sperm health, including velocity and motility.
How to store, brew and drink rooibos tea
As with any other herb, rooibos should be stored properly to maintain freshness and viability. While it may not ever go “bad,” it may get stale and taste weak and musty. Be sure to purchase your rooibos from a reputable company that can tell you how the tea was processed and packaged and when it was harvested.
Since it is oxidized in a fashion similar to black tea, it technically stays fresh for up to two years when stored correctly.55 Take care to keep it in a cool dark place, away from light, oxygen, moisture and any fragrant foods, such as coffee or spices.
To brew a great cup of rooibos tea, use fresh, pure filtered water. If you purchase a good quality loose leaf tea it may be infused at least twice. Your tea likely came with specific recommendations for brewing you should use. Generally, 2 grams of loose tea leaf for every 8 ounces of water will give you a tasty cup.
Rooibos is infused at temperatures from 200 to 212 degrees Fahrenheit. Cover the pot while the tea is infusing to keep the heat inside the vessel. Taste it after the recommended time and decide if you’d like it a little stronger. Unlike other traditional teas, rooibos will not taste more astringent or bitter the longer it’s in hot water, it only gets stronger and more flavorful.56
Some recommend adding milk or cream with the tea.57 However, researchers have found simultaneously ingesting dietary proteins, such as casein found in milk or cream, reduces the bioavailability of the catechins found in the tea,58 and therefore may reduce its health benefits.