A TV investigation apparently debunking homeopathy has sparked controversy following claims that its key experiment was fundamentally flawed.
Amid a fanfare of publicity, the flagship BBC science programme Horizon last month broadcast 鈥淗omeopathy 鈥� the Test鈥�. It revealed the results of the programme鈥檚 own investigation into the claims for this highly popular form of alternative medicine. But critics insist the study was always too small to give definitive results either way.
Homeopathy claims to treat a host of ailments with extremely dilute preparations of certain compounds. The method is regarded with deep scepticism by mainstream scientists, as many of the medicines are unlikely to retain even a single molecule of the original compound.
Advertisement
Advocates argue that the water may retain a 鈥渕emory鈥� of the compound鈥檚 original presence. In particular a French researcher, Jacques Benveniste, claimed homeopathic solutions could activate basophils, a type of blood cell involved in allergic reactions.
The idea was widely thought to have been debunked in 1988, following an investigation by Nature. But since then, other teams have claimed small positive results. Some studies used thousands of samples, but counted cells by eye, which critics claim is unreliable. So Madeleine Ennis of Queen鈥檚 University of Belfast Medical School, who was involved in one of the larger trials, carried out a smaller study using automated counting and saw the same small effect.
The Horizon team set out to replicate her findings and settle the issue, employing state-of-the-art equipment and independent researchers. They compared 40 homeopathic samples with water controls, and found no evidence of any effect on the cells.
While sceptics seized on the result as proof that homeopathy is nonsense, the study itself has come under attack for being too small to have any hope of confirming the size of effect seen in previous studies. Even Ennis, who is an avowed sceptic, says the Horizon experiment was incapable of making any kind of definitive conclusion. 鈥淚n our [original] study we had thousands of samples,鈥� she points out.
The programme鈥檚 statistical adviser, Martin Bland of St George鈥檚 Hospital Medical School in London, declined to comment on the issue of sample size. He did tell New 杏吧原创, however, that 鈥渋t is obviously true that because one system fails to detect 鈥榤emory鈥� in one experiment we cannot infer that there is no 鈥榤emory鈥�.鈥�
Nathan Williams, the programme鈥檚 producer, stresses that each of the 40 samples was tested on several different sets of cells, boosting the statistical power of the study. 鈥淲e weren鈥檛 attempting to replicate the much larger studies, as there are problems with the counting methods used,鈥� he says.