When I arrived in South Carolina this September, one of the first things my aunt told me over a meal was something like, “Well, did you hear the news that organic food is not that healthy after all—it doesn’t make any difference!” I was surprised and intrigued, especially since she had heard the story on the cable news. Let me be clear, I’m a big believer in organic foods and have eaten a mostly organic diet for upwards of 25 years. My aunt, on the other hand, comes from a generation that just doesn’t get why someone would chose to pay double the cost or more for food—especially vegetables.
After my aunt’s announcement, as the days went by, controversy blew about, with folks from both sides arguing their points. The news coverage I heard implied that the Stanford University study had found no evidence that organic foods were any safer or more nutritious than conventionally grown foods. I just had to see what this study actually said, so I went on down to the UCSF Medical Library, which if you didn’t already know is a public library where you can get free access to health science papers in their entirety.
The paper reporting the results of the study begins its discussion with this tepid statement:
“Consumers purchase organic foods for many reasons. Despite the widespread perception that organically produced foods are more nutritious than conventional alternatives, we did not find robust evidence to support this perception.”
The paper concludes:
“In summary, our comprehensive review of the published literature on the comparative health outcomes, nutrition, and safety of organic and conventional foods identified limited evidence for the superiority of organic foods. The evidence does not suggest marked health benefits from consuming organic versus conventional foods, although organic produce may reduce exposure to pesticide residues and organic chicken and pork may reduce exposure to antibiotic-resistant bacteria.”
Not exactly a blanket statement of no evidence of benefit, is it?
In the actual findings, they report that:
- organic produce had higher levels of total phenols (things like reservatrol, tocopherol and anthocyanins which are anti-oxidants)
- organic milk and chicken contained larger amounts of Omega 3 fatty acids
- conventionally raised chicken and pork had a higher risk of contamination from bacterial strains resistant to 3 or more antibiotics
- conventionally grown produce had a 30% greater risk of pesticide contamination
In a New York times article written on October 15, reporter Kenneth Chang compared this Stanford study with another recent study from New Castle University in England, both of which used the same methodology—a meta-analysis which basically aggregates data from many individual studies to build a large data pool to look for significant results that have more “strength”. The interesting thing is that both studies examined virtually the same data, but came to different conclusions, with the New Castle study finding stronger evidence for the nutritional superiority and safety of organic foods. Chang reports that the decisions each group of scientists made about how to account for and handle data coming from studies that did not use the same methodologies resulted in the different outcomes. Many of the experts he interviewed indicated that there was precedent for the decisions made by both sets of scientists. The problem, as you can already see, is that these decisions resulted in differing conclusions.
The take-home message here, I think, is two-fold. First and most important—don’t believe the hype! News coverage of science is notoriously bad, mostly because news coverage is geared towards fast conclusions, just the opposite of the way science works. In science, each study is just another brick in a wall of evidence. Ultimately, the whole wall must be taken into account, not the individual bricks, and the wall of evidence takes many years and bricks to build. Often the wall is full of bricks reporting contradictory results, which, again, takes many years to correctly interpret. And, as demonstrated in coverage of this story, the actual conclusions of studies are usually nowhere near as provoking as reporting that organic food is not any better for you than conventionally grown food. It’s always worth remembering that news organizations are in the business of getting your attention.
Secondly, the case for organic foods is not generally about whether the foods are more nutritious for you but about pesticide exposure. The Stanford study did find that conventionally grown foods are 30% more likely to be contaminated with pesticides. And the truth is that we just don’t know what this means for our health. We do know that certain levels of exposure are toxic. Those levels are probably different for each individual depending on their genetics, their age, their general health and the build-up of exposure. Many pesticides are made from fat-soluble molecules and end up stored in our own fat tissue potentially magnifying our exposure level. And, those who work on the farms using pesticides and the plants and animals living around them are chronically exposed.
Personally, I’m not interested in participating in the long-term, uncontrolled experiment our nation is conducting with pesticides. And I believe that because I can make this choice, it’s my responsibility to help support farmers who grow organic food. Why? Because it not only reduces my risk, but the risk to all those involved in growing the food and to the entire eco-system that, truth be told, sustains all of us. There’s an Ayurvedic proverb that says, “Our lives are not in the hands of the Gods, but in the hands of our cooks.” The raw materials of cooking come from the hands of our farmers. Our choices about what type of food to buy influence the choices our farmers make about how to grow our food—we make a difference. Do we support systems that depend on synthetic pesticides and antibiotics, or do we choose to support systems that minimize them?
Chang, Kenneth. (October 15, 2012) Parsing of Data Led to Mixed Messages on Organic Food’s Value. New York Times. Available at: http://www.nytimes.com/2012/10/16/science/stanford-organic-food-study-and-vagaries-of-meta-analyses.html
Smith-Spangler, C., Brandeau, M.L., Hunter, G.E., Bavinger, C., Pearson, M., Eschbach, P.J….Bravata, D.M. (September, 2012) Are Organic Foods Safer or Healthier Than Conventional Alternatives? A Systematic Review. Annals of Internal Medicine. 157(5):348-366