Casting a cold eye on organics

By Con O'Rourke*

Organic foods are treated in the 'lifestyle' features of the media with a respect bordering on reverence. Interest in such foods is driven by concerns about food safety and the environment, but perhaps also as a fashion statement by the chattering classes. Maybe it's time to 'cast a cold (scientific) eye' over the whole organic sector to see how its various claims and assumptions stand up.

What is 'organic'?

Organic foods are those grown without the aid of manufactured fertilizers and pesticides. Unfortunately, the wholesome image of 'organic' has also been adopted by advertisers to sell many other products such as cosmetics and 'organic pure water' (go figure!). 'Organic' is becoming a debased clichÅ, rather like 'executive', 'designer' and 'de-tox' before it.

The nutrition of green (photosynthetic) plants is an entirely inorganic process. Plants use sunlight to synthesise living tissue from the simple raw materials carbon dioxide, water and a range of minerals. The term 'organically-grown' is a misnomer, since the plant roots can absorb soil nutrients only in their simplest (inorganic) form, e.g. as ions of the major nutrients nitrogen, phosphorus and potassium (NPK). 'Organic' should be replaced with a less ambiguous term, possibly adapted from the German or French equivalents of 'biologisch'/'Îkologisch' or 'bio'.

Since crops can absorb the identical NPK ions from the soil solution, from the breakdown of organic matter (both naturally-occurring and applied) or from commercial fertilizers, nutrient analyses cannot prove that a particular food has been 'organically-grown'. Thus the approval and inspection procedures for the provenance of organic produce are based more on trust than on science.

Nutrition /taste

Organic foods are claimed to be more nutritious and to taste better, with Darina Allen of Ballymaloe going so far as to declare that they are essential for health. However, such claims would have to satisfy all of the following criteria: 1) Randomised, replicated field trials of the same variety, grown both organically and conventionally under otherwise identical conditions: 2) Laboratory analyses of the produce for all major nutrients (carbohydrates, fats, proteins, fibre, minerals, vitamins, etc.): 3) Double-blind taste-panel evaluation (i.e. where neither the tasters nor the presenters know the origin of particular samples): and 4) Statistical analysis of the results and publication in peer-reviewed scientific or medical journals. Few organic claims satisfy even one of the above criteria.

The Soil Association (U.K.) had claimed for over 50 years that organic produce was more nutritious and tasted better. However, when recently challenged by the UK Advertising Standards Authority they were unable to provide creditable supporting evidence and had to cease making such claims.

Pesticide residues

Analyses by the Department of Agriculture show that Irish staple foods (mainly dairy/meat products and vegetables) contain either no or negligible amounts of pesticides. The prescribed limits for pesticides (parts per million or per billion) are occasionally exceeded, mainly in imported tropical products, but such limits are set at about 1/100th or less of what might be considered harmful. Sir John Krebs (UK Food Standards Agency) has remarked that 'A single cup of coffee contains natural carcinogens equal to at least a year's worth of carcinogenic pesticides in the diet'.

The environment

Organic farming is promoted as being environmentally friendly. This is based mainly on using less (or no) pesticides and organic manures/composts instead of commercial fertilizers. In conventional farming, however, pesticides are increasingly restricted to more environmentally-friendly and biodegradable products. The rates and times of fertilizer application are also limited by the EU Nitrates Directive.

Dairying and beef dominate Irish farming. Both are mainly grass-based - a major marketing advantage for our 'green and clean' image. No pesticides are applied to Irish grassland, and strictly-supervised fertilizer inputs are confined mainly to nitrogen for spring growth and sufficient phosphorus and potassium to replace what is removed by the grass. This is as close as it gets to 'organic'.

Organic Island

The organic sector regularly calls for Ireland to become an 'organic island'. This might work if we had a completely self-contained agriculture, with no imports or exports, and complete recycling of all crop, animal and human wastes and remains. But we export more than 80% of our output, and with it some of the nitrogen, phosphorus and potassium used in its production. Although some nitrogenous losses can be replaced by growing N-fixing leguminous crops, we have scant native deposits of phosphorus and potassium. Without imported fertilizers, yields would gradually decline to 19th-century levels, with serious losses of exports and jobs. A foretaste of this scenario occurred in Ireland during World War II; in the absence of imported fertilizers, phosphorus deficiency became widespread in both crops and animals.

GMOs

Genetically-modified (GM) crops have been around since the 1970s and now total 100 million hectares annually worldwide (about 15 times the entire farmed area of Ireland). They have been consumed regularly by some hundreds of millions of people and have been found to be no less safe than conventional foods. Predictions of environmental and ecological catastrophe have failed to materialise. Consumer resistance to GM foods in Europe is sustained by the tabloid press ('Frankenstein foods'), environmentalists, organic growers and by the EU restricting GM food and animal-feed imports (usually on dubious health and environmental grounds).

BASF is planning field trials of GM blight-resistant potatoes in Ireland. At present, organic potato growers have a special dispensation to spray against blight. However, their rules restrict them to traditional (19th-century) copper-based sprays.

Copper is a persistent and poisonous heavy metal, with long-term environmental effects, and is soon to be banned by the EU. GM potatoes would require no spraying and will not 'contaminate' adjacent conventional (and particularly organic) crops since, as every gardener knows, potatoes are propagated asexually by vegetative tubers rather than by pollination. It is ironic that current organic rules ban a GM variety which has such obvious benefits for the sector.

World population

Organic yields are significantly lower than for conventional crops and they are currently incapable of feeding the world's six billion people. To do so would require about a doubling of the area under cultivation, with consequent destruction of natural habitats. An organic world could, however, be achieved by eliminating half the population - but which half, and who decides?

cost

Due to lower yields and higher labour inputs, organic foods cost up to 50% more. This may be of little concern to the virtuous suburban housewife on her weekly 50-km round-trip in an SUV to buy a few kilos of organic vegetables in a farmers' market. There is a certain paradox in that growth of the organic sector has coincided with increasingly strict regulations to ensure that our food is safe and that the environment is protected. Thus a consumer's decision to 'go organic' may be due more to a general lifestyle choice (and increased affluence) than to specific health or environmental threats.

* Dr Con O'Rourke is a plant scientist.