In the fall of 2012, it was all over the media: organic food is no healthier than conventional. A study from the prestigious Stanford University said so, so it must be true, right? Not so fast. The Stanford study only compared a few aspects of organic versus conventional which allowed them to make some limited conclusions. As it frequently happens, what the study said and what was widely reported were quite different. Let’s tease out what it really found and what it did not address.
Before you get mad at the authors or the study itself, consider the study’s actual conclusion: “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.”
As a naturopathic physician in clinical practice, I don’t recommend my patients choose organic foods for their nutrient density. No, for that, I counsel them on how to eat a whole foods diet. I recommend organic foods for precisely the reason the authors suggested: lower exposure to pesticides and antibiotic-resistant bacteria. This is significant, especially in pregnant women, infants and children. And they did find that eating organic reduced the measurable pesticides in children. There were no studies looking at this in adults. In fact, according to the authors, “these are some of the most important findings of our study.” Somehow, though, these findings did not make the headlines.
The Stanford study was a meta-analysis, which means it did not do any original research, but compiled and compared results from a of number previous studies – 237 to be exact. Most looked at differences between conventional and organic foods. Seventeen were studies in humans, and of these, only three studies looked at clinical outcomes – that is, actual effects on health rather than markers like cholesterol levels. These did not find a difference between eating primarily organic rather than conventional foods in terms of risk for eczema and allergies. However, I’m not sure anyone thought organic foods decreased the risk for eczema or allergies to begin with.
Also, these three were short-term studies, which makes them much less meaningful. In a sense, being exposed to background levels of toxic chemicals is like smoking tobacco, eating a poor diet, or regularly drinking too much alcohol. We don’t expect most people to fall ill from eating conventional apples for 2 days, 2 weeks or 2 months. In order to accurately assess the long-term health impact, we need long-term studies. Unfortunately, we don’t have them, so we just don’t have a clear answer to this question. However, we do know that cleaner living supports better health. We have lots of information that shows the opposite – toxic exposure leads to illness. In fact, in 2010 the President’s Cancer Panel recommended reducing exposure to environmental toxins by choosing “food grown without pesticides or conventional fertilizer,” in order to reduce risk of cancer.
Previous work has found organic food is indeed more nutritious. But even if that turns out not to be the case, there are still plenty of reasons to pay extra for organic. The authors themselves recognized that “there are numerous valid reasons why consumers might choose organic over conventional foods, including concerns about the environment, animal welfare, farm worker health, taste and cost.” I would add avoiding toxic exposures to this list. (And perhaps remove cost, since organic tends to cost more).
If eating organic is just too expensive, have a look at the Environmental Working Group’s Annual Shopper’s Guide. Here you can look at their ratings of which produce have the highest and lowest levels of pesticide residues, so you can choose to buy organic where it matters most – the foods with the highest pesticide residues.