Quick Hit Summary

Within the past 15 years, the organic food industry has exploded. Most proponents of organic foods claim that it has higher nutrient content than traditionally grown crops. However, recent research indicates that this may not be the case. One large study indicated that no difference existed between 11 of 13 micronutrients (vitamin C, calcium, potassium, etc) tested between organic and conventionally grown foods. The freshness of a food product, rather than growing style (organic vs. conventional) appears to play a larger role on nutrient content. The much larger issue to keep in mind is that organic food hasn’t been contaminated with pesticides, etc. For this reason, I recommend purchasing organic foods when feasible.

The Organic Boom

Organic Food⁵

Before the end of the 90’s, the only people who talked about “organic” compounds were chemists and other members of the scientific community. For these individuals, organic simply refers to any form of matter (solid, liquid, gas) that contains the element carbon. However, within the last 5-10 years, this term has slipped out of classrooms/science labs and into the household. In the process it has picked up a whole new meaning that refers to the process of producing natural, chemical free food. Now, almost every major grocer has organic food sections. In fact, some grocers, such as Whole Foods Market®, specialize in nothing but natural and organic foods.

Nutrient Content in Organic vs. Conventionally Grown Food

Proponents of organic food often claim that it has superior nutrient content vs. its conventionally produced counterpart. However, in a recent systemic review of the literature, Dangour et al. found very little difference between nutrient content of organic and conventionally grown crop products (vegetables, fruit) or livestock¹. Using rigorous exclusion criteria (read article for detailed explanation), they found 55 studies that directly compared nutrient content of organic and conventional methods of food production. With respect to crop products, only 11 nutrient categories (see list below) were included in > 10 of the reviewed studies. There were no significant differences between 8 of the 11 nutrients. Significant differences were only seen in nitrogen (> in conventional), phosphorous and titratable acidity (both > in organic). See Table 1.

Table 1. Comparison of various nutrients between organic & conventional food products. Information obtained from Dangour et al.¹

Nine studies involving animal livestock-products were included. Of these 9 studies, only 2 nutrient categories (fats, ash) were included in > 4 of the reviewed studies. Analysis of the combined data indicated that there weren’t any significant differences in fat or ash between production methods.

What does this all mean?

According to the results of this study, there does not seem to be any major differences in the nutritional content of conventional vs. organic products with respect to the 11 nutrients analyzed. Besides this study, I’ve read numerous research articles examining the nutritional value of these production methods. Overall, results tend to go back and forth.

The determining factor of nutrient content might have more to do with the freshness of the product rather than if it’s organic or conventionally grown. For example, one study looked at vitamin C content of organic vs. conventionally produced broccoli². This study included broccoli that was harvested locally (fresh during the fall) or shipped in from other areas during the non-growing season (spring). Results indicated that no difference was present between vitamin C content of organic and conventionally grown products when obtained at the same time of the year. However, a significantly greater amount of vitamin C was present in broccoli (regardless of production method) grown locally vs. that shipped from a distance. In conclusion, the investigators stated that freshness of broccoli, rather than type of broccoli (organic vs. conventionally grown) had greater impacts on nutrient content.

I recommend that everyone eats a diet containing fresh fruits and vegetables. Thus, I’m not super concerned about organic foods for their nutrient content. My larger concern has to do with what’s NOT present in organically grown crops and livestock: synthetic pesticides, herbicides, etc. I think anytime you can stay away from those chemicals, your overall health will benefit. Although it would be great if all the food we ate was organic, at times this may not be feasible for financial reasons. Therefore, one may be best to “selectively” choose which foods to buy organic vs. conventional. Luckily for us, the Environmental Working Group (EWG) has compiled a list of foods most/least likely to be contaminated with pesticides. See Table 1. This list was compiled based off reports and analysis carried out by the USDA. To understand how the EWG’s methodology in understanding the reports CLICK HERE.

Table 2. Foods most/least likely to be contaminated with pesticides according to the Environmental Working Group³.

According to the EWG, eating 5 fruits and vegetables/day from the 12 most contaminated items will expose an individual to ~10 pesticides/day⁴. In contrast, individuals who eat 5 items from the least contaminated fruits/vegetables will be exposed to <2 pesticides/day. As a FYI, prior to analysis, all food products was washed, similar to what one would do at home before eating it.

Bottom Line

Research conducted by Dangour et al. indicates that organic and conventional products have similar levels of 11 different vitamins & minerals (see Table 1). Freshness, rather than growing style (organic vs. traditional) may play a larger role on the nutrient quality of the food.

I recommend eating a variety of fruits and vegetables. Thus, I’m not overly concerned with if a certain growing style slightly affects the micronutrient content of the food. I’m more concerned with the chemicals sprayed on crops that end up in our food or run off and pollute our water system. Although I’d feel better about eating all organically grown food, due to cost issues, this is not feasible for me. Thus, I try to limit my intake of conventionally grown fruits/vegetables that rank high on the EWG’s pesticide exposure list.

In conclusion, it’s still being debated if organic or conventionally grown is more nutrient packed. However, the bigger issue that we should be concerned with is exposure to pesticides, etc, found in conventionally grown food. Therefore, I recommend eating organic food as a means to reduce exposure to contaminants.

UPDATE – Sept 7, 2012 My Friend Dr. Moussa at Suppversity wrote a nice update on this discussion which can be found by clicking HERE

Whole Foods Market is a trademark or registered trademark of Whole Foods Market IP, L.P.

Reference

¹ Dangour AD, Dodhia SK, Hayter A, Allen E, Lock K, Uauy R. Nutritional quality of organic foods: a systematic review. Am J Clin Nutr. 2009 Sep;90(3):680-5. Epub 2009 Jul 29.

² Wunderlich SM, Feldman C, Kane S, Hazhin T. Nutritional quality of organic, conventional, and seasonally grown broccoli using vitamin C as a marker. Int J Food Sci Nutr. 2008 Feb;59(1):34-45.

³ The Full List: 49 Fruits and Vegetables. EWG’s Shopper Guide to Pesticides.2007-2010. Accessed May 14, 2010 from: http://www.foodnews.org/faq.php.

⁴ Shoppers Guide to Pesticide. EWG’s Shopper Guide to Pesticides. Environmental Working Group.2007-2010. Accessed May 14, 2010 from: http://www.foodnews.org/EWG-shoppers-guide-download-final.pdf.

⁵ Photo uploaded by ntoper. Accessed June 13, 2010 from: flickr.com/photos/ntoper/3678037946/