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To eat or not to eat…organic?

Pick just about any newspaper or journal and during the course of a year, one or more articles will be devoted to the benefits or not of organic foods and the downsides or not of food grown with pesticides and herbicides.  These articles are often confusing. 

So how does one sort this out?

Organic food (or any food for that matter) is a combination of chemicals, most of which our bodies need in order to function well.   However, not all chemicals in food are useful to our body, and some of them are harmful at a certain level, like too much aflatoxin1 ---a natural fungal product---in peanut butter.  Organic food comes from plants grown without added pesticides, herbicides or genetic modifications. 2

Pesticides are usually human-made chemicals added to growing plants and sometimes even after the harvest to kill insects and other damaging animals, like rats.3   Herbicides are usually human-made chemicals that are added to soil or growing plants to kill weeds and fungi. 4  But did you know the plants we grow for food also produce pesticides and herbicides to protect themselves from insects and weeds?  Any gardener who has tried to grow tomatoes near a walnut tree can tell you this is true---the walnut tree’s roots produce a herbicide that is poisonous to tomato plants.4   The use of pesticides and herbicides, whether human-made or not, often results in small levels of these chemicals in our food.

Genetic modification of a food crop is one way to get the crop to naturally develop yet another pesticide and herbicide, or to give the crop a way to resist damage by a human-made herbicide.5 
So corn can be genetically modified to make a protein to protect it against insect damage and at the same time to resist damage by human-made herbicides used to kill weeks.  The use of genetically modified (GM) corn is popular because it increases yields, increases work efficiency by reducing the need for plowing, and protects soil by reducing erosion. 

So are these small levels of pesticides, herbicides and genetic modifications in our food harmful? 

Good question!  And one that scientists in many organizations try to answer on a daily basis.   In fact, the safety assessments for human-made pesticides and herbicides and genetic modification are well known.  Tens of millions of dollars are spent by competing industries on experimental animal and exposure studies.  These studies are reviewed by scientists in government and non-government organizations to establish safe levels of these compounds for humans and the environment.  A “safe level” means that the amount of a compound is less than the amount that would make a sensitive person sick.  As a result, no human-made pesticide, herbicide or genetically modified plant is used without knowing that the potential small level of these chemicals in our food is safe. 7 

So we can be sure that foods grown with human-made pesticides, herbicides and genetic modifications are as safe as to eat, or maybe safer, than organically grown food.  This is because human-made pesticides, herbicides and genetic modifications are extensively tested to determine safe levels, generally unlike the naturally occurring plant chemicals.   However, other issues about either method of growing food are important, such as farmer risk from exposures to human-made pesticides and herbicides, nutritional differences if any,8 or soil erosion from the extra plowing needed with organic farming. For more information, please consider visiting the websites listed in the footnotes.9


Michael L. Dourson, Ph.D., DABT, ATS
Board-Certified Toxicologist with the nonprofit organization Toxicology Excellence for Risk Assessment (TERA), dourson@tera.org

Douglas Lee, B.S.
Research Assistant with the nonprofit organization Toxicology Excellence for Risk Assessment (TERA), lee@tera.org

1. See also http://en.wikipedia.org/wiki/Aflatoxin. 

2. See also http://en.wikipedia.org/wiki/Organic farming; or http://www.usda.gov/wps/portal/usda/usdahome?navid=ORGANIC_CERTIFICATIO. 

3. See also http://en.wikipedia.org/wiki/Pesticide; or http://www.epa.gov/pesticides; or http://www.epa.gov/pesticides/kids/index.htm.

4. See also http://en.wikipedia.org/wiki/Herbicide.

5. See also http://www.ppdl.purdue.edu/ppdl/expert/black_walnut_toxicity.html. 

6. See also http://en.wikipedia.org/wiki/Genetically_modified_food; or http://www.ers.usda.gov/data-products/adoption-of-genetically-engineered-crops-in-the-us.aspx; or http://www.ornl.gov/sci/techresources/Human_Genome/elsi/gmfood.shtml.

7. See also http://www.who.int/foodsafety/publications/biotech/20questions/en/index.html; for a listing of safe levels for chemicals from different health organization around the world see http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?iter; for an essay on “Is it safe?,” click here.

9. Results were numerous for a Google query entitled “organic and conventionally grown foods, including GM foods.”  Many of these websites were judged by staff of Toxicology Excellence for Risk Assessment (TERA) as too biased, not credible, or non-related.  The following 3 websites were not biased, credible and related:





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