By Kerri-Ann Jennings , June 19, 2012 - 12:22pm
Today, the nonprofit Environmental Working Group (EWG) released its latest report, called the Dirty Dozen, of the 12 fruits and vegetables that contain the most pesticides (see below). It also put out the Clean 15, a list of the least contaminated produce. The EWG updates this report based on the most recent USDA and FDA data on how much pesticide residue is found on conventionally grown crops.
If these lists leave you wondering just how bad pesticides actually are for your health and whether organic produce truly is worth the extra money it often costs, read on.
There are at least two good health arguments for eating organic: fewer pesticides and more nutrients . Let’s start with pesticides. Pesticides can be absorbed into fruits and vegetables, and leave trace residues. As Melinda Wenner Moyer reported on for EatingWell Magazine, there are hundreds of pesticides approved for use in the United States and they all present different risks: some are linked with cancer, while others can cause birth defects or harm the nervous system. Some pesticides—including organophosphates commonly used on crops—are what are known as endocrine disruptors, which means that they affect the body’s highly sensitive endocrine (hormone) system. There’s good reason to be concerned about this: the body uses hormones to coordinate just about everything—cell growth, appetite and metabolism, among other things. (Organophosphates, despite the name, are synthetic pesticides linked with neurological problems, among other health conditions.)
Some experts argue that we shouldn’t worry so much about pesticide residues. The Centers for Disease Control’s 2009 National Report on Human Exposure to Environmental Chemicals found that most people had organochlorine pesticides (commonly used to protect crops from insects) in their bodies, but the levels detected were too low for concern. However, other researchers from the University of Texas School of Public Health state that even if exposure to individual pesticides is low, consuming mixtures of these chemicals may cause health problems.
In a 2011 University of California, Berkeley study published in Environmental Health Perspectives, pregnant women who had high levels of organophosphate pesticides had children who scored lower on IQ tests years later.
Don’t Miss: 8 Genetically Modified Foods You Should Pay Attention To 
From a nutrient perspective, there’s mixed research on whether organic produce is more nutritious. Case in point: a 2009 review published in the American Journal of Clinical Nutrition reported that there is no sufficient evidence of a difference in nutrient quality. But a 2007 study by Newcastle University in the United Kingdom found organic produce had 40 percent higher levels of some nutrients (including vitamin C, zinc and iron) and a 2003 study in the Journal of Agricultural and Food Chemistry found that organically grown berries and corn had 58 percent more polyphenols—compounds that give fruits and vegetables their disease-fighting benefits—and up to 52 percent higher levels of vitamin C than those conventionally grown.
Don’t Miss: 5 Myths About Organic Chicken and Meat, Busted 
Bottom line: If you’re worried about pesticides, using the Dirty Dozen and Clean 15 to guide your purchases is one way to limit your exposure. But remember that eating fruits and vegetables—conventional or not—is far more important to your health than avoiding them based on a fear of pesticides, so don’t get so hung up on organic that you eat less produce than you otherwise would. David Wallinga, M.D., director of food and health for the Institute for Agriculture and Trade Policy, says scientists believe that some pesticides wreak their damage by operating as free radicals, compounds that damage tissues in ways that can lead to the development of cancer and other diseases. Minimizing your exposure to pesticides will reduce this free-radical damage, of course, says Wallinga, but so will consuming more antioxidants, which mop up free radicals.
Must-Read: 10 Ways to Eat Clean 
EWG’s 2012 “Dirty Dozen Plus”*:
3. Sweet Bell Peppers
• Green Beans
*Editor’s Note: This year, the EWG added this new “Plus” category to the Dirty Dozen in order to highlight crops that “did not meet traditional Dirty Dozen criteria but were commonly contaminated with highly toxic organophosphate insecticides.”
EWG’s 2012 “Clean 15”
2. Sweet Corn
6. Sweet Peas
12. Sweet Potatoes
How do you decide which foods to buy organic and which foods to buy conventional? Tell us what you think below.