Tuesday, September 4, 2012

Organic versus conventional foods--no winner?

A strawberry. Can you tell
if it is organic or not?
[Photo credit:  Rasbak from nl.]
By Emily Willingham

A report on organic foods has just come out from a Stanford University team, and the headlines, such as this one from the New York Times, pretty much say what everyone's saying about it: Organic foods aren't any better for you, nutritionally, than conventional foods. 

According to the NYT report, the Stanford researchers spent four years looking over more than 200 studies, evaluating various aspects of research findings about organic versus conventionally farmed or ranched plants and meats. The kind of analysis they did is called a "meta-analysis" because it goes beyond--or "meta"--a single study and looks at a pile of existing data to analyze. 

The NYT piece and a lot of what I've been seeing on Twitter gives the impression that people buy organic foods because they think these foods are nutritionally superior to conventionally produced foods. In that context, according to the NYT piece, the researchers
concluded that fruits and vegetables labeled organic were, on average, no more nutritious than their conventional counterparts, which tend to be far less expensive. Nor were they any less likely to be contaminated by dangerous bacteria like E. coli.
The researchers also found no obvious health advantages to organic meats.
The problem? This is purely anecdotal (although at least one poll supports it), but the people I know who buy organic don't do it because they've got some idea that an organic strawberry's got more vitamin C than a non-organic one. They do it because of the rules governing the production of organic fruits and vegetables and organic meats. Their reasoning is that these processes will result in foods with less pesticide residue and less contamination with antibiotic-resistant bacteria. Guess what the Stanford team found? Again, from the NYT:
Conventional fruits and vegetables did have more pesticide residue, but the levels were almost always under the allowed safety limits, the scientists said
and
Organic produce, as expected, was much less likely to retain traces of pesticides....Organic chicken and pork were less likely to be contaminated by antibiotic-resistant bacteria.
That finding for pesticides alone is one reason many people I know who buy organic do so. 

One of the Stanford researchers acknowledged as much in the NYT piece:
Dr. Bravata agreed that people bought organic food for a variety of reasons - concerns about the effects of pesticides on young children, the environmental impact of large-scale conventional farming and the potential public health threat if antibiotic-resistant bacterial genes jumped to human pathogens. "Those are perfectly valid," she said.
Indeed, the piece does include an observation from an analyst with the Environmental Working Group noting that the "more nutritious" concept has "never been a major driver" in people's decision to buy--and pay more for--organic food. That said, organic producers do tend to emphasize the "nutritional superiority" of organically produced foods. Perhaps their advertising is poorly targeted.
Oddly enough, the researchers did find some potentially higher nutritional benefits of some organic foods, such as more "heart-healthy" omega 3 fatty acids in organic milk compared to conventionally produced milk.
What about you? Do you buy organic? If so, what are your reasons? 
-------------------------
For further reading, check out the online brouhaha that blew up last summer, ignited by this article from Christie Wilcox, writing at Scientific American blogs. 

These views are the opinion of the author and do not necessarily reflect or disagree with those of the DXS editorial team.

8 comments:

  1. When my daughter was weened and drinking only cow's milk, we did buy organic milk for her- since it was a major source of her nutrition at the time.

    Our decision on the milk was based on the nutritional profile (http://blogs.scientificamerican.com/observations/2011/01/17/organic-milk-delivers-more-consistent-nutrition-across-seasons/) and on the environmental impact of buying so much milk (I can't recall or find the reference- a SciAm blog post perhaps?- that suggested it was more environmentally friendly).

    Now that she eats a varied diet (or as varied as it can be with a picky toddler) we buy regular milk. In our area, we find that the selection of organic fruits and veggies is limited at regular food stores and prohibitively expensive at organic food stores. Thus, we generally buy conventionally farmed fruits and veggies.

    This decision was based on the aforementioned availability and fiscal concurs as well as previous studies that were inconclusive about the health benefits. This SciAm post was enlightening (http://blogs.scientificamerican.com/science-sushi/2011/07/18/mythbusting-101-organic-farming-conventional-agriculture/)

    As for meats, we buy those conventional as well- except for some of our beef. A family friend has a farm and raises grass-fed cows (not certified organic, but since we know and trust him, that's not a concern) and we buy a cow each year and split it with my parents. The meat from this cow is delicious! Other than the fact that we have to lay out several hundred dollars all at one, and invested in a chest freezer, this option in the long run is quite cost effective.

