Most
shoppers know the feeling. You stand in front of piles of organic
produce and wonder what those premium prices are buying you over and
above what you get from budget foods. A new study has concluded that, on nutrition grounds, the answer is nothing. But we are missing the point when we worry about the nutritional pros and cons of organic food?
The problem is that head-to-head comparisons between
organic and conventional crops, which the media loves to focus on,
leave no room for other contenders.
There
are many ways of farming and some offer advantages over others. By
obsessing over just one aspect of food production – whether it is
organic or not – we lose sight of other important issues, like the need
to reduce greenhouse gas emissions from farms, and the vital question of increasing food supply and security.
'Wrong question'
"It's not about whether organic food is good or a sham," says Jules Pretty,
an agricultural scientist at the University of Essex in Colchester, UK.
"That's the wrong question. We should be asking how we can make all of
agriculture more sustainable."
Understanding
nutrition is, of course, still vital when it comes to choosing food. A
team from the London School of Hygiene & Tropical Medicine examined
162 papers that compared organic and conventionally produced food: they
concluded that there was no evidence to back up claims that organic
food contains more of the nutrients that matter to human health.
So
it seems consumers should not buy organic food purely on health
grounds. However, nutrition is only one of the aspects of food that
shoppers care about, and the situation becomes more complex when these
other issues are factored in.
Pros and cons
Take energy use. Some organic farming systems have been shown to be more energy efficient
than conventional farming methods, partly because they do not use
synthetic fertilisers, which are energy intensive to produce and
release large amounts of carbon dioxide into the atmosphere.
Yet organic farms themselves could improve the way they work. Pretty says that some use propane burners, which produce CO2,
to keep weeds down. But there is limited pressure on organic farmers to
cut emissions because they don't have to do so in order to qualify for
organic status.
Soil
erosion is another problem area. Many organic farms emphasise crop
rotation, in part to ensure that fields are not left uncovered and
vulnerable to erosion. But some organic farmers actually cause erosion
by tilling the soil frequently, again to keep down weeds. Conventional
farmers often use chemicals to tackle plant pests, but these come with problems of their own.
Defining goals
"Organic agriculture is not without environmental consequences," says Laurie Drinkwater, an expert in sustainable agriculture at Cornell University in Ithaca, New York.
Rather
than compare organic and conventional systems using simplistic
comparisons, Drinkwater and Pretty say we should start by identifying
the things we want from farms.
Food
production is the obvious one, but farmers can also help boost
biodiversity, keep rivers free of certain kinds of pollution, and fight
climate change. There is also the question of animal welfare. Farming systems should then be judged on how far they go towards meeting all those goals.
The
result would probably be a system that borrows techniques from many
existing methods. That would be good news for farmers and the rest of
society, even if it might not produce so many snappy headlines.
By Jim Giles From
NewScientist