Higher antioxidant, lower cadmium, and lower pesticide residues in organic crops [pdf]

>"Abstract

>"Demand for organic foods is partially driven by consumers’ perceptions that they are more nutritious. However, scientific opinion is divided on whether there are significant nutritional differences between organic and non-organic foods, and two recent reviews have concluded that there are no differences. In the present study, we carried out meta-analyses based on 343 peer-reviewed publications that indicate statistically significant and meaningful differences in composition between organic and non-organic crops/crop-based foods. Most importantly, the concentrations of a range of antioxidants such as polyphenolics were found to be substantially higher in organic crops/crop-based foods, with those of phenolic acids, flavanones, stilbenes, flavones, flavonols and anthocyanins being an estimated 19 (95 % CI 5, 33) %, 69 (95 % CI 13, 125) %, 28 (95 % CI 12, 44) %, 26 (95 % CI 3, 48) %, 50 (95 % CI 28, 72) % and 51 (95 % CI 17, 86) % higher, respectively.

>"Many of these compounds have previously been linked to a reduced risk of chronic diseases, including CVD and neurodegenerative diseases and certain cancers, in dietary intervention and epidemiological studies. Additionally, the frequency of occurrence of pesticide residues was found to be four times higher in conventional crops, which also contained significantly higher concentrations of the toxic metal Cd. Significant differences were also detected for some other (e.g. minerals and vitamins) compounds. There is evidence that higher antioxidant concentrations and lower Cd concentrations are linked to specific agronomic practices (e.g. non-use of mineral N and P fertilisers, respectively) prescribed in organic farming systems. In conclusion, organic crops, on average, have higher concentrations of antioxidants, lower concentrations of Cd and a lower incidence of pesticide residues than the non-organic comparators across regions and production seasons." //

This is not really true. Here's the National Organic Program: http://www.ams.usda.gov/AMSv1.0/nop. Anything sold as organic in the US has to abide by these guidelines. Here's the equivalent EU program http://en.wikipedia.org/wiki/EU-Eco-regulation. There are some small differences in requirements between the two in terms of prohibited inputs, but for the most part they are pretty similar. Other countries tend to follow one or the other programs as the US and Europe is where the organic consumers are. Obviously, determining where to draw the line between synthetic and natural is a judgement call, which some may disagree upon. But in a lot of cases it's pretty clear, and the authorities make distinctions accordingly. Another big question determining an input's permissibility: how does this input affect the biodiversity of the system?

You're right about "biodynamic" being ridiculous. All biodynamic farming, however, adheres to organic input regulations.

If you had some critique of the actual National Organic Program, that would be a more interesting avenue of inquiry.

On a general note, how do meta analyses handle publication biases? For example, this study used 343 studies to derive their conclusions. But what if there were 5000 studies which showed that organic and non-organic food have no differences, but were not published or peer reviewed because they were deemed "not interesting"?

Again quite a poor press release for a university.

* Antioxidants have lost a lot in recent studies in terms of supposed health benefits. Mentioning antioxidants without reference to today's antioxidants and health research is implying a not-proven health benefit of organic food for antioxidants, while the health benefit can only soundly be expressed for the lower levels of pollutants.

* There is no link to the paper or a preprint of the article.

Apart from this, it is great to know that organic food is less polluted than conventional food (and it would be great if we got those numbers down for conventional food as well).