|Organic Verses Conventional
Is organic food more nutritious than conventionally grown food?
USDA does not claim that organic foods are safer or more nutritious than those produced conventionally (Mayo
Clinic, 2008). Yet, many people who produce, purchase and eat organic foods feel they are safer than, have
higher nutritional quality than, and taste superior to conventionally grown food. Others purchase organic foods for
environmental reasons, contending that organically grown foods reduce the negative impact on the environment
(Bourn & Prescott, 2002).
Little research has been done on the pesticide residue content of organic versus conventional foods. Therefore,
it is difficult to make a definite conclusion. Yet, due to the committed avoidance of synthetic chemicals as
pesticides on certified organic crops and the documented residue concentrations in conventional foods, it is
highly likely that certified organically grown food contains less residue levels than conventionally grown foods
(Bourn and Prescott, 2002).
In the scientific community there is increased concern over the adverse effects of ingestion of small doses of
pesticides and other chemicals, especially among vulnerable populations such as pregnant women and infants
(Environmental Working Group, 2008). Because the consequences of pesticide exposure are troublesome, not
well understood, or in a few cases not yet researched, experts recommend that individuals try to minimize their
exposure to pesticides as much as possible. According to the Environmental Working Group (EWG), a research
and advocacy organization in Washington, DC, individuals can greatly reduce their exposure to pesticides by
avoiding the 12 most contaminated fruits and vegetables and purchasing their organically-grown counterparts.
Because 51,000 tests on crops conducted by the U.S. Department of Agriculture and the U.S. Drug
Administration between 2000 and 2005 (EWG, 2008) showed the highest levels of pesticides in these fruits and
vegetables: peaches, apples, sweet bell peppers, celery, nectarines, strawberries, cherries, lettuce, grapes
(imported), pears, spinach, and potatoes, it may be worthwhile for the consumer to consider purchasing the
Individuals may also decide to purchase organic foods because they believe them to be more nutritious than
conventionally grown foods. Numerous studies have attempted to compare the nutrient compositions of
organically- and conventionally-grown foods. However, results are confounding because there are so many
factors that can affect the nutritive composition of crops (Bourne & Prescott, 2002). Just a sampling of influences
on crop nutritive value include the type of crop and plant species; soil type and composition; climate such as light,
temperature, rainfall, and humidity; microorganisms present in soil; management practices such as crop rotation,
pesticide use, and irrigation; harvest time or crop maturity; handling and storage; and, processing techniques and
conditions (Bourn & Prescott, 2002).
Research has shown that species variety and geographical variations such as soil composition, type of fertilizer,
and climate are of equal or of more importance when determining the nutritive quality of foods than whether the
crop is grown organically or conventionally (Worthington, 1998). For instance, the results from studies comparing
the vitamin C levels of different fruits and vegetables grown organically and conventionally are inconsistent (Bourn
and Prescott 2002; Magkos, Arvaniti & Zampelas, 2003). The variation in results can be partially explained
because vitamin C content is easily affected by maturity at harvest, storage conditions such as temperature and
humidity, surface bruises, and presence of oxygen. This is also true for other nutrients such as beta-carotene,
iron and manganese, whose nutritive value in foods are not only affected by farming techniques (organic vs.
conventional) but are also influenced by various other factors (e.g. soil and fertilizer type, maturity at harvest,
climate, crop variety and species, handling, processing and storage) that either cannot be controlled or are more
difficult to control.
Of interest is also the phytonutrient composition of organically and conventionally grown crops. Phytonutrients are
substances that plants produce naturally to protect themselves and provide the plant’s color, aroma, texture, and
flavor. Most fruits and vegetables contain phytonutrients, and this chemical family has demonstrated nutritive
health benefits. For instance, lutein, which is present in green vegetables such as kale, spinach, and broccoli,
may aid in maintaining healthy vision. One finding that appears to be consistent among studies is that organic
foods tend to have lower levels of nitrates, which is a nitrogen-containing compound. Research has
demonstrated that greater applications of nitrogen (in commercial fertilizer) may reduce the phytonutrient
composition in crops. Thus, some organically grown crops may have greater levels of phytonutrients than the
same crop grown conventionally in the same area (Bourne & Prescott, 2002).
Due to mixed results from research studies and the various factors that affect the nutritional quality of grains, fruits
and vegetables, there is no simple answer for the consumer asking “Is organic produce healthier than
conventional produce?” Additional research is needed to explore the myriad variables that can affect the nutritive
value of produce. However, whether you purchase organically or conventionally grown foods, it is well
documented that a diet providing a wide variety of whole grains, fruits and vegetables has immediate health
Katie Jeffrey-Lunn, MS, RD, CD-N, LD-N, is the owner of FitNutrition, LLC, in Mystic. For more information, call
860-536-3610 or go online to www.fitnutrition.net.
Bourne, D. & Prescott, J. (2002). A comparison of the nutritional value, sensory qualities, and food safety of
organically and conventionally produced foods. Critical Reviews in Food Science and Nutrition. 42(1):1-34.
Environmental Working Group. Shopper’s Guide. Retrieved July 1, 2008 from http://www.foodnews.org/.
Magkos, F., Arvaniti, F., & Zampelas, A. (2003). Organic food: nutritious food or food for thought? A review of the
Mayo Clinic Staff. (2006). Organic foods: Are they safer? More nutritious? Retrieved July 1, 2008 from http://www.
Worthington, V. (1998). Effect of agricultural methods on nutritional quality: a comparison of organic with
conventional crops. Altern Ther Health med. 4(1):58-69.
First appeared in The Stonington Times and The Mystic Times on June 26, 2008