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    1. Hi, Courtney-- We linked to Christie's post at the end of the above post, and it is definitely worth reading. Also, if you scroll the the bottom of her post--where there are a LOT of comments--you'll find a link to her rebuttal to the rebuttals of her post. It was quite an online exchange and worth the long read if you have the time.

      Interesting about buying the whole cow. I'm just not sure where we'd put the freezer at this point.

      Thanks for commenting!

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  2. Yes, we do buy organic. There are a few reasons: the taste is far better in most cases; the environmental impact is one of sustainability (when done correctly, of course you can screw up land in many ways); most organic sources we use are regional rather than shipped internationally or across the country ("local" is a pretty loose term these days).

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    1. Thanks for commenting. Where we shop in our town, they have an entire section now devoted to the foods that are state grown and throughout all of the aisles, they have signs that indicate if a food is local or state sourced.

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  3. I buy some organic and some conventional produce. I always buy organic milk and yogurt but not so much with cheese. With dairy, I don't want to consume extra hormones. Deciding to buy organic has to do with price, availability, and science. I have never bought organic because I thought it to be more nutritious but because of pesticide residues. Thus, produce I can more easily clean or research has shown has less residue, I am more comfortable buying conventional. However, another reason I like organic is bigger picture. Many pesticides are applied way too liberally, and they contaminate the soil and water sources. Thus, I don't want to contribute to the destruction of the environment by supporting these practices. I also worry about the farm workers and their families. Workers are generally not protected from exposure, or not to the extent they really should be. Furthermore, the exposed farm workers will often unintentionally expose their families by not changing clothes after working near pesticides. (I would have to dig up the journal articles on this). Finally, I prefer organic dairy and meat (when I can get it) because of the treatment of animals. I don't know if there is actually a correlation between organic meat not coming from factory farms, but at least I know the animal is not being pumped full of unnecessary medication. Thus, there is a multitude of reasons why I like organic, but none of them have to do with nutrition.

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  4. Here's what I don't understand:

    1) "Conventional fruits and vegetables did have more pesticide residue, but the levels were almost always under the allowed safety limits"
    2) "That finding for pesticides alone is one reason many people I know who buy organic do so."

    These two contradictory statements show that consumers don't understand the science behind pesticide testing. How do we get the word out? The USDA has information on their website but it isn't as clear as it could be. I wrote about pesticide residues a while back in response to the "Dirty Dozen": Details on the Dirty Dozen. Sadly, the EWG has done a lot of damage with the DD list in convincing people that any residue is bad while conveniently ignoring many organic pesticides that have not even been tested for safety.

    Almost always means an average of 1.6% of samples tested by the USDA have a positive pesticide detection that is higher than the allowed safety limits. In many cases, these were only slightly above the limit. The allowed safety limits are 10x to 1000x higher than what has been found to cause problems at acute or chronic levels in animal testing. More than 1.6% of samples do have detectable levels but that's only because we have crazy sensitive tests.

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    1. I think that consumers distrust the levels set as "safe," not that they necessarily don't understand the science behind it. A particular issue is the way toxicological testing is done and the stages/routes/U-shaped dose response potentials that aren't actually addressed in standard toxicological testing.

      Obviously, people I know who buy organic because of what they hear about pesticides weren't doing so with some kind of prescience about the findings of this study; by "that finding alone," I meant that concerns about pesticide residues in general are a driver.

      What dog in the hunt does the EWG have to "conveniently" ignore some types of pesticides while excoriating others? What do they get out of that? Serious question.

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  5. My reasons for organic (the last few years anyway) is primarily a probability choice: it's more likely that a random organic product was less harmful environmentally than conventional (though other studies have me doubting). Big long post on my blog but that's the gist of it.

    That said, I was pretty sure at least some people really did think organic food was more nutritious -- not just "healthier" which could include worries about pesticides or microbes. Apparently somewhere around half of Americans do -- http://www.usatoday.com/news/health/story/2012-09-03/organic-food-health/57557912/1. I admit that shocked me (higher than I expected). I'd seen organic producers push the line based on studies that primarily looked single foods or groups (e.g. high omega-3 eggs). Though less surprisingly the poll says more choose organic to avoid pesticides. The world is at least somewhat reasonable. :)

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