Proving the Organic Benefit:
Comparing Apples to Apples

By Charles M. Benbrokk, Ph.D.


Comparing apples to apples might seem pretty straightforward but for the organic industry, this task raises complex scientific and communication challenges. Up to now, the lack of well-designed scientific studies has made it difficult to answer a basic question, “Do organic products offer consumers proven health and environmental benefits over conventional food products?”

There are many reasons why organic processors and producers should support efforts to rigorously compare the nutritional, food safety, and health-promoting attributes of organic apples, peaches, celery and other foods with their conventional counterparts. More research is needed to better understand the contributions that antioxidants and other beneficial secondary plant metabolites–which are generally higher in organic produce–can make to healthy development and aging. Likewise, more research is vital to quantify the degree to which growing and consuming organic food can improve reproductive outcomes and promote healthy infant and childhood development, while also minimizing the risks faced by farmers and farm workers. Last, if there are food safety risks unique to organic food production and processing, it is our responsibility to gain the knowledge needed to eliminate them through rigorous monitoring and careful management.

Research also is needed to establish the science base that the U.S. Food and Drug Administration (FDA) needs prior to approval of novel health claims associated with the consumption of organic food. The fact is that although consumers may initially perceive organic products as more healthful, safer or better for the environment, that perception could be eroded if the industry cannot quantify the benefits of organic food and farming systems using methods and data widely accepted by the scientific community.

Founded in 2002, the Organic Center for Education and Promotion (The Organic Center), is a non-profit organization that helps consumers, policy makers, researchers and the media understand the benefits that organic farming and food provides to both individuals and society. The Organic Center aims to sponsor and highlight credible, peer-reviewed scientific research about the organic benefit. By doing so, we will promote consumer awareness of the organic benefit, accelerate the conversion of more farmland to organic systems, improve public health and soil and water quality, and promote biodiversity within healthier rural communities. In its role as a clearinghouse for information, The Organic Center tracks research, both past and current, analyzes the result, and explains how the information helps document the nature and extent of the organic benefit. As a catalyst sponsoring new research, the Center works with leading scientists willing to carry out cutting-edge studies on aspects of the organic benefit that are high on the Center’s list of priority topics.

The Organic Center is blessed by the privilege to work with a strong group of scientists and industry leaders. The Center’s technical program is focused on completing a series of State of Science Reviews (SSRs). Each SSR will identify research required to develop improved methods to verify and quantify actual and potential benefits of organic foods. They will also address contemporary controversies, potential problems and food safety issues. Information needed to maximize organic benefits and minimize potential risks will be highlighted. Essentially, a SSR is designed to establish a baseline on what current science shows about the benefits of organic food to the people who eat it and to the environment, and to identify the scientific work needed to develop sharper, more compelling quantitative estimates of the quality premium associated with organic food.

Each SSR will include a focus statement on the importance of the topic to human health and/or the environment, the impacts of and linkages to organic food and farming systems, and a discussion of contemporary controversies and conflicting claims, if any. The content portion of the SSR provides an overview of existing methods and data used to study and quantify benefits of organic food and farming systems, identifies gaps in tools or data, and reviews experimental designs or analytical methods that offer promise in more solidly proving the existence of benefits or more accurately quantifying benefits. SSRs also contain an interpretive summary of existing studies assessing the impacts, performance and benefits of organic food and farming systems.

When possible, trends are discussed and benchmark studies are noted. Each SSR will highlight the relatively few studies in the literature that directly compare conventional with organic farming and food, as well as studies or government surveys that establish guidelines or benchmarks in nutritional quality, food safety or farming system performance that can be used in assessing the impacts of organic relative to conventional production systems and food.

Conclusions about the proven benefits of organic will be stated in the SSRs in as direct a way as possible, given current knowledge and evidence. These short, consumer-friendly “executive summaries” will hopefully prove useful to the industry as organic companies develop consumer education materials and deal with the media and others who have questions about the benefits of organic. SSRs will also strive to summarize conditional, potential or limited benefits, the circumstances in which a particular benefit is likely to arise, any proven or potential disadvantages or risks unique to organic food processing and production, and prospective new or expanded health claims.

