The research will be unveiled in the UK on Saturday.
Researchers say there is now firm evidence that organically-grown produce is healthier to eat than conventional crops. The Soil Association, the group which campaigns for organic
farming, has told BBC Radio 4's Costing the Earth programme that organic
crops contain more nutrients.
Conventional farming: "Devitalising our
Director Patrick Holden said research has shown that
they contain more secondary metabolites than conventionally-grown plants. Secondary metabolites are substances which form part of plants'
immune systems, and which also help to fight cancer in humans.
Holden said organic crops also have a measurably higher level of vitamins,
and that this can benefit people who eat them.
By contrast, he
said, "intensive farming is devitalising our food". Holden said
the research, from Denmark and Germany, would be presented in the UK at
the association's conference on organic food on 8 January.
The researchers' findings will
strengthen the organic lobby, which has been accused of making exaggerated
and even unwarranted claims. The programme spoke to scientists who
said they knew of no evidence of any nutritional benefit from eating
Others claimed it could be positively dangerous,
especially when it was fertilised with sewage containing potentially
harmful organisms. Some maintained that many of the natural
pesticides produced by plants were potentially more of a risk than the
synthetic ones used in conventional agriculture.
And with organic
food costing appreciably more than ordinary products, one US cancer
specialist said organic farming was a "dangerous delusion". Poor
people would find it hard to afford the fruit and vegetables they needed
to reduce their cancer risk, he argued.
But the World Health
Organisation has estimated that between 3.5 and 5m people globally suffer
acute pesticide poisoning every year. Organic food, the programme
concludes, has individual advantages and disadvantages but overall it is
almost certainly beneficial on the broader scale.