July 2013 Issue

The Organic Foods Debate — Are They Healthier Than Conventional?
By Judith C. Thalheimer, RD, LDN
Today’s Dietitian
Vol. 15 No. 7 P. 28

Many consumers believe organics are healthier than conventional options, as studies show some organics contain more nutrients and significantly less pesticide residues that research suggests may be harmful to your health.

“Should I buy organic?” As dietitians, you’ve probably heard this question from clients time and again. Given the higher cost of organic foods and new questions being raised regarding their health benefits, clients are right to ask.

Despite these new questions, however, demand for organic products is growing. According to the Organic Trade Association’s (OTA) 2012 Organic Industry Survey, sales of food and nonfood organic products grew by 9.5% in 2011 to reach $31.5 billion.1 Of the 81% of families that said they bought organic food products, as part of the OTA’s newly released 2013 US Families’ Organic Attitudes and Beliefs Study, 48% said their primary motivation was the belief that organic products are a healthier choice for themselves and their children.2 But are organic foods, in fact, more healthful than conventional foods?

Finding the Truth
A meta-analysis conducted by Stanford University researchers and published in the September 2012 issue of Annals of Internal Medicine touched off a media firestorm when it concluded that “the published literature lacks strong evidence that organic foods are significantly more nutritious than conventional foods.”3 With the exception of higher phosphorus levels in organic produce and limited evidence suggesting higher omega-3 fatty acids in organic milk, no significant difference was found between the nutrient levels in organic and conventional foods.3

Similarly, a 2007 meta-analysis by the British Nutrition Foundation found no overall differences in the nutrient profiles of organic and conventional foods. However, there was evidence of higher levels of vitamin C in some organically grown produce, such as potatoes and dark, leafy greens.4

Mary Ann Moylan, RD, LDN, CDE, an in-store dietitian for Ahold USA’s Giant Superstore supermarket in Willow Grove, Pennsylvania, has seen firsthand the impact of the media surrounding the Stanford study. “More customers are asking me about the benefits of organic foods,” she says. “They want to know what I think. As a registered dietitian, I need to be able to answer these questions in an informed and evidenced-based way.”

Comparative analysis of plant nutrients is complicated. A plant’s nutrient profile depends on the plant species or variety, weather during that particular growing season, soil makeup, and other conditions. In studies that compare the same varieties of fruits and vegetables grown in similar locations, organic food contains higher levels of some nutrients about 60% of the time, according to Charles Benbrook, PhD, a research professor at Washington State University’s Center for Sustaining Agriculture and Natural Resources.5

While the Stanford analysis averaged crops from multiple years into a single data point, a 2011 review that looked at separate years as separate data points to account for the effects of weather came to a very different conclusion.6 The 2011 review, a meta-analysis conducted by scientists at Newcastle University in England, concluded that organic produce has a 12% higher content of secondary metabolites and a 6% higher vitamin C content than corresponding conventional samples.6 Secondary metabolites are phytochemicals that increase a plant’s ability to survive in its environment. Since organic plants are forced to defend themselves against disease and pests without the aid of manmade chemicals, they may develop more of these natural defenses.

The Newcastle researchers posited that the defense-related secondary metabolites in fruits and vegetables are the reason higher intake is linked to reduced risk of cancer and cardiovascular disease. While it’s possible that higher levels of beneficial phytochemicals and vitamin C make organic foods better for our long-term health outcomes than conventional products, there have been no large studies in humans to address this issue.6

What Is Organic?
When examining the value of organic foods, it’s important to understand the definition of organic. In the United States, organic is a labeling term defined by the USDA. To be considered organic, a product must meet federal standards for production, processing, and certification under the Organic Food Production Act of 1990. The National Organic Program oversees these standards, which have been in full effect since October 2002.

According to the USDA, organic products have “been produced through approved methods that integrate cultural, biological, and mechanical practices that foster cycling of resources, promote ecological balance, and conserve biodiversity.”7 The national organic standards forbid the use of synthetic fertilizers and pesticides, sewage sludge, irradiation, and genetic engineering to grow fruits, nuts, vegetables, and grains. Organic meat and poultry can’t be irradiated. The animals must have access to the outdoors, and they can’t be given any growth hormones, antibiotics, or other drugs. All feed must be 100% organic, with no animal by-products.8

“The most important aspect of this conversation is that organic produce is about much more than nutrients; it’s about the way crops are grown,” says Sharon Palmer, RD, author of The Plant-Powered Diet. “Organic produce generally has lower levels of pesticide residues, which is one of the main reasons people are attracted to them. In addition, organic production is more sustainable; it uses less energy, produces fewer greenhouse gas emissions, and creates healthier soils. If anything, this widely publicized [Stanford] study highlights what’s really important about organic food production; it’s not just the nutrients.”

