I'm feeling a little distressed over the tone that's been set this morning over the study that states "organic" food is not any more nutritious than "non-organic". The coverage almost has felt like we blew a hole through a mythical story that organic foods are so much better for us. That's certainly not what the study means.
Forgive me, but nutritional content is an interesting question by itself, but there were no shocking insights revealed. Rather, the fact that organic and non-organic foods are about equal is an outstanding result! Choosing organic does not mean that you're sacrificing nutritional value and that is a big deal.
I'm a botanist by training, so I'm going to use a plant example.
A wheat crop growing in a field is going to take up water and micronutrients from the soil, and will gain it's carbon content from the air through photosynthesis. Sure, that's a little simplified (the plant will take in some water through pores - called "stomates" - in its leaves) but it's a rather good starting point.
"Organic foods" are foods that are grown according to set standards. Synthetic pesticides, chemical fertilizers, chemical ripening agents (except ethylene), food irradiation, and genetically modified organisms are unacceptable in organic foods. Importantly, naturally occurring pesticides are permitted, as is the use of ethylene which plants use as a natural ripening plant hormone. What the study looked at was a link between whether those chemical factors impacted nutritional quality.
Off the top of my head, I have questions regarding the nutritional value of organically certified foods. Does the addition of chemical fertilizer boost the nutritional content of the wheat kernels? Nitrogen content is usually the limiting factor, does more nitrogen availability mean a heather grain? Alternatively, adding chemical fertilizer may actually over-compete for micronutrient adsorbtion from the soil and lead to less nutritious grain, although I would consider that a less likely (but clearly possible) result.
The most important point the study makes is that all the questions I just raised are not major factors in the nutrition of foods. Barring further information, the food we eat can be healthy and nutritious whether or not it has been certified organic.
The biggest difference in cost between organically certified foods and non-organically certified foods generally results from differences in yield. Chemical fertilizers do permit more growth of the plant and that extra growth is passed along into extra seed production. This is even more pronounced in something like lettuce where we are actually eating the leaves. More production means more value can be obtained from the same amount of land. Clearly we have been able to advance fertilizer knowledge enough so that the yield increases are worth the increased cost of adding chemical fertilizers.
Just to restate myself, there does not appear to be any measurable difference in quality of organically certified foods and foods which are not organically certified! We do not have to choose one or the other for direct nutritional benefits. More is produced through current farming practices but it is, by and large, no better and no worse with respect to nutrition.
However, the next important question was mentioned by has not been addressed by the study. The exposure to chemical pesticides is nearly one third lower in organically certified food. It is important to look at which pesticides are most commonly contained in the food material. It is important to look at how the plant takes up the pesticides. It is important to examine the effects an increased exposure could contain.
Pesticides are any substance or thing that kills a pest. That pest could be plant or animal. If an animal, it could be insect, bug or deer. The arrow a hunter used to kill the elk that was eating your roses could be considered a pesticide! But that would not be considered a chemical pesticide, it clearly would not be passed along in the plant, and it would hardly be of concern to us. ("Oh, someone slipped an arrowhead into my salad!") On the other hand, cyanide used to kill rats mixing in with your breakfast cereal would be a major pesticide concern. It's a very broad statement, more clarity needs to come with which specific pesticides are being transmitted in our food and what the impacts may be.
Further questions go on an even more granular level, which probably won't be of interest to the general public yet. When we spray pesticides across a field, most of them work by foliar application - contact with leaves. What is their mode of action on the pest? (Do they work on a chemical pathway that only affects plant biochemistry?) Do they enter via the stomates? Are they translocated? (Are they moved throughout the entire plant, and therefore into the seeds, or do they only function at the leaf?) There is a wide range of really important, botanically nerdy questions that follow from that.
The biggest take home message I get from this article is, stated as simply as I can, nutritionally it does not make a difference whether I choose organically certified or not organically certified foods. I'm not panicking over what I purchase, but I try to be objective. I tend to believe the best nutritional value and flavour comes from fresh foods, so I generally prefer food which has been produced nearby. In the case of something like bananas, I have no locally produced option. If costs are similar, I tend to choose organic options on the belief that I reduce pesticide exposure and believe organic food production tends to be a more sustainable practice in general. (Granted, I usually have no idea whatsoever of the conditions the food was actually produced in, but I hope that choosing organic food would help make the argument that sustainable agriculture is worthwhile.)
Food I produce in my own garden is entirely organic. I will not see yield increases that justify buying fertilizer. I could use pesticides within recommended limits, but I'd never produce anything on a scale to make it really worthwhile. It's simply easier to garden organically.
I am not harming myself nutritionally when I choose organically certified food vs. non-organically certified food. My preference can then be made based upon further factors. It is reasonable to choose, now look into your food and choose based upon good reasoning.