With the recent publication of the first SSRs by The Organic Center, a core scientific foundation will be set in a couple of areas to guide further work. Over time, SSRs and the research they trigger will improve understanding of the organic benefit and our ability to communicate its dimensions and importance both to individuals and society.

Scientific Endeavors Bear Fruit
A growing body of epidemiological data links prenatal pesticide exposure, as well as exposures during the first years of a child’s life, to a variety of health issues including birth defects, abnormal neurological development, and reproductive problems. Nearly three-quarters of the fresh fruits and vegetables consumed most frequently by infants and children in the U.S. contain pesticide residues. People are exposed to pesticides in multiple ways throughout their daily lives. This is not surprising given the fact that there are approximately 600 pesticide-active ingredients and nearly 20,000 pesticide products in commerce in the U.S. In recent years, numerous scientific studies have shown that human exposure to pesticides, especially during key stages of development, increases the occurrence of chemical sensitivity, mental disorders, cancer and other health problems.

The Organic Center released in May 2004 key findings of a new health report examining the impact of pesticides on human health and the benefits of consuming certified organic foods. The report, Minimizing Pesticide Dietary Exposure Through Consumption of Organic Food, surveys and analyzes government data and scientific literature on the risks of pesticide exposure. The major finding of the second SSR, Impacts of Organic Food on Healthy Sexual Development and Reproduction, were discussed during a science update session at All Things Organic. The full SSRs with references, tables and appendices are available online at www.organic-center.org. This article will highlight some of the major findings of the first SSR.

Minimizing Pesticide Dietary Exposure Through Consumption of Organic Food assesses the extent to which consumption of organic food reduces pesticide dietary exposures. It begins by explaining why and how the June 1993 National Academy of Sciences report, Pesticides in the Diets of Infants and Children changed the scientific and regulatory debate on pesticides and food safety both domestically and internationally. This report formed the foundation for the passage of the Food Quality Protection Act (FQPA) in 1996 and led to greatly expanded government pesticide residue testing and pesticide dietary risk assessment research. This SSR also reviews the widely cited March 2003 study in the prestigious journal Environmental Health Perspectives entitled Organophosphorous Pesticide Exposure of Urban and Suburban Preschool Children with Organic and Conventional Diets. This remarkable study was carried out by Cynthia Curl and fellow researchers at the University of Washington. Children aged two- to five-years-old were divided into two groups, one group consuming a predominantly organic diet and the other consuming a predominantly conventional diet. The researchers measured the metabolites of organophosphate (OP) insecticides in the children’s urine and found an eight-fold difference in the mean levels.

There has been an explosion of new work on the mechanisms through which exposure to pesticides alters fetal and infant development. Other important science noted in the SSR include:

• A study published in March 2004 showing that the exposure to OP insecticides impairs the development of the brain in utero. Researchers have learned that during a few one- to two-day critical periods in fetal development, exposure to chlorpyrifos (the most widely used insecticide in America) can significantly affect the developing brain, setting the stage for life-long problems.

• In February 2004, researchers published another study in Environmental Health Perspectives that looked at farm worker exposure to pesticides. Scientists analyzed pesticide exposures and neurological outcomes across various agricultural tasks, documenting wide divergence in levels of exposure and impairment of basic nervous system functions, like coordination and problem solving ability.

The Center’s first published SSR stresses that in evaluating pesticide dietary risk in food, four factors must be taken into account and analyzed: The frequency with which the residues appear in a given food (i.e., the percent of the total number of samples that test positive); the number of residues that are found per sample; the levels of pesticides found in foods; and the toxicity of the pesticides present in foods. This SSR focuses on the first three factors and compares the frequency and levels of pesticide residues in conventional and organic foods by type of food, by year and by country of origin. The existing data sources used to assess and quantify differences included data from the USDA Agricultural Marketing Service (AMS)’s Pesticide Data Program (PDP). Annually since the early 1990s, the PDP has tested approximately 15,000 samples of a variety of fresh fruits and vegetables, about a half-dozen processed foods, and usually a few other foods like milk, rice or meats. The 1993-2002 PDP dataset contains the results from the testing of 14 organic and conventional vegetable crops. Some 63% of the 27,000 samples of conventional vegetables tested positive, while 18% of the 233 samples of organic vegetables were positive. Forty-four percent of 151 samples of vegetables labeled integrated pest management (IPM)-grown or “No Detectable Residues” (NDR) tested positive, significantly less than conventional and significantly more than organic.

