A blog about science, medicine, media and the ramblings of Irish hack....

Wednesday, May 25, 2011

Oh the bitter Herbs......

 My 2c on the EU directive for herbal medicine. Thanks to Prof. William Reville of the Irish Times / UCC for casting his expert eye over this...

The European Directive on Traditional Herbal Medicinal Products has of late provoked the ire of advocates and practitioners of complementary and alternative medicine (CAM). From the impassioned furore, one might be forgiven for thinking that the directive is a sudden new and draconian imposition. But the directive has in fact been in force for 7 years, brought in after a number of deaths and accidents involving herbal medications. It is hardly draconian either - instead of demanding proof of efficacy through independent clinical trials as with any other medical product, the legislation simply asks those wishing to supply a herbal product to provide anecdotal documentation it doesn't harm and has a track record of at least 15 years usage. The deadline for registration of existing products has just past, and this is being presented as an attack on herbal practitioners. A vocal number of herbal advocates have claimed this legislation is a ploy by big pharmacy to drive them out of business but this entirely predictable claim is a straw man argument - the issue here is regulation, pure and simple.

Despite the claims of some practitioners, there does not seem to be any grounds for thinking the public are against regulation. A study conducted in April by the Irish Medicines Board found that 77% of consumers think that herbal health products should be regulated, and that they would inform their physician if they were taking any. A wise move - several herbal products on the market can interact negatively with conventional treatments and even exacerbate conditions. For example, the widely used St John's wort interferes with oral contraceptives and HIV medication, reducing their effectiveness. This is not to say that there is anything wrong with the St. John's wort; clinical trials indicate that it can be effective in the treatment of depressive disorders, but like any medication it has contraindications that need to be careful studied and regulated. Anything that has a biological effect, from the mundane to the exotic, is likely to have some side effects. Herbs and traditional medicines are not exempt from this credo.

An oft repeated claim is that because herbs are 'natural' they are 'safer' than conventional medication. Even ignoring the somewhat subjective interpretation of the word natural, this is an utter fallacy - natural is in no way synonymous with benign or even beneficial.  Aristolochia, often used in traditional Chinese medicine, can destroy kidneys and can be carcinogenic. Kava, used for some herbal stress medicines, can dangerously alter liver function. It was banned in the UK after killing three and necessitating a further 6 liver transplants.  Foxglove, Wolfsbane, Hemlock, and Arsenic are just some examples of naturally occurring fatal poisons. There are countless other examples which indicate the folly of conflating 'natural' with 'safe'. What is important to note is that prepared correctly, they all have some medicinal value - but the therapeutic index (the margin of error between a therapeutic and lethal dose) is often very narrow. A case in point is foxglove - it contains digoxin, which forms the active ingredient for the treatment of certain heart problems. The range between the beneficial and the detrimental is quite small, and lots of peer reviewed research went into not only finding this range but examining the mechanism of action to better understand what was happening. Not only did the pioneering researchers do that, but they found that starting with standardized plant preparations gave dangerously inconsistent amounts of digoxin. They extracted this active ingredient so dose could be exactly weighed and monitored resulting in a usable medicine. Herbalists often object to this practice, claiming without any evidence that isolated extracts are somehow inferior to the whole plant. 

But the problems of lack of regulation aren't solely confined to medical risk. They also leave the door wide open for exploitation and fraud. In May 2010 the US Government accountability office (GAO) released a report entitled "Herbal Dietary Supplements: Examples of Deceptive or Questionable Marketing Practices and Potentially Dangerous Advice". Posing as elderly customers, GAO staff contacted sellers with a viewpoint to determining whether questionable selling practices were a wide scale problem. What they found was shocking in both nature and extent - several practitioners claimed to be able to cure ailments such as cancer, heart disease and Alzheimer's. As if this conduct wasn't bad enough, several herbalists further gave staggeringly bad medical advice, such as discontinuing medical prescriptions in favour of untested products. The GAO also sent 40 samples of products to their labs for testing. 37 of these had higher than expected trace levels of lead, cadmium and arsenic. The complementary medicine market is a big one ; NCCAM estimates that Americans spend €33.9 billion a year on it. The figure in Europe is likely to be similar if not higher. In a market with high profits, no liabilities and no regulations it is easy to see why practitioners of CAM oppose moves to change this. This isn't to say that all these employees are deliberately engaging in deception - their beliefs may be sincere but that doesn't make them correct.

This raises an interesting point. There are hundreds of herbal medicines on the market and unravelling those with some degree of efficacy from the many that are ineffective is difficult. The scientific gold standard for effectiveness is the double blind trial, where some patients are given a placebo and some  the ingredient to be tested. Neither the subjects nor the medical testers are aware which group has which. This means an unbiased analysis can be performed. So far, only a small percentage of herbal remedies have been tested, and in this small group an even smaller fraction have been shown to have any actual benefit. The remainder either have no medical benefit or are actively damaging. Herb 'cocktails' offered by some herbalists are even more of a risk to health through interactions. And worse, there is no evidence they work but plenty to suggest they can expose users to potentially toxic doses and negative interactions.

In the realm of science and medicine, anecdotal evidence is no evidence at all, and for good reason - oftentimes reality is at odds with the common perception and only fair objective analysis can give any real answers.Therein lies the rub - either a given product has medicinal effect or it does not. If there is a medical effect, then of course it should be regulated to avoid side effects. If there is no medical effect, then claiming the product is a medicine or remedy is disingenuous and the product useless. Herbal advocates cannot have it both ways - either their product is biologically active or not. And if it is biologically active, then it should be regulated as any other medicine. Herbal medicine has much to contribute to health science, but it must do so in the frame work of peer review and careful analysis to ascertain not only what works and what doesn't but what harms and what heals. This must be based on evidence, not appeal to antiquity. The new legislation should in theory address this, but even a cursory glance reveals the loophole in the logic - the legislation gives undue deference to tradition by accepting anecdote rather than examining the truth.

Perhaps the real problem with the herbal medicines directive is not that it is too harsh, but far too lenient.

1 comment:

  1. This article reminds me of the arguement I used when people would try the "it's natural" route with various drugs in my teen years.

    "Tigers are natural too".


What do you think? Have your say!

Related Posts Plugin for WordPress, Blogger...