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At the centre of a great, often-acrimonious debate that is currently raging in the scientific world, is a shrub that grows in South Africa. It is suggested that Sutherlandia (or "cancer bush") has both positive health benefits and potential toxicity.
Two sides to the story
On the one hand, there are South African scientists of good standing at recognised scientific institutions such as the Universities of Stellenbosch, Pretoria and RAU, who are studying Sutherlandia and its health benefits.
Dr Carl Albrecht, a well-known cancer researcher, is of the opinion that Sutherlandia has potential for healing. On the other hand, there are individuals such as Stuart Thomson, the Director of the Gaia Research Institute, who slates this plant as potentially harmful and life-threatening.
When such controversies emerge, the public is often confused and not able to form an opinion. What is true of Sutherlandia? Is it a boon to people suffering from cancer, Aids or TB? Or is Sutherlandia toxic and dangerous?
At the moment, it is not easy to try and clear up this controversy. The problem is that there is not sufficient solid research evidence to prove either the case for, or the case against Sutherlandia.
However, it may be a good idea to consider both sides of the story and then try to reach some conclusions.
Negative arguments
Stuart Thomson, who is probably one of the most vociferous critics of Sutherlandia and investigations into its use as a cure for cancer and Aids, argues that there is a "total absence of scientific evidence" to support claims that Sutherlandia has anticancer and immune-stimulating properties.
He states that Sutherlandia contains a compound called canavanine, which is an inhibitor of an enzyme known as nitric oxide synthase. Thomson alleges that South African researchers believe that this inhibitory activity will prevent tumour growth and boost immunity.
However, Thomson points out that the opposite is actually true, namely that this enzyme should be boosted to produce the compound nitric oxide to prevent tumour growth.
A recent article published in the CME journal reported that two African herbal medicines, Sutherlandia and African potato, which are widely used on this continent to treat HIV-positive people, have been shown to interact significantly with antiretroviral medications.
Mills and coauthors (2005) have cautioned patients not to use these herbal medicines together with antiretrovirals as this could lead to early inhibition of drug metabolism and later decrease the efficacy of the antiretrovirals.
Positive arguments
In a personal communication, Dr Carl Albrecht stated that Thomson's emphasis on canavanine is misplaced. He points out that many plants, including alfalfa, contain this compound, without causing harm to animals or humans who consume the plants.
He believes that the canavanine content of Sutherlandia is so low that "it is of no consequence", and that the medicinal properties of Sutherlandia are not determined by its canavanine content.
Researchers at the University of Stellenbosch have found that Sutherlandia SU1, a variety of the plant that is cultivated by the Phyta Nova company in Cape Town, has a positive effect on the body's stress hormones.
Prof Kathy Myburgh of the Department of Physiological Sciences at Stellenbosch, says that their laboratory found evidence of Sutherlandia's stress-relieving properties, particularly in situations where individuals are exposed to chronic stress.
The Department of Pharmacology of the University of Pretoria also tested the SU1 variety of Sutherlandia and found it to be a highly potent antioxidant. Prof Connie Medlen of UP, states that "This preliminary finding may indicate that Sutherlandia could potentially be of benefit in the treatment of diseases associated with the over-production of oxidants" (e.g. asthma, allergy, autoimmune diseases and infectious diseases such as TB and Aids).
Dr Albrecht also pointed out that Sutherlandia has been used as a tonic in South Africa at least since 1895, when it was first mentioned in a book by Andrew Smith. Smith already listed Sutherlandia tea as an anticancer agent in the 19th century.
Dr Albrecht countered Stuart Thomson's allegations that "12 000 black South Africans are killed by this 'medicine' every year". He pointed out that Phyto Nova has to date sold close to 200 000 containers of Sutherlandia tablets – not one case with side effects has been reported.
Dr Albrecht stressed that additional scientific research is required to answer many of the as yet unknown questions about Sutherlandia. This stands to reason if we keep in mind that any drug that is launched on the market has to be subjected to exhaustive tests to define how it works, what side effects it may cause, what other drugs it may interact with and which members of the population should not use the drug.
Until similar tests have been completed for Sutherlandia, no one can say with certainty that Sutherlandia is a cure or a prophylactic for cancers, HIV or TB, or what its side effects are.
Conclusions
At the moment, we don't know enough about Sutherlandia and the most important aspects of its use as an anticancer or HIV medication. We do need additional research to clear up the controversies and spell out clearly if Sutherlandia has any merits, if it is potentially toxic, or if it is the long-awaited cure for Aids.
In view of the study by Mills and coworkers (2005), I would suggest that patients with
HIV or Aids using antiretroviral medication should not use any herbal medicines that may interfere with the effect of these drugs. The same applies to vulnerable population groups such as pregnant and nursing mothers, young children and anyone who is debilitated.
Let's wait and see what the researchers come up with before we start recommending Sutherlandia for each and every disease and condition. – (Dr Ingrid van Heerden, DietDoc)
(References: Albrecht C (2005). Personal communication; Mills E et al (2005). AIDS, Vol 19:95-97 as reported in CME (2005), 23(6):317; Thomson, S (2005). Sutherlandia Immuno Pseudo-Science at www.gaiaresearch.co.za/sutherlandia )
