Researchers concluded that the additional “stress” of an organic farming operation makes the plants boost their production of phytochemicals. In other words, the plants must cope with greater challenges from natural insect predators and disease so they respond with a higher output of defensive compounds, which can benefit people, too.
From: Organic Consumers Association
Why organic produce may be worth the money
By Paul Taylor
The Globe and Mail
Published Thursday, Feb. 21, 2013
For the study, the researchers selected tomatoes from an organic farm and a conventional operation located 1.5 kilometres apart in northeastern Brazil. So the plants were raised in roughly the same weather and soil conditions.
The organic farm used animal manure for fertilizer and a naturally based fungicide, while the conventional farm relied on a chemical fertilizer and pesticides.
From outward appearances the organic tomatoes did not do so well – they were roughly 40 per cent smaller than those grown conventionally. But a detailed analysis, published in the online journal Plos One, revealed the organic variety contained elevated concentrations of vitamin C and other phenolic compounds.
“The contents in phenolic compounds and in vitamin C were 139 per cent and 55 per cent higher, respectively. That is quite a lot,” one of the researchers, Laurent Urban of the University of Avignon in France, said in an e-mail interview.
The researchers, led by Raquel Miranda of the Federal University of Ceara in Brazil, concluded that the additional “stress” of an organic farming operation makes the plants boost their production of phytochemicals.
In other words, the plants must cope with greater challenges from natural insect predators and disease so they respond with a higher output of defensive compounds, which can benefit people, too.
For instance, vitamin C and phenolic compounds act as antioxidants, neutralizing free radicals that can cause cell damage. Previous studies have shown that a plant-rich diet is associated with a lower risk of cancer, heart disease and other illnesses.
The researchers noted that the agricultural sector has been primarily focused on increasing crop yields.
“This might be all right for staple food, but as far as fruits and vegetables are concerned, it may be argued that gustative and micro-nutrient quality matter more than energy supply,” they write in their study.
“Our observations suggest that, at least for fruits and vegetable production, growers should not systematically try to reduce stress to maximize yield and fruit size, but should accept a certain level of stress as that imposed by organic farming with the objective of improving certain aspects of product quality.”
In the meantime, Urban pointed out that many people don’t eat enough fruits and vegetables to reap their potential benefits. Those grown organically at least contain more nutrients per mouthful. What’s more, this type of agriculture isn’t associated with the same level of pesticide residues found in some conventionally grown crops, he added.