In every major grocery store chain in the United States one can find organic and conventional foods. It is no longer a category exclusively found in health food stores. The stated principles of organic agriculture are “health, ecology, fairness, and care” but if you ask people why they buy organic, the strongest predictor was concern for their own health or their family’s. People may spend more for organic more for selfish, rather than altruistic, motives. Although organic foods may not have more nutrients per dollar, consumption of organic foods may reduce exposure to pesticide residues and antibiotic-resistant bacteria.

Food safety-wise, they found no difference in the risk of contamination with food poisoning bacteria in general. Both organic and conventional animal products were commonly contaminated with Salmonella and Campylobacter, for example. Most chicken samples were found to be contaminated either way with Campylobacter, about a third with Salmonella but, the risk of exposure to multidrug-resistant bacteria–resistant to multiple classes of antibiotics–was lower with the organic meat. So they both may carry the same risk of making us sick, but food poisoning from organic meat may be easier for doctors to treat.

What about the pesticides? There is a large body of evidence on the relation between exposure to pesticides and elevated rate of chronic diseases such as different types of cancer, diabetes, neurodegenerative disorders like Parkinson’s, Alzheimer’s, and ALS, as well as birth defects and reproductive disorders, but they’re talking about people who live or work around pesticides.

Take Salinas Valley California, for example, where they spread half a million pounds of the stuff. Daring to be pregnant in an agricultural community like that may impair childhood brain development, such that pregnant women with the highest levels running through their bodies, as measured in their urine, gave birth to children with an average deficit of about seven IQ points. 26 out of 27 studies showed negative effects of pesticides on brain development in children. These included attention problems, developmental disorders, and short-term memory difficulties.

If you compare kids born with higher levels of a common insecticide in their umbilical cord blood, those who were exposed to higher levels are born with brain anomalies. And these were city kids, so presumably this was from residential pesticide use.

Residential exposure to pesticides, like using insecticides inside your house, may be a contributing risk factor for cancers like childhood leukemia, suggesting that awareness be increased among populations occupationally exposed to pesticides about their potential negative influence on the health of their children–though I don’t imagine most farmworkers have much of a choice. Pregnant farmworkers may be doubling the odds of their child getting leukemia and increase their risk of getting a brain tumor.

So conventional produce may be bad for the pregnant woman who picks them, but what about our own family when we eat them?

First of all, just because we spray pesticides on our food in the fields doesn’t mean it ends up in our bodies when we eat it–or at least we didn’t know that until this study was published in 2006. Researchers measured the levels of two pesticides running through children’s bodies by measuring specific pesticide breakdown products in their urine. Here are the levels of pesticides flowing through the bodies of 3- to 11-year olds during a few days on a conventional diet. Then they went on an organic diet for five days, and then back to the conventional diet. It’s clear that eating organic provides a dramatic and immediate protective effect against exposures to pesticides commonly used in agricultural production. The study was subsequently extended. Can you guess when the kids were eating organic? You don’t even need the labels on the graph to tell (see video). What about adults, though? We didn’t know, until now. Thirteen men and women consume a diet of at least 80% organic or conventional food for seven days, and then switched. And no surprise, during the mostly organic week, pesticide exposure was significantly reduced, and not just by a little: a nearly 90% drop in exposure.

So it can be concluded that consumption of organic foods provides protection against pesticides, but does that mean protection against disease? We don’t know—the studies just haven’t been done. Nevertheless, in the meantime, the consumption of organic food provides a logical precautionary approach.

Whether you consume organic fruits and vegetables or commercial ones, you should wash them prior to eating them. Next week, I’ll show you How to make your own fruit and vegetable wash. For more information be sure to check out my latest videos including this one Are Organic Foods Safer? on NutritionFacts.org

In health,

Michael

Dr. Greger is a graduate of Cornell University School of Agriculture and Tufts University School of Medicine. He is also the founding member of the American College of Lifestyle Medicine. He is a physician, author and internationally recognized speaker on nutrition, food safety and public health issues. He has lectured at the Conference on World Affairs, testified before Congress, appeared on “The Dr. Oz Show” and “The Colbert Report,” and was an expert witness in the defense of Oprah Winfrey in the “meat defamation” trial. He is the author of the international bestseller “How Not To Die.” Currently, Dr. Greger serves on the advisory board for The Only Vegan At The Table and the North Texas Community Health Initiative. He is also the founder of NutritionFacts.org, a nutrition information website with hundreds of videos available for free. “Mondays With Michael” is a weekly column featuring the latest in science-based nutrition information.