Health benefits of Rooibos

The health benefits of tea are constantly mentioned in the media and a lot of people seem to start drinking tea (especially green tea and herbal teas) for health reasons. So, from time to time, I gather and review the research that is published.

Rooibos Farm (source)

Rooibos Farm (source)

Rooibos is a caffeine-free tisane that comes from the leaf of Aspalathus linearis. Since it does not come from Camellia sinensis it is not a real tea so we call it a herbal tea or tisane. Traditional medicinal uses of rooibos have included alleviation of infantile colic, asthma, allergies, dermatological problems, digestive discomfort and anxiety.

Many studies have been done on the antioxidant content of Rooibos. Marnewick found that a 200ml serving of Rooibos has 58.5 – 68.9mg of pholyphenol antioxidants (depending on amount of leaves used and brewing time). Studies on the chemical constituents of the antioxidants in Rooibos have shown the presence of nothofagin, aspalathin and isoorientin, orientin, rutin and several other flavonoids and phenolic acids. The types of polyphenols in Rooibos are different to those in Green tea and Black tea and in particular, the antioxidant aspalathin can not been found in any other natural sources besides Rooibos. Researchers have found that “an aspalathin-enriched extract of green rooibos is able to lower raised glucose levels in the blood of diabetic rats” (source).

Two of Rooibos’s antioxidants (quercetin and luteolin) have been shown, in vitro, to induce the death of cancer cells (in vitro just means that the tests were carried out in a controlled environment outside a living body, e.g. in a test tube). Rutin has been found to prevent the formation of thrombosis (blood clots) in mice and orientin has been associated with a reducing damage to the bone marrow and gastrointestinal tract after mice were exposed to radiation.

Aspalathus linearis

Aspalathus linearis (source)

Although, the antioxidant content of Rooibos is well documented and there are many laboratory results on the benefits of those antioxidants, I found it very difficult to find scientific, peer-reviewed articles on human studies involving Rooibos. One paper, published in the Journal of Ethnopharmacology, looked at the effect of Rooibos on specific parameters for adults at risk of developing heart disease. The results were positive and Rooibos significantly improved the lipid profile and the redox status. However, just 40 participants were involved in the study so presumably it would need to be repeated with a much larger group before it could be cited as conclusive evidence.

Rooibos has long been used to soothe colic in babies but the tea gained particular attention in the late 1960s when a South African woman, Annique Theron, found that it eased her infant’s colic. The story goes that she found no documentation on the benefits of Rooibos so she began her own experiments with babies who had colic and allergies. She concluded that Rooibos helped with the symptoms and she published a book in 1970 entitled “Allergies: An Amazing Discovery”. Rooibos seems to be still recommended by South African physicians in the treatment of colic even though the scientific evidence as a treatment does not seem to exist. Similarly, there is no scientific research into Rooibos as a treatment for skin allergies or digestive problems but its use as a treatment for both seem widely accepted.

Rooibos NaturalSo what’s the bottom line on the health benefits of Rooibos? Well, Rooibos is naturally caffeine-free, calorie-free, low in tannins and rich in antioxidants. Some lab and mouse work have been done on the specific benefits of the antioxidants in Rooibos but research on human models is scant. I think Ferreira et al put it best when he said “the growing body of evidence pointing towards the therapeutic value of Rooibos tea gives a considerable degree of credibility to the anti-ageing claims, but expectations of a healthier life rather than increasing lifespan would perhaps be a more realistic outlook”.

Rooibos health updates

I have written previously about some of the research on rooibos but since then I came across a few new pieces:

  1. A study looking at the potential of Rooibos to increase the shelf life of Ostrich meat patties!
  2. A piece of on-going research involving the influence of Rooibos on prostate cancer.
  3. A study on the liver-related benefits of Rooibos and Red Palm Oil that was published in Evidence-Based Complementary and Alternative Medicine.

The press releases around the last one grabbed my attention by saying that this research proved that rooibos could improve liver function and protect against oxidative damage to the liver.

Rooibos Natural

 

The inclusion of Red Palm Oil (RPO) in the title sent me off on a tangent to find out more about it. This in turn led to a diversion down the road of Palm Oil and Oxidised Palm Oil. Several hours later I had lost most of Saturday and was so far down a byroad of nutritional science that I didn’t think I would ever find my way back.  But the detour did turn up some interesting information albeit mostly unrelated to rooibos or tea.

It seems that palm oil comes from the palm fruit and is popular with food manufacturers because it is cheap and after processing has a long shelf life, is odourless and is solid at room temperature.  Oxidised palm oil is commonly used in food products and the oxidation seems to be responsible for the generation of toxicants and the introduction of “reproductive toxicity and toxicity of the kidney, lung, liver and heart” (Edem, 2002).

Red palm oil on the other hand comes from the same part of the palm tree but is red in colour from its high concentration of carotenes. Unprocessed, it contains high amounts of antioxidants and is associated with cardiovascular and nutritional benefits. At moderate levels, RPO is believed to promote the utilisation of nutrients, improves immune function and activate hepatic drug metabolising enzymes (Oguntibeju, 2009). Nutritional supplementation seems to show promise in lowering LDL cholesterol and experiments on rats show improved protection of the heart. [For entertainment see Dr Oz’s dramatic endorsements of RPO].

This new rooibos study worked from the basis that both rooibos and RPO had been shown to be liver-protective and it aimed to investigate if the positive effect could be heightened by combining rooibos and RPO. The results suggested that rooibos and RPO both protect the liver but the level of protection was only equal to that of either rooibos or RPO so a synergy in the combined protective effects could not be shown. Unfortunately, the study was carried out on rats so we still can not say for sure that a similar liver-protection effect happens when humans drink rooibos.

In fact, the only report involving rooibos and human liver that I found was a report in the Eur J Clin Pharmacology about a 42 year old patient with a previous medical history who experienced signs of liver damage after starting to drink rooibos. Clearly, a single case is not a basis for any kind of conclusion but it does indicate once again the need for human studies to confirm health benefits.