Environmental Nutrition

The support for choosing "clean" foods, free of such chemicals as contained in pesticides, is broadening. According to the U.S. Department of Agriculture (USDA), organic food sales grew by more than 7 percent last year, partly driven by consumer concern about the use of pesticides in food production and their impacts on health and the environment.

What are pesticides? Pesticides act on biochemical targets to disrupt growth regulation and alter the life cycle of pests, including insects, weeds and fungi. But by design they also have the potential to disrupt the health of non-target species, like soil microorganisms, butterflies, bees, earthworms, wildlife and even humans.

How safe are pesticides?

To ensure food safety, the Federal Food and Drug Administration (FDA) and the USDA regulate pesticide residues, essentially any pesticide that remains in or on food or feed, and the Environmental Protection Agency (EPA) establishes maximum residue levels (tolerances) when registering a pesticide. In setting the tolerance, the EPA must make a safety finding that the pesticide can be used with "reasonable certainty of no harm." To make this finding, EPA examines evidence provided by the company on the toxicity of the pesticide, its break-down products, how much is applied and how often, and how much remains in or on food by the time it is marketed. According to the FDA's pesticide residue monitoring program, levels of pesticide residues in the US food supply continue to be well below established safety standards.

But even though there are safety mechanisms in place, concerns still exist. The EPA has been criticized for its weak data management and overuse of a loophole called "conditional registration," which allows pesticides to be sold before all safety studies are complete. In 2013, an internal review by the Government Accountability Office determined that the EPA had 16,156 active pesticide registrations and that 69 percent of these pesticides were "conditionally registered."

Studying the effects of pesticides on health is difficult. Studies rarely consider how pesticides accumulate in the body, or how multiple pesticides react with each other. Safety studies are based on the effects of single chemicals, but foods typically contain more than one chemical. The FDA's Total Diet Study, an ongoing FDA program that determines levels of 5,000 toxic elements and chemical contaminants in 280 commonly consumed foods, found traces of multiple pesticides in many commonly consumed foods.

Emerging research shows that even very low doses of chemicals, such as endocrine disruptors which may act similar to hormones in humans and animals, may have strong effects, according to a 2007 review in Environmental Health News. Although we need more studies to understand the definitive effects of pesticides, research has shown a wide range of potential harmful effects on humans, according to the global advocacy organization Pesticide Action Network, including brain and nervous system impacts, cancers, sexual and reproductive dysfunctions, birth defects, learning and developmental disruption, metabolic effects (i.e., obesity, diabetes), immune disorders, asthma and Parkinson's disease.

Who's at risk for exposure?

A report from the Centers for Disease Control and Prevention found that more than 90 percent of U.S. residents carry a mixture of pesticides in their bodies , a number that is higher among agricultural farm workers. Further, children, pregnant or nursing women, the elderly and the immune-compromised may be more at risk to the effects of pesticides.

Reducing Pesticide Exposure

In order to reduce your exposure to pesticides, here are a few steps you can follow.

--Buy organic. Eating certified organic produce decreases the number of pesticides you are exposed to, because the National Organic Program bans the use of synthetic pesticides in organic production, though "organic" pesticides, such as some alcohols, some chlorine materials, coppers and botanical oils are allowed.

--Focus on foods. The Environmental Working Group (EWG) publishes an annual report of tested produce with the highest and lowest pesticide loads called the Dirty Dozen and the Clean Fifteen (see sidebar). Though the health benefits of a diet rich in produce outweigh the risk of pesticide exposure, these produce guides are useful in determining what types of organic vs. regular produce you should buy.

--Know your farmer. If you shop at a farmers market, ask your farmer questions about their pest control methods. They may not be certified organic, but many employ pesticide-free practices.

--Rinse, scrub, peel. Rinsing, scrubbing and peeling your produce before eating can help reduce pesticides. However, some are "systemic," meaning they are taken up by the plant's roots and distributed throughout the plant, and washing will not remove them.

--Trim fat. Because many chemicals, such as pesticides, accumulate in fatty tissue, trimming fat from your meat and poultry can help reduce exposure.

--Grow your own. Gardening allows you to control the application of pesticides.

The Dirty Dozen Plus