Reasons for Buying Organic
The 2010 Nielsen Global Online Survey found that worldwide people buy organic foods for more than just their perceived vitamin or phytochemical content. North America was the “region most likely to buy organics to avoid toxins (71%), promote environmentally friendly organic farms (59%), help small farmers (58%), avoid genetically modified products (45%), do the right thing (38%), and vote against modern farming methods (23%).”9

Moylan says her customers choose organic foods for a variety of reasons: “Some prefer the taste of organic produce or milk. Others are interested in protecting the environment or want to support sustainable agriculture. Food safety and the use of chemicals in food manufacturing are common concerns. I see a particular interest from pregnant women and people with young children.”

Evidence for some of the benefits of organic foods can be found in the Stanford study. The researchers reported evidence of pesticide residues in 38% of conventional foods and 7% of organics. In absolute terms, organic fruits and vegetables had a 30% lower risk of pesticide contamination than conventional produce.3

While farmers can’t apply synthetic pesticides to organic produce, there can be what the USDA calls “inadvertent or indirect contact from neighboring conventional farms or shared handling facilities” as long as the level of prohibited pesticides remains below 5% of the accepted tolerance levels.10 In the 2013 US Families’ Organic Attitudes and Beliefs Study, 30% of families cited limiting exposure to pesticides as a reason they buy organic foods.2

In the Stanford study, pesticide levels in conventional foods generally fell within the Environmental Protection Agency’s (EPA) acceptable limits.3 Despite the EPA’s control of residue levels, concerns still exist about the safety of ingesting pesticides, especially in adults with chronic health conditions, children, and pregnant women. Studies have shown that eating organic foods reduces pesticide exposure. A 2003 study by Curl and colleagues found that children aged 2 to 5 who ate conventional foods had six times more urinary organophosphorus pesticide metabolites than children who ate organic foods.11 Three studies funded by the National Institute of Environmental Health Sciences and the EPA found that women with higher pesticide exposure during pregnancy had children with lower IQ scores.12

Moreover, the detrimental environmental impact of pesticide use should be taken into account. Air- or water-borne pesticides can deplete the ozone, harm or kill nontarget species and beneficial soil organisms, contaminate drinking water, or adversely effect marine life.

Twenty-nine percent of families who buy organic foods are concerned about hormone and antibiotic use in conventional foods.2 The increase in antibiotic-resistant bacterial infections in humans primarily is a result of unnecessary antibiotic use in both humans and animals. On conventional farms, low levels of antibiotics routinely are used in healthy animals to speed up growth and discourage the development or spread of bacterial disease. In 2011, about 80% of all reported antibiotic sales in the United States were for use in livestock (29.9 million lbs for animals vs. 7.7 million for humans).13

The Stanford study found that, while bacterial contamination was common in chicken and pork regardless of farming method, conventional chicken and pork had a 33% higher risk of contamination with bacteria that was resistant to three or more antibiotics than organic products. There was no difference in the risk of E coli contamination between organic and conventional produce.3

The 2011 report by the National Antimicrobial Resistance Monitoring System found that more than 27% of all bacteria isolated from chicken showed resistance to five or more classes of antibiotics. Researchers also found 10 different serotypes of bacteria resistant to six or more classes of antibiotics in ground turkey. Fifty-five percent of Salmonella isolated from retail poultry was drug resistant, up from 50% in 2010.14 In 2012, the FDA restricted the use of the cephalosporin class of antibiotics in animals in response to rising resistant strains of bacteria.15

Advising Clients
When answering clients’ questions about organic foods, dietetics professionals clearly must take into account a definition of healthy that goes beyond nutrient content. “I think it’s important for RDs to discuss the whole situation about organics, not just nutrients. We should feel informed and empowered to discuss the entire food system in our conversations with people,” Palmer says. “Dietitians should be the experts in areas such as food sustainability and production. Otherwise people will turn to less informed people for information about organics.” For evidence-based information on organics, Palmer recommends the Hunger and Environmental Nutrition Dietetic Practice Group of the Academy of Nutrition and Dietetics (the Academy).

It’s important to recognize that organic products may be hard to find in some areas. The good news for those seeking organic products is that they’re more available now than ever. In 2010, natural retailers sold 39% of all organic foods, and 54% was sold by mass-market retailers such as mainstream supermarkets, club/warehouse stores, and mass merchandisers.16 Many mainstream retailers today offer their own line of natural and organic foods, use shelf tags to promote natural and organic choices throughout the store, or devote a section of the store to these products. Moylan sees the impact of this trend firsthand. “The customers I counsel at Giant are pleasantly surprised to see how many items throughout the supermarket have those purple ‘organic’ food tags, and grouping items in our Nature’s Promise Marketplace has been a big help to customers looking for those options. Having programs like these in mainstream markets is really broadening options for the average shopper.”

The growing availability of organic products is fueled by studies showing that organic buyers are spending more per shopping trip and are shopping more frequently than those who never purchase organic food. Organic buyers spend more because organics can cost 20% to 100% more than their conventionally produced counterparts. Many factors lead to the higher cost: Growing crops without herbicides and pesticides causes more losses from crop damage and incurs higher labor costs for weeding and pest control; animals raised to produce organic meats must be fed more expensive organic feed; and there’s a fee for organic certification.17

If price is a concern, Vandana Sheth RDN, CDE, a spokesperson for the Academy, recommends choosing fruits and vegetables that provide the most potential health benefit for the money. “The Environmental Working Group tests more than 10,000 pesticides in fruits and vegetables and develops a Dirty Dozen list,” she says. “Conventionally grown versions of these fruits and vegetables have been found to have higher levels of pesticide residue.” The group also publishes The Clean 15, a list of the 15 conventionally grown fruits and vegetables found to have the least pesticide residues18 (see Table 1). The FDA recommends washing all fresh produce, organic as well as conventional, for food safety reasons and to reduce or eliminate pesticide and fungicide residues.19

Moylan counsels customers on a budget seeking organic choices to begin with foods they eat most often or in the greatest quantities. “Choosing organic produce in season is a great way to stretch your organic foods budget too,” Moylan says. “They’re more likely to be locally grown and cost less to transport, leading to lower prices in the store.”

Palmer suggests looking outside traditional stores and making wise choices. “There are more affordable ways to eat organic, such as using your farmers market and community-supported agriculture programs to purchase foods that may be grown in an organic fashion but not necessarily with the certification. Don’t waste money on purchasing organic junk food [eg, cookies, chips, candy]. I see that as a waste of food dollars. You also can find less expensive organic foods at stores that specialize in it rather than stores that have a small selection,” she says. Buying in bulk and what’s on sale, using coupons, and purchasing the growing number of private label brands are other money-saving ways to buy organic.20

What Really Matters
Whether people buy organic or conventional, it’s the nutritional quality of the overall diet that matters. “The key is to enjoy a wide variety of foods, including fruits, vegetables, whole grains, lean protein, nuts, seeds, and beans,” Sheth says. “I advocate that people meet their fruit and vegetable servings as their primary goal,” Palmer adds, regardless of whether that produce is organically grown.

In November 2012, the American Academy of Pediatrics (AAP) published a clinical report on the health and environmental advantages and disadvantages of organic foods. The report concluded with advice for pediatricians, which nutrition professionals can use as a guide as well. In summary, the AAP recommended encouraging a health-promoting diet; answering questions about organics using the latest scientific evidence regarding nutrition, cost issues, and the environmental impact; and directing clients who express concern about the potential health impact of pesticide residues in food to resources such as the Environmental Working Group’s “Shoppers Guide to Pesticides.”21

“Choosing to buy organic foods is a personal decision,” Sheth says. “At this point, there’s no conclusive scientific evidence that shows that organically produced foods are healthier. Similarly, taste and appearance of organic or conventionally grown foods don’t show a significant difference. If your goal is to limit your exposure to pesticides, antibiotics, and hormones or if you have concerns about environmental impact, look for the organic label on foods.”

— Judith C. Thalheimer, RD, LDN, is a freelance nutrition writer and community educator living outside Philadelphia.


7 Ways to Reduce Pesticide Residues
The FDA offers the following tips to reduce or eliminate any pesticide residues and bacteria that may be present on conventional or organic produce and meats1,2:

Wash your hands for 20 seconds with warm water and soap before and after preparing fresh produce to prevent the spread of bacteria.

Cut away any damaged or bruised areas before preparing or eating.

Wash produce with large amounts of cold or warm running tap water and scrub with a brush when appropriate. There’s no need to use soap or a produce wash.

Wash produce before you peel it so dirt and bacteria aren’t transferred from the knife onto the fruit or vegetable.

Dry produce with a clean cloth or paper towel to further reduce bacteria that may be present.

Throw away the outer leaves of leafy vegetables such as lettuce and cabbage.

Trim the fat from meat and the fat and skin from poultry and fish. Residues of some pesticides concentrate in animal fat.

Sidebar References
1. 7 tips for cleaning fruits, vegetables. US Food and Drug Administration website. http://www.fda.gov/ForConsumers/ConsumerUpdates/ucm256215.htm. Updated April 12, 2013. Accessed April 25, 2013.

2. Pesticide Q & A. US Food and Drug Administration website. http://www.fda.gov/Food/FoodborneIllnessContaminants/Pesticides/ucm114958.htm. Updated February 20, 2013. Accessed April 23, 2013.


