THE NEW ZEALAND MEDICAL JOURNAL Journal of the New Zealand Medical Association

New Zealanders’ favourite natural health products are ineffective Significant numbers of adults and children use one or more forms of complementary and alternative medicine (CAM), and the industry is worth billions of dollars globally. 1,2 There are a plethora of different therapies and products, but the vast majority are either not biologically plausible and/or not support by research evidence. e.g.,3–5 Based on feedback from talks to patient groups on the subject, from local health professionals and the media, it is apparent that some natural health products are particularly popular with the New Zealand public. These therapies and products are often advertised in local newspapers and on radio and are usually manufactured in New Zealand, which may be driving demand. They include: Colloidal silver—consists of tiny silver particles suspended in a liquid base and is taken orally, sprayed on the skin or even injected intravenously. Products are marketed as being beneficial for the immune system and for serious diseases including cancer, HIV and pneumonia. Silver does have some antimicrobial actions, but not only is there no clinical evidence of any efficacy for these serious indications, products have been shown to contain widely variable amounts of silver and can cause argyria —dangerous and untreatable silver poisoning. Deer velvet—a dietary supplement made from the antlers of deer that have been surgically removed whilst they are still growing. The idea that deer velvet has healing properties likely originates from the fact that as it is the only mammalian organ with the ability to regenerate itself, if used as dietary supplement it will confer health benefits. Very little human clinical research has been undertaken. Rescue remedy—Bach flower remedies were developed by homeopath Edward Bach who believed that he had a psychic connection to plants. He developed 38 individual flower products and one combination of 5 flower extracts called “rescue remedy”, to be used in cases of emergency and emotional trauma. Products contain tiny amounts of flower extract and it is not surprising that studies have shown no positive effects greater than placebo. 4 Arnica—Arnica is a herbal medicine used for the treatment of sprains and bruises. While there is evidence that preparations of arnica species might promote wound healing, arnica is largely sold as a homeopathic remedy which in rigorous trials is no more efficacious than placebo.6 Megadoses of vitamin C—the use of very high doses of vitamin C to treat people with cancer can be traced back to Linus Pauling's book “ Vitamin C and Cancer ”, in which he claimed that massive doses of vitamin C could help to treat cancer. However, his study was flawed and studies undertaken later at the Mayo Clinic found no benefits. More studies are ongoing, but currently the research evidence does not support this treatment and it can actually reduce the effectiveness of radiation therapy and some forms of chemotherapy. 7

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Propolis—a resin-like material from the buds of some trees which is usually obtained from beehives and therefore also contains bee products. It is taken orally or applied topically for a wide variety of conditions, most of which have no supporting evidence other than possible antimicrobial activity when applied topically. Magnets—static magnets are widely marketed for many health benefits, particularly pain relief, in many forms including mattress underlays, bracelets, necklaces and shoe insoles. The underlying theory is that they can influence blood flow by interacting with iron in red blood cells. However, iron in the blood is not in a form that can be influenced by magnets and there is no good clinical research evidence to support their use for any condition. Shark cartilage—is widely used, particularly by patients with cancer, as it is reported to have antiangiogenic and antitumour activity in vitro . However, no clinical studies have demonstrated any benefits in patient with cancer and harvesting of sharks for their cartilage is contributing to the recent dramatic decline in shark populations. Lemon detox diet—This is a form of juice fast. In the ‘classic’ version, all meals are substituted with the lemon detox drink for 5–10 days and the fasting is claimed to ‘cleanse’ the body of accumulated toxins. However there are no clinical studies to support this theory and there are potentially serious consequences from prolonged fasting, severe caloric restriction and excessive concurrent fluid intake. 8 Therefore, despite their popularity, some of the most popular natural health products used by people in New Zealand are at best a waste of time and money, and may also be harmful. Shaun Holt Tauranga Sarah Jeffries Wellington Andrew Gilbey Palmerston North References: 1. Nahin, RL, Barnes PM, Stussman BJ, Bloom B. Costs of Complementary and Alternative Medicine (CAM) and Frequency of Visits to CAM Practitioners: United States, 2007. National health statistics reports; no 18. Hyattsville, MD: National Center for Health Statistics. 2009. 2. Ernst E. Prevalence of use of complementary/alternative medicine: a systematic preview. Bull World Health Organ. 2000;78:252–7. 3. Ernst E, Pittler MH, Wider B, Boddy K. The desktop guide to complementary and alternative medicine. 2nd edition. Edinburgh: Mosby/Elsevier; 2006. 4. Armstrong NC, Ernst E. A randomized, double-blind placebo-controlled trial of a Bach Flower remedy. Complement Ther Nurs Midwifery 2001;7:215–221. 5. Creagan ET, Moertel CG, O’Fallon JR, et al. Failure of high-dose vitamin C (ascorbic acid) therapy to benefit patients with advanced cancer. A controlled trial. N Engl J Med. 1979;301:687–90. 6. Ernst E. Pittler MH. Efficacy of homeopathic arnica: a systematic review of placebo- controlled clinical trials. Arch Surg 1998;133:1187–1190

7. Holt S. Hype around high-dose vitamin C is unjustified [letter]. New Zealand Medical Journal 15 October 2010;123(1324). http://journal.nzma.org.nz/journal/123-1324/4404/content.pdf 8. Detox diets Mayo Clin Womens Healthsource. 2009 Jul;13(7):8.