Rooibos tea is made from the needle-like leaves of a small shrub that grows in the "red bush" scrub of the Western Cape of South Africa. Although it is called tea, rooibos is an herbal tea and not a "true" tea from the Camellia sinensis plant. In contrast, rooibos, or Aspalathus linearis, is a member of the pea family. Rooibos does provide some of the same benefits as black and green teas in terms of antioxidant content, but it has fewer tannins and no caffeine. However, rooibos tea may exert estrogenic effects and interfere with certain medications, so check with your doctor before indulging.
Background
In South Africa, rooibos tea plays a role in the traditional medicine of the region, where it is used to treat infant colic and address inflammatory disorders such as asthma, hay fever, acne, eczema and psoriasis. Rooibos is also reputed to help regulate blood sugar, lower cholesterol and prevent or treat certain types of cancer. The parts of the plant harvested for medicinal purposes are the leaves and twigs.
Pharmacology
Rooibos contains several flavonoid glycosides, such as quercetin, orientin and isoorientin, but the most active are aspalathin and nothofagin. The plant also contains protein and minerals, various polyphenols and volatile oils, including damascenone, geranylacetone, guaiacol and beta-phenylethyl alcohol. A study published in "Analytical and Bioanalytical Chemistry" in July 2011 shows that rooibos polyphenols reduce blood levels of triglycerides and cholesterol. Previously, a January 2011 study in the "Journal of Ethnopharmacology" found that drinking rooibos tea significantly reduces LDL cholesterol while increasing HDL cholesterol, which prompted the study authors to conclude that rooibos may reduce the risk of heart disease.
Adverse Effects
According to the Memorial Sloan-Kettering Cancer Center, aspalathin, a main component of rooibos, is absorbed as a carbohydrate in the intestines and metabolized in the liver. In a letter to the editors of the "European Journal of Clinical Pharmacology," Marjatta Sinisalo and colleagues describe a case report in which a 42-year old woman suffered liver damage after drinking rooibos tea, which suggests possible hepatotoxic effects. Also, the June 2006 issue of "Biological and Pharmaceutical Bulletin" includes a report that of 25 rooibos compounds isolated and analyzed, three demonstrated estrogenic activity. This means that you should not drink rooibos tea if you have a history of a hormone-driven cancer.
Drug Interactions
Compounds in rooibos tea enhance immune function by stimulating an increased production of specialized signaling molecules called interleukins, including IL6 and IL10. These phytochemicals also block the activity of an enzyme responsible for producing inflammation called COX-2. Although this activity contributes to the positive anti-inflammatory and antioxidant effects of the tea, it presents a possible contraindication for people undergoing treatment for cancer with chemotherapy agents. If this describes you, talk to your doctor about your consumption of rooibos tea while in treatment.
References
- "Physicians' Desk Reference for Herbal Medicines"; Thomas Brendler, et al.; 2007
- Memorial Sloan-Kettering Cancer Center: Rooibos Tea
- "Analytical and Bioanalytical Chemistry"; Identification of Phenolic Compounds in Aqueous and Ethanolic Rooibos Extracts (Aspalathus linearis) by HPLC-ESI-MS (TOF/IT); I. Iswaldi, et al.; July 2011
- "Journal of Ethnopharmacology"; Effects of Rooibos (Aspalathus linearis) on Oxidative Stress and Biochemical Parameters in Adults at Risk for Cardiovascular Disease; J.L. Marnewick, et al.; January 2011
- "European Journal of Clinical Pharmacology"; Possible Hepatotoxic Effect of Rooibos Tea: A Case Report; M. Sinisalo, et al.; April 2010
- "Biological and Pharmaceutical Bulletin"; Phytoestrogens from Aspalathus linearis; N. Shimamura; June 2006
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