I have written previously about some of the research on rooibos but since then I came across a few new pieces:
- A study looking at the potential of Rooibos to increase the shelf life of Ostrich meat patties!
- A piece of on-going research involving the influence of Rooibos on prostate cancer.
- 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.
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.