Main Article References
1. Consumer-driven US organic market surpasses $31 billion in 2011. Organic Trade Association website. http://www.organicnewsroom.com/2012/04/us_consumerdriven_organic_mark.html. April 2012. Accessed April 18, 2013.

2. Eight in ten US parents report they purchase organic products. Organic Trade Association website. http://www.organicnewsroom.com/2013/04/eight_in_ten_us_parents_
. April 4, 2013. Accessed April 17, 2013.

3. Smith-Spangler C, Brandeau ML, Hunter GE, et al. Are organic foods safer or healthier than conventional alternatives? A systematic review. Ann Intern Med. 2012;157(5):348-366.

4. Is organic food really more nutritious? Tufts University Health & Nutrition Letter website. http://www.tuftshealthletter.com/ShowArticle.aspx?rowId=368. September 2007. Accessed April 19, 2013.

5. Schardt D. Going organic: what’s the payoff? Center for Science in the Public Interest website. http://www.cspinet.org/nah/articles/going-organic.html. October 2012.

6. Brandt K, Leifert C, Sanderson R, Seal CJ. Agroecosystem management and nutritional quality of plant foods: the case of organic fruits and vegetables. Crit Rev Plant Sci. 2011;30(1-2):177-197.       

7. What is organic? United States Department of Agriculture website. http://www.ams.usda.gov/AMSv1.0/nop. Updated May 3, 2013. Accessed April 18, 2013.

8. Organic standards. United States Department of Agriculture website. http://www.ams.usda.gov/AMSv1.0/ams.fetchTemplateData.do?template=Template
. Updated April 4, 2013. Accessed April 18, 2013.

9. Global trends in healthy eating. Nielsen website. http://www.nielsen.com/us/en/newswire/2010/global-trends-in-healthy-eating.html. Updated August 30, 2010. Accessed April 21, 2013.

10. USDA National Organic Program, USDA Science and Technology Programs. 2010-2011 Pilot Study: Pesticide Residue Testing of Organic Produce. United States Department of Agriculture website. http://www.ams.usda.gov/AMSv1.0/getfile?dDocName=STELPRDC5101234. November 2012.

11. Curl CL, Fenske RA, Elgethun K. Organophosphorus pesticide exposure of urban and suburban preschool children with organic and conventional diets. Environ Health Perspect. 2003;111(3):377-382.

12. Parker-Pope T. Pesticide exposure in womb affects IQ. The New York Times website. http://well.blogs.nytimes.com/2011/04/21/pesticide-exposure-in-womb-affects-i-q. April 21, 2011. Accessed April 23, 2013.

13. Record-high antibiotic sales for meat and poultry production. The Pew Charitable Trusts website. http://www.pewhealth.org/other-resource/record-high-antibiotic-sales-
. February 6, 2013.

14. National Antimicrobial Resistance Monitoring System. 2011 retail meat report. US Food and Drug Administration website. http://www.fda.gov/downloads/AnimalVeterinary/SafetyHealth/AntimicrobialResistance/

15. Cephalosporin order of prohibition goes into effect. US Food and Drug Administration website. http://www.fda.gov/AnimalVeterinary/NewsEvents/CVMUpdates/ucm299054.htm. April 6, 2012.

16. Industry statistics and projected growth. Organic Trade Association website. http://www.ota.com/organic/mt/business.html. June 2011. Accessed April 18, 2013.

17. 10 reasons organic food is so expensive. FOX News website. http://www.foxnews.com/leisure/2012/03/11/10-reasons-organic-food-is-so-expensive/ - ixzz2RbCdXLXr. March 11, 2012. Accessed April 23, 2013.

18. EWG’s 2013 shopper’s guide to pesticides in produce. Environmental Working Group website. http://www.ewg.org/foodnews/summary.php. Accessed April 22, 2013.

19. Pesticide Q & A. US Food and Drug Administration website. http://www.fda.gov/Food/FoodborneIllnessContaminants/Pesticides/ucm114958.htm. Updated February 20, 2013. Accessed April 23, 2013.

20. Buying organic is easier and more affordable than ever before. Organic: It’s Worth It website. http://www.organicitsworthit.org/get/buying-organic-easier-and-more-affordable-

21. Forman J, Silverstein J; Committee on Nutrition; Council on Environmental Health; American Academy of Pediatrics. Organic foods: health and environmental advantages and disadvantages. Pediatrics. 2012;130(5):e1406-e1415.


Table 1: Produce With the Most and Least Pesticides18

Dirty Dozen

Clean 15

Cherry tomatoes
Hot peppers
Nectarines (imported)
Sweet bell peppers

*According to the Environmental Working Group, kale/collard greens and summer squash “do not meet traditional Dirty Dozen criteria but were commonly contaminated with pesticides exceptionally toxic to the nervous system.”


Sweet corn
Sweet peas (frozen)
Sweet potatoes