I assume that everyone who is interested knows by now that the headlines claiming that a Food Standards Agency study showed that “organic food was not healthier” were grossly inaccurate. I want to know why journalists did not even read the first paragraph of the report itself, let alone any real analysis of the report itself, before reproducing the Food Standard Agency’s spin.
The report actually talks about nutrients, not health. The very first paragraph is very revealing about what is covered:
This review does not address contaminant content (such as herbicide, pesticide and fungicide residues) of organically and conventionally produced foodstuffs or the environmental impacts of organic and conventional agricultural practice.
So, the most important reason for preferring organic food is ignored. Herbicides, pesticides and fungicides are toxic: they would not work if they were not, at least, toxic to plants, pests and fungi! Large doses are toxic (ingesting these is a common way of committing suicide in some places), and I would very much like to know of any conclusive studies of the long term effects of continually eating small amounts with each mean.
Why did journalists fail to mention this for the first day or two? Did they no even read the executive summary (the easy bit at the top for people who are unable to understand the rest)?
Even regarding the nutritional content, it is obvious that there are not going to be huge differences in the content of the main nutrient groups in organic food and chemically grown food. However looking at the details, there are lots of differences that could be significant, for example the level of both phenolic compounds and flavinoids is higher in organic food,and, to quote from the report itself:
Numerous health benefits have been ascribed to the actions of phytochemicals such as phenolic compounds and flavonoids, many of which related to their antioxidant activity. The recent World Cancer Research Fund report suggests that quercetin (a flavonol) may prevent lung cancer (although the strength of evidence for this relationship was graded as “Limited – suggestive”4) (17). There is also some evidence from cohort studies (although not from randomised controlled trials), that high flavonoid intake is associated with lower rates of coronary heart disease mortality.
There are plenty of other examples. These are a bit more difficult to find, as they require reading the report, but it took me about ten minutes. I assume the failure of various journalists to find this reflects either a the extreme time pressures they work under — the media like quality, as long as it is cheap!
The other thing that is striking about the conclusions is that in many cases there is not enough evidence to draw a conclusion. It is basic to statistics that the larger the sample size the more meaningful the conclusions. For example, four of the studies of the effect on people used fewer than 20 participants, and most were conducted over short periods of time, so long term effects are ignored altogether. The fact that it is a study of studies also has other effects:
Statistical analysis was not attempted due to marked heterogeneity of study designs, exposures and outcome measures among the included studies.
Another flaw is that the studies did not use a consistent definition of organic. This varies from country to country (the US, for example, has a long list of ingredients that can be used in food labeled organic, that do not need to be produced organically) and from certifying authority to certifying authority. A far better approach would be to use only food produced to a strict definition of organic.
The most important conclusion of the study, is that nothing has really been proved. Neither then Food Standards Agency, or journalists, have paid much attention to this
A surprising and important finding of this review is the extremely limited nature of the evidence base on this subject, both in terms of the number of studies and the quality of studies found. It is essential that future research (both human and in vitro studies) is better designed and, at the very least, meets the minimum quality criteria applied in this review, including an accurate description of the organic certification process. It is recommend that in future, high quality randomised controlled trials should be conducted which have samples of sufficient size to reliably detect the presence of effects, longer and more realistic dietary exposures, and more accurate and objective approaches to measuring dietary intake and health outcomes.
There is little evidence that organic food is more nutritious so far, because no one has really looked, and if we assume that constantly eating small doses of known toxins is entirely harmless.