There are two reliable ways of telling if you have won an argument. The first is if your disputants switch from discussion of the facts to accusations about motives; the second, more obviously, is if they descend to mere abuse.

Alan Dangour, a nutritionist at the London School of Hygiene and Tropical Medicine, should therefore feel he has had an encouragingly uncomfortable week. He is the author of a peer-reviewed meta-study in the American Journal of Clinical Nutrition that concluded, from 50 years of scientific evidence, that so-called “organic” food was no healthier than conventionally farmed products. By the end of last week Dangour felt as if he had been covered with the brown stuff the organic lobby holds most sacred. He revealed that he had received “hate mail” and was “taken aback” by the “abusive” language used.

Ben Goldacre, an NHS doctor and author of the acclaimed book Bad Science, has had a similar week. In his newspaper column he had taken apart the Soil Association’s criticisms of Dangour’s paper – which was funded by Britain’s Food Standards Agency – notably its claim that the health benefits of organic food relating to the absence of pesticides “could not be measured by the evidence identified in the FSA paper”.

As Goldacre pointed out to the Soil Association: “Either you are proposing that there are health benefits which cannot ever be measured. In this case you have faith, which is not a matter of evidence. Or you are proposing that there are health benefits which could be measured, but have not been yet. In which case, again, you have faith rather than evidence.” Cue an avalanche of organic ordure on the “comments” section at the foot of the online edition of Goldacre’s column.

When I called him, he remarked: “In my experience the [comments of the] organic food, antivaccine and homeopathy movements are unusually hateful and generally revolve around bizarre allegations that you covertly represent some financial or corporate interest. I do not; but I do think it reveals something about their own motives that they can only conceive of a person holding a position as a result of financial self-interest.”

His linking of the organic movement with homeopathy is telling. They are cults masquerading as science, rather like the creationists of America’s Bible Belt – but at least the latter have the self-awareness to acknowledge their opinions are based on faith. The organic movement, philosophically, is based on an inchoate faith in nature, seeing any human interference with nature as in some way bad and destructive of the “roots” of creation.

As Luc Ferry, the French philosopher, wrote in The New Ecological Order: “The hatred of the artifice connected with our civilisation... is also a hatred of humans as such. For man is the antinatural being par excellence... This is how he escapes natural cycles, how he attains the realm of culture, and the sphere of morality, which presupposes living in accordance with laws and not just with nature.” Guided by Ferry’s insight that this philosophy is based on “hatred” of humanity – and I accept this is dangerously close to an attack on motives – we should hardly be surprised by the nature of the e-mails directed at Dangour and Goldacre.

Nor, indeed, should anyone have been in the least surprised by Dangour’s results. The more rational among the organic movement long ago stopped claiming as scientific fact that their products are better for humans. The Canadian Organic Growers, reacting less hysterically than the Soil Association, responded to Dangour’s survey by saying that it “didn’t make health claims based on the nutrition of organic food”. This is the scientifically responsible attitude; but it is also a deadly blow to the marketing of organic foods, which depends on yummy mummies continuing to believe that if Cecilia and Frederick are fed only organic foods, then the little darlings will grow up healthier and stronger. It is in this sense that the organic business – ordinary food at extraordinary prices – is nothing more than a tax on gullibility.

Such gullibility can have dangerous effects on your health, as well as your bank balance. A few years ago my wife decided we should have an entirely organic vegetable garden. To this end she refused all man-made fertilisers and ordered a truckload of pigeon droppings. What could be more natural? Neither was there anything unnatural in the germs I inhaled through the spores of our organic manure, thereby contracting psittacosis. This developed into “atypical” pneumonia, which was of course resistant to all standard antibiotics. Had a hospital doctor not guessed the cause and put me on a drip with the appropriate drugs – ooh, chemicals! – I could have become a fatal casualty of the organic movement. Obviously my wife might have ordered cow manure rather than pigeon poo; then I could have been felled by E coli instead.

Think about it from the other end: if chemicals and pesticides in foods are as dangerous for humans as the Soil Association claims, we should expect conventional farmers, who handle the stuff in industrial quantities, to be dropping dead before the rest of us with all sorts of chemical-induced cancers.

The most exhaustive analysis of this matter was published in 2004, a peer-reviewed paper by Professor Anthony Trewavas of Edinburgh University, entitled “A critical assessment of organic farming-and-food assertions with particular respect to the UK and the potential environmental benefits of no-till agriculture”. (Trewavas is an advocate of no-till farming, which avoids damage to the soil caused by ploughing; “organic” farmers must plough to destroy all the weeds which would otherwise have been killed by pesticides.) His paper revealed that “of 12 separate investigations on farmers involving in total about 300,000 people, 11 found that farmers had overall cancer rates very substantially lower than the general public”.

Trewavas concludes that “the reasons why farming is so healthy are not known, but these data indicate not only a null result for the hypothesis relating pesticide exposure to cancer, but a consistent result for the alternative, that pesticide exposure may protect against cancer”. I realise that publicising Professor Trewavas’s paper might itself cause medical problems, as Soil Association executives choke with rage, but I think this a risk offset by the benefits to the public as a whole.

The provocative professor also points out that in the period since 1950 – as pesticides and industrial farming took an increasing role in food production – “stomach cancer rates have declined by 60% in western countries”. This is generally ascribed to the fact that fruit and vegetable consumption has doubled in that period – but why did this change in diet occur? Because modern agriculture, aided by air freight, has been able to get such products to consumers at ever-cheaper prices all year round.

This just demonstrates the common-sense point that diet, rather than whether food is produced “organically” or not, is the key to healthy eating. It is that which lies behind the Ratner moment of the chief executive of Whole Foods, who confessed last week that he had been selling “a bunch of junk”. What the organic chain store boss was trying to say, I think, is that a high-fat diet is as bad for you when the food has an “organic” sticker on it as when it doesn’t.

The general public, however, had already begun to call the organic bluff, perhaps one reason Whole Foods’ sales have suffered over three consecutive quarters in the United States and Prince Charles’s Duchy Originals has seen its profits slump. That noise – half-fart, half-howl – you heard last week was the organic balloon bursting.

dominic.lawson@sunday-times.co.uk

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