The other significant data source used in this SSR is a detailed analysis of pesticide residue patterns published in 2002 in the peer-reviewed journal Food Additives and Contamin-ants (Baker et al.), which analyzed the distribution and levels of pesticides in conventional, IPM-NDR and organic foods from the late 1980s through 1999. The three datasets included six years of data from USDA’s Pesticide Data Program, 1993-1999; 10 years of data from the California Department of Pesticide Regulation (DPR), 1989-1998; and results from a 1998 Consumers Union (CU) report focusing on four crops (apples, peaches, tomatoes and peppers).

The pesticide residue data analyzed in the SSR supports several significant findings, including but not limited to:

• For most of the major fruits, a very high percentage of the samples contained residues. Data collected for the year 2002 showed that 95% of the apples, nectarines, peaches, pears and strawberries sampled have one or more residues.

• Over all PDP years, 18% of organic samples contained residues compared with 69% of no market claim produce. Figure 1 compares the frequency of residues in organic, organic-labeled produce, pesticide-free or NDR labeled produce, and produce with no market claim (conventional produce) using datasets from the PDP for all years and the 2002 PDP.

• Conventional food contains 4.3 times the pesticide residues in terms of frequency compared to organic.

• Soft-skin fruits are sometimes heavily contaminated with pesticides. Our study shows 551 out of 562 peach samples and 338 of 344 nectarines tested positive.

• Vegetables tend to be somewhat less contaminated than fruits. The conventional-to-organic ratio is 3.8-fold in the case of vegetables over the last three years.

• When reviewing datasets measuring the number of samples testing positive for multiple residues, the difference between organic and conventional becomes even more dramatic. Table 1 compares the number of samples containing multiple residues by market claim in three datasets—PDP, CU, and DPR. The important item to note is that the difference between organic and conventional food in terms of multiple residues in each of these three datasets is similar, on the order of ten-fold or more.

• About 45% of conventional fruit and vegetable samples contain residues from two or more pesticides. The average conventional apple tested in the PDP from 1994-1999 contained residues of three different pesticides. USDA tested 530 apple samples in 1996 and found that the odds of buying a five-pound bag of apples with nine or more different pesticide residues was as great as selecting a bag with no residues. This indicates that those who follow USDA’s dietary guidelines—consuming at least “five-a-day” servings of fruit and vegetables—are ingesting six or more pesticides on most days.

• In the supermarket, peach-buying consumers are 11 times more likely to pick a bag of peaches that will have seven or more residues than one with no residues. Conventional peaches and celery stand out as the most heavily pesticide-contaminated foods, with the average peach sample containing 4.25 residues and the average positive celery sample with 3.7 residues. Consumers are just as likely to select a stalk of celery containing five or more residues as celery with one or zero residues.

• In general, the pesticide residues found in imported organic produce raise more significant risk concerns than the residues found in U.S.-grown organic samples. On average, the residues that have been found in USDA testing of imported organic samples pose relative risks about six times greater than the residues found in domestic organic samples.

With the implementation of the National Organic Program (NOP) as of Oct. 21, 2002, all imported produce must meet the requirements of the NOP in order to be sold as organic in the U.S. Certifying organizations may need to more aggressively assess pest management systems and pesticide use by organic farmers abroad. If substantial differences in the frequency and levels of pesticides in imported versus domestic organic produce continue, USDA will need to focus more attention on pest management and pesticide use-related certification procedures in the accreditation process.

The conventional fruits and vegetables most heavily contaminated with pesticides include some frequently consumed by infants and children: apples, celery, pears, spinach, peaches, sweet bell peppers, nectarines, strawberries and cherries. Multiple pesticide residues are commonly found in these nine fruits and vegetables. Samples with no residues are uncommon, and in some cases, rare. This is a key finding that leads directly to a message for moms and dads with young children: The pesticide risk reduction benefits of seeking out and consuming certified organic apples, pears, peaches, strawberries, cherries, celery, spinach and sweet bell peppers are significant.

