Oct 08 2012
I don’t have any a-priori or ideological issue with any of the specific practices that fall under the “organic” rubric. I do have a problem with the fact that there is an organic rubric. In fact I think the USDA made a mistake in giving into pressure and creating their organic certification. At the time they tried to make it clear that “certified organic” said absolutely nothing about the product itself, only that certain rules and restrictions were followed in production. It was not an endorsement of organic farming, just a way to regulate the use of the term in labeling food. Unfortunately, it further solidified the organic false dichotomy.
The published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods. Consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.
Some of the reaction to the Stanford study, and my discussion of it, illustrates the problem with the false dichotomy – it encourages muddy thinking. There is a range of practices that are allowed and not allowed in organic farming to meet USDA certification. Excluded practices include genetically modified (GM) ingredients, ionizing radiation, and use of sewer sludge. There is also a long list of allowed and excluded substances (such as organic vs non-organic pesticides).
This is a very diverse list of substances and practices. What does the use of ionizing radiation have to do with the relative advantages or disadvantages of plant-derived vs artificial pesticides? There is only one common theme that runs through all of these practices and that is, in my opinion, the naturalistic fallacy.
To be clear – I am not saying that there are no reasonable justifications, both on the evidence and philosophy, for any particular practice that is considered organic. I am just saying that lumping a diverse group of practices together under one certified marketing label discourages a dispassionate assessment of the risks and benefits of each individual practice. They are now a package deal.
Let’s get back to the Stanford study and specifically a New York Times opinion piece about the study and the media reaction to it. Mark Bittman argues:
If I may play with metaphor for a moment, the study was like declaring guns no more dangerous than baseball bats when it comes to blunt-object head injuries. It was the equivalent of comparing milk and Elmer’s glue on the basis of whiteness. It did, in short, miss the point.
How can something that reduces your exposure to pesticides and antibiotic-resistant bacteria not be “more nutritious” than food that doesn’t?
Because the study narrowly defines “nutritious” as containing more vitamins.
I think it is Bittman who misses the point. He is essentially criticizing the study for using a “narrow” definition of “nutritious.” That is one of the most scientifically naive statements I have read in a while. Scientists should use as narrow a definition of any term as possible – and by “narrow” I mean specific and precise, preferably with an operational definition detailed in the study.
Bittman accuses the authors of unfairly attacking all of organic farming by focusing on one narrow aspect of it – the nutrient content of organic produce. He compares this to the whiteness of glue vs milk, which is a false analogy. A proper scientific study, however, should separate and clearly define specific variables, not lump them together with a vague colloquial use of terms, as Bittman recommends.
I believe this is the kind of muddy thinking encouraged by the use of the term “organic.” The authors were addressing a very specific question – what does the current evidence say about the nutrient content of organic vs conventional produce? They added two separate questions about pesticide residue and antibiotic resistant bacteria – two factors that have absolutely nothing to do with the nutrient content of food.
I think Bittman’s attitude, and obvious anger at the study, reflects a general trait of human psychology – the need for simplicity. The world is a complex place, and we partly cope with that complexity by simplifying it in our minds. We use categories, pigeon holes, bottom lines, and executive summaries to break down the complex work into bite-sized chunks that we can handle. There is nothing wrong with this – I do this all the time, often consciously. I am aware of the fact that I cannot remember all the nitty gritty details about every subject, and so I often with boil a topic down to its important essence and try to remember that. However, I also couple with the bottom-line summary, knowledge of the fact that the topic is much more complex, and perhaps even some idea of the nature of that complexity, so I will remember to look into it further if those details become important. This approach also encourages humility toward topics of which I can remember only a simplified overview, and deference to experts who live in the nitty gritty details.
Often, however, an oversimplified approach, without recognition of the true complexity, is very counterproductive. Scientists cannot take this approach, they must delve as deeply as possible into the complexity.
When thinking about farming practices we should look at each practice on its own merits, with respect to every important outcome, such as the cost of production, land requirements, productivity, multiple environmental effects, sustainability, health effects on workers, nutrient quality and content of the food, and other specific health characteristics of the food. These should be considered separately, for each practice, based on the best evidence available. It is scientifically absurd to lump a long list of diverse practices together with a long list of outcomes and try to come up with a overall assessment – is organic farming better than conventional farming? The question is meaningless and deceptive, but that appears to the question that Bittman wants to ask, and he criticizes the authors of this review for not addressing it.
To some extent, however, we are stuck (at least for now) with the false dichotomy, since it has been adopted into regulations with the USDA certification. At least there is an operational definition as to what is “organic” and we can ask specific questions about the net effect of that. There is still the problem that “not organic” can run the full spectrum from almost but not quite organic to breaking every single criterion of the organic label. This is what we have for real world studies, however – looking at what farmers and agricultural companies are currently doing. It would be better to isolate each variable from the rest, and some studies do that.
What the Stanford study showed was three things – that organic certified produce are not significantly different in terms of nutrient content from conventional produce, that there is greater pesticide residue, and there is a greater risk of antibiotic-resistant bacterial contamination on conventional food. Bittman also brings up the fact that other researchers contest the first finding, but I think Bittman is cherry picking here. The systematic reviews that I can find largely agree that:
“On the basis of a systematic review of studies of satisfactory quality, there is no evidence of a difference in nutrient quality between organically and conventionally produced foodstuffs.”
Some studies do show a small difference, but it is possible that the small increase in nutrient density is caused mostly or entirely by the smaller size of organic produce.
With regard to the pesticide residue issue, while there is no question at this point that conventional produce has greater residue of conventional pesticides, this comparison may actually suffer from the kind of problem that Bittman falsely accused the Stanford study of – making a biased comparison. Most studies look for synthetic pesticides – so of course there are more synthetic pesticides on food grown with synthetic pesticides. Generally, however, they don’t look for the “biological” pesticides allowed for on organic food, because it is assumed they are safe (based solely on the naturalistic fallacy, as far as I can tell).
Further, there is no evidence that the levels of pesticides on conventional produce represent any health risk. They are well below safety limits. It should not be assumed, therefore, that the even lower level of synthetic pesticides on organic produce translate into a health benefit. The same is true of contamination with antibiotic resistant bacteria – there is no evidence this represents a health risk for the person who consumes the food. We have to distinguish this from the safety of farm workers and the overall impact this has on the existence of antibiotic resistant bacteria in the world. There is a good case to be made for farming practices that do not rely on dosing animals with antibiotics.
Good science requires precision of definition and obsessive isolation of specific variables and specific outcomes. In order to optimize our food production industry with respect to as many outcomes as possible, we need to be able to ask and answer many specific questions. I want to know the effect on specific nutrient content of a specific kind of ionizing radiation on romaine lettuce. We can add this narrow bit of information to evidence for cost, other effects on nutrient quality, shelf life, adverse effects from bacterial contamination, and the net impact of the process on workers and the environment. If there is a way to further look at the net health impact of the practice, that would be useful information. Then we can look at all these individual bits of data and make an informed judgment about the costs, risks, and benefit of this specific practice, to individual consumers and to society.
What we don’t want to do is combine many practices and many outcomes together in a muddy way and then defend one ideological position or the other at all costs. It is probably too late, but in an ideal world I think we should abolish the concept of “organic farming.” Rather we should strive for sustainable and environmentally friendly farming practices that maximize production, minimize land use, minimize negative environmental impacts, and produce nutritious and safe products that people can afford.
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