Edzard Ernst: The “natural” equals “safe” fallacy

Things that are natural must be safe—this fallacy is deeply ingrained in our minds; it almost seems that, as human beings, we are hard-wired to believe this myth. An entire industry has developed around this claim: from toothpaste to wine, from dog-food to hand-cream, products are deemed to be better if they carry the label “natural.” One sector which clearly thrives on this fallacy is alternative medicine (AM).

Much of the popularity of AM can be explained through our attraction to all things natural; according to its proponents, AM is natural; and, by definition, this means that it is devoid of risks—not like those nasty, synthetic, chemical prescription drugs, which are a major cause of mortality! This false logic convinces not just patients and consumers, it also seems to have bowled over large sections of the popular press and many politicians. Despite its popularity, the notion is obviously wrong and seriously misleading.

The first thing which any critical thinker must notice is the disarmingly simple fact that by no means all types of AM are natural. What, for instance, would be natural about an acupuncturist sticking needles into patients, a chiropractor forcing vertebral joints beyond the physiological range of motion, a homeopath endlessly diluting his remedies, or a colonic irrigationist pushing a tube “where the sun don’t shine.” The closer we look, the more we realise that, in AM, natural is little more than a false label which might be good for PR, but which frequently does not coincide with reality.

The next thing we cannot fail to observe is the indisputable fact that an entirely risk-free therapy does not exist—and this, of course, applies also to those forms of AM which have the reputation of being entirely safe. Homeopathic remedies, for instance, are usually as devoid of active molecules as they are of direct adverse effects. But this does not mean that homeopathy cannot do any harm! In fact, any ineffective treatment that is used for serious conditions will inevitably cause substantial harm, if it replaces effective therapies.

Other forms of AM have been associated with considerable direct risks. Chiropractic manipulations, for instance, have been linked to numerous serious complications such as stroke and death.

Similarly, herbal remedies can cause adverse effects through the toxicity of their ingredients or through interactions with synthetic drugs. Colonic irrigation has led to electrolyte-depletion and gut perforation. Aromatherapy may cause allergic reactions, etc, etc.

But, on the whole, AM is relatively safe, ie it causes less problems than conventional treatments, enthusiasts would insist. This argument may well be true but, if employed to promote AM, it is nevertheless misleading. Firstly, we need to point out that, in AM, the post-marketing surveillance systems of conventional medicine do not exist. It is therefore conceivable, perhaps even likely that adverse-effects of AM are simply not being picked up. In this case, our impression of AM’s relative safety would not be entirely correct. Secondly, we should remind ourselves that the value of a treatment is not determined just by its safety; there are many safe yet useless interventions as well as harmful yet useful therapies. The worth of any given treatment is determined by the question whether it generates more good than harm. If a treatment is ineffective, even the smallest risk might tilt the risk-benefit balance into the negative. If another treatment is burdened with serious adverse-effects but its actions could save a life, it might still be highly useful.

The conclusion from all this could not be simpler: the assumption that “natural” equals “safe” is wrong. In the realm of AM, it is widely used for promotional purposes—and that is wrong too, so much so that it can endanger the health of those who fall for this fallacy.

Edzard Ernst is emeritus professor of complementary medicine at the Peninsula Medical School, Exeter.