This month had the publication in the Annals of Internal Medicine a review or meta-analysis of 237 studies regarding organic vs conventional foods with the purpose to:
"…comprehensively synthesize the published literature on the health, nutritional, and safety characteristics of organic and conventional foods."
The Stanford group looked at two general distinctions:
1) What were the health outcomes of eating organic vs conventional foods to humans. Specifically, they looked at literature that found medical complications associated with organic vs conventional foods, pesticides found in fluid components (urine etc), and markers of improved health such as immune or antioxidant markers.
2) The second group, and which constituted 223 of the 237 studies, looked at the vitamin and nutrient values of the foods, residual pesticide contamination, bacterial contamination, and antibiotic resistance in meats.
The findings were fairly underwhelming for me but seem to have caused controversies in the news media questioning why we should eat organics based on this study.
Here are a few thoughts about “news.” Check your sources and check their sources and best yet, go to the source. With just a bit of thoughtfulness, you can read journal articles and start to understand why each article must always be held in some suspicion.
What were the results?
1. There were no clear improvements in some health outcomes (eczema, allergies etc)
2. Urine pesticides in children were lower in organic group
3. There was no vitamin difference between the groups.
4. The only nutrient differences were in phosphorous and phenols.
5. Possible higher levels of omegas in some organic foods though this often depended on the brand.
6. Organic foods had a 30% lower risk of being contaminated with pesticide residues.
7. No meat bacterial contamination differences were noted (though a few studies pointed towards organics having higher rates on bacteria). None were dangerous.
8. Antibiotic resistance was 33% higher in conventional meat.
A few things about this study:
The study admits most of the original data they looked at had “fair” quality only. Meaning the original research lacked important information. The one I noticed most was a lack of description of the organic methods used to grow the food. For both health and nutritional values, about 50% of studies did not clarify what organic methods were used. We know that “organic” varies a lot from farm to farm and country to country. Secondly, about 50% of the studies were from experimental farms - not real world comparisons, meaning they might or might not be true in the real world. Third, USDA has often identified dozens of pesticides on foods, the study here only reported on a handful and measurement and sampling methods (ie how the pesticides were measured and recorded) were not reported.
To me, however, the question I’m left with is not whether the apple grown on a regular farm is more nutritional than the apple that is organically grown - it never really was. My question is what does it mean to be exposed to pesticides? The study did not address this question and therefore the study didn’t help me understand my risks or benefits of eating organic vs conventional foods. How do I weigh the costs, the lack of information, my ethics, my concerns about health, lobby interests etc? I use common sense and do my best. If I can peel it, then get it conventional, if it’s not horribly more expensive and has a thin peel or none at all, invest in organic.
In the end, I come back to the EWG listing of the Dirty Dozen and Clean 15 - a yearly listing based on USDA research of what level of pesticides are left on food when cleaned thoroughly. Find the full list here:http://www.ewg.org/foodnews/