Health of organic vs non-organic dried beans.
I am writing you today because I am a RD (registered dietitian) and have received many consumer questions about the safety of eating dried beans that are NOT organically grown. There are many new varieties of heirloom beans being sold that consumers are interested in. But, the companies that grow and/or distribute them are not selling organic beans. My understanding is that not a lot of fertilizer and/or pesticides are needed/used to grow dry beans in the first place. And that because beans grow inside a bean pod they are safe from contaminants. I appreciate your kind reply, so I can accurately answer questions about the safety of eating non-organic dried beans.
Benton County Oregon fruits and vegetables
Good morning, and thank you for your inquiry. A very interesting question, indeed.
I did a quick literature review, and as you might imagine, the findings are all over the board when it comes to the nutrition benefits of organic produce vs conventionally grown produce. There have been a number of studies done over the years, usually with fresh vegetables. I could not find any references to dry beans.
I found one review article in the American Journal of Clinical Nutrition that you may want to reference and that probably sums it up best http://ajcn.nutrition.org/content/92/1/203.short. The authors conclude that there is not a lot of evidence that organic is more nutritious than conventional. Studies are initiated and reported occasionally and this is my recollection as well; some say yes, some say no.
One thing to keep in mind when reading these studies is that organic produce is often grown under stressful conditions, meaning that insects and disease may be doing more damage than in conventional production, or perhaps essential nutrients are in shorter supply. This may mean that the plant has a higher anthocyanin content (think anti oxidant, more color). In one study I remember seeing (I think, but could not locate) nutrient density was greater than in conventional produce, and that would match my own observations.
The other issue to consider is pesticide and fertilizer use. Your are correct, dry beans 'make' their own nitrogen, and in general fertilizers are less important for production than in crops like broccoli or sweet corn.
As for pesticide residues in beans, the EPA regulates what is applied to beans, and stringent studies are conducted so that consumers can be guaranteed that they are not exposed to unsafe pesticide residues. And just because a crop is organically grown, does not mean that pesticides are used. It just means that the pesticides that are used are natural, not synthesized. The FDA monitors pesticide residues in food annually and you can reference their report at http://www.fda.gov/Food/FoodborneIllnessContaminants/Pesticides/ucm2006797.htm. I doubt that dry beans are on the list every year, but it might be worth a look.
Please let me know if I can be of more assistance.