These are among the facts highlighted in the full SSR report (available free at www.organic-center.org). The full review also presents information on a new method developed to help answer the difficult question, “How risky is a pesticide residue?”

Core Perspectives and Conclusions
The SSR also addresses three claims that reflect different views on the public health benefits stemming from reducing pesticide exposures through consumption of organic food.


“Claim 1. Because organic farmers are not supposed to spray their crops with synthetic pesticides, the presence of residues in some samples of organic food must mean that a portion of organic farmers are not following the rules.”

This argument indirectly questions the integrity of organic farmers and certifiers, and suggests that consumers who seek out and pay more for organic food to avoid pesticides are not getting their money’s worth. The SSR counters this claim by discussing the various modes by which pesticides can be carried onto organic crops and foods.

“Claim 2. Natural pesticides approved for use on organic farms may actually pose dietary risks comparable to the synthetic pesticides used on conventional food.”

The NOP has approved a number of pesticides containing natural ingredients for use by certified organic farmers (e.g., sulfur, oils, soaps, copper-based fungicides, botanical insecticides, insect pheromones, and the microbial insecticide Bacillus thuringiensis). Residues of some of these natural substances, particularly sulfur, are common on fruits and vegetables, whether produced on an organic or conventional farm. The SSR notes that given the lack of testing for natural pesticides, there is no way to definitively disprove the claim that natural pesticide residues in organic food are as hazardous to people as the synthetic chemical residues in conventional food. For the same reason, there is no evidence in support of the claim and indeed, there is much evidence that strongly suggests it is groundless.

“Claim 3. Pesticide residues found in conventional food pose essentially no risk, so it should not matter to consumers that organic food contains relatively fewer residues.”

As stressed throughout the SSR, the degree to which organic food reduces pesticide dietary risks compared to conventional food is a function of the frequency of residues in food, the number of residues in a given sample of food, the average levels of residues present in food, and the relative toxicity of pesticides found in conventional and organic food. The SSR provides information on the extensive data that are available to quantify most of these differences. For vulnerable population groups, especially infants and children, the differences are significant and promise to deliver measurable public health benefits.

Minimizing Pesticide Dietary Exposure Through Consumption of Organic Food concludes that eating organically grown and processed foods, especially fruits and vegetables, significantly decreases the frequency and level of dietary exposure to pesticides, thus reducing the magnitude of one risk factor that can contribute to a variety of health problems. Public and private sector efforts to substantially increase fresh fruit and vegetable consumption are definitely among the best investments possible to improve public health in America. Reducing the frequency and levels of pesticides in food will build consumer confidence in the safety of fresh produce and is a solid step in the right direction in promoting healthier dietary consumption patterns. Further, the current state of science shows that eating organic foods can support healthy development in young children and lower the frequency of some health and reproductive problems that strike later in life. Because such a small number of foods account for most pesticide dietary exposure, selecting organic produce can provide a significant public health benefit.

In addition to this just-released SSR, The Organic Center for Education and Promotion recognizes the important need for substantial new research on the health promoting benefits of organic food and farming systems. Nutrition research in the past has been far too reductionist and has focused primarily on intake levels and patterns and macronutrients and vitamins, despite recognition that many other components of food impact health outcomes. It is time for the organic community to encourage scientists to dig deeper in identifying and understanding the constituents and characteristics of food that give rise to good health. We are hopeful that The Organic Center’s work over the next several years will serve as a catalyst for such work, while also making it easier for the organic industry to help the consumer understand that sometimes two apples can in fact be as different as apples and oranges.

Charles M. Benbrook, Ph.D., authored the report Minimizing Pesticide Dietary Exposure Through Consumption of Organic Food. Benbrook works on pest management, pesticide risk assessment, and sustainable agriculture strategies and policies. He is a consultant to The Organic Center for Education and Promotion. Benbrook worked in Washington, D.C., on agricultural policy, science and regulatory issues from 1979 through 1997, with roles as the agricultural staff expert on the Council for Environmental Quality; Staff Director of a Congressional subcommittee; and Executive Director of the Board on Agriculture of the National Academy of Sciences. Benbrook is an agricultural economist with a B.A. from Harvard University and a Ph.D. from the University of Wisconsin. He can be reached at cbenbrook@organic-center.org.