Pick just about any newspaper or magazine, and during the course of a year it’s likely that one or more articles will be devoted to the benefits (or lack of benefits) of organic foods and the downsides (or lack of downsides) of “conventionally grown” food – food grown with synthetic pesticides and herbicides. These articles are often inconsistent, and paint a confusing picture.
So how does one sort this out?
Food, whether organically or conventionally grown, is a combination of chemicals, many 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, like too much aflatoxin 1 (a natural fungal product that can be found in peanut butter) are harmful at a certain level. Organic food comes from plants grown without added synthetic pesticides, herbicides or genetic modifications.2 ,3
Pesticides are usually human-made chemicals added to growing plants and sometimes to the crop after the harvest to kill insects and other damaging animals, like rats.4 Herbicides are usually human-made chemicals that are added to soil or growing plants to kill weeds and fungi.5 But did you know the plants we grow for food naturally produce pesticides and herbicides to protect themselves from insects and weeds?6 Any gardener who has tried to grow tomatoes near a walnut tree can tell you this is true—the walnut tree’s roots produce an herbicide that is poisonous to tomato plants.7 The use of pesticides and herbicides, whether human-made or natural, often results in small levels of these chemicals in our food.
So are these small levels of pesticides or herbicides in our food, whether human-made or natural, harmful?
Good question! And one that scientists in many organizations try to answer on a daily basis. In fact, regulatory agencies conduct extensive safety assessments for human-made pesticides and herbicides. Tens of millions of dollars are spent by companies to test for health effects of the pesticides and herbicides, and to estimate human exposure. 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 a level of a compound is less than the level that would make a sensitive person sick. As a result, no human-made pesticide or herbicide is used without knowing its safe level, and without determining that the potential small levels of these chemicals in our food are below the safe level.8
So we can expect that foods grown responsibly using
human-made pesticides, herbicides and genetic modifications are safe for people to eat. This is because human-made pesticides and herbicides are extensively tested to determine safe levels, generally unlike the naturally occurring plant chemicals.9
However, other issues about either method of growing food are important. For example, organically grown foods may better maintain a sustainable farm practice, may reduce unanticipated environmental impacts of a human-made pesticide or herbicide, and would reduce accidental and often demonstrated harmful worker exposures to these chemicals. Conversely, conventional farming reduces soil erosion when compared with organic farming, which generally requires extra plowing. And while eating organic foods has been demonstrated to lower consumer exposure to some human-made pesticides and herbicides,10 insect damage to unprotected plants can cause natural pesticides levels to increase. 11
Nutritional content of food grown by either method does not appear to differ.10,12
Michael L. Dourson, Ph.D., DABT, ATS
Board-Certified Toxicologist with the nonprofit organization Toxicology Excellence for Risk Assessment (TERA), firstname.lastname@example.org
Douglas Lee, B.S.
Research Assistant with the nonprofit organization Toxicology Excellence for Risk Assessment (TERA), email@example.com
Lynne Haber, Ph.D., DABT
Toxicology Excellence for Risk Assessment (TERA), firstname.lastname@example.org
Patricia Nance, M.Ed., M.A.
Toxicology Excellence for Risk Assessment (TERA), email@example.com
1. See also http://en.wikipedia.org/wiki/Aflatoxin.
2. Genetic modification of a food crop, whether done in the lab or naturally through conventional cross-breeding, is one way to get the crop to develop yet another pesticide and herbicide, or to give the crop a way to resist damage by a human-made herbicide.
3. See also http://en.wikipedia.org/wiki/Organic farming; or http://www.usda.gov/wps/portal/usda/usdahome?navid=ORGANIC_CERTIFICATIO.
8. See alsohttp://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.
11. Jason J. Hlywka , Gerald R. Stephenson , Mark K. Sears , Rickey Y. Yada. 1994.
Effects of insect damage on glycoalkaloid content in potatoes (Solanum tuberosum). J. Agric. Food Chem., 42 (11), pp 2545–2550.
13. 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 biased, not credible, or not relevant to the specific issue of food safety. In addition to the websites listed in the above footnotes, the following 3 websites were unbiased, credible and relevant: