Boise State Researcher Could Change How We Study Pesticides

Feb 5, 2015

A Boise State University professor wants to make it easier to decide whether it's worth it to spend a little more on organic produce, or purchase the cheaper non-organic option.

"Eighty percent of American grocery stores now sell organic food and people have to decide for themselves is this worth it to buy to feed myself and my family?" says Cynthia Curl. "We don't have a lot of guidance to give to those people and so I think it's a really important thing to study."

Curl has found a new way to predict how much pesticide produce is putting in your body, without a lot of complicated, and pricey, tests.

Before Curl joined BSU's Department of Community and Environmental Health, she was at the University of Washington. There, she studied a group of 4,500 people. She was looking for a cheaper way for researchers to predict how much organophosphate, a common insecticide in the U.S., is left behind on the fruits and vegetables we eat. 

Researchers have to rely on biological markers, like urine tests, to figure out how much organophosphate is in the human body. "But a urine sample only represents what you ate over the last day or so," says Curl, "so maybe you sometimes eat organic, but you didn't happen to yesterday. That urine sample is really just a snapshot of your exposure."

Curl wanted to use a dietary questionnaire to estimate people's pesticide residue levels. "We hope that by having people report on their typical diets, we actually do a better job of estimating their chronic exposure."

So she looked at the average pesticide residue levels left on foods, like apples and pears. That information is checked by the USDA. Then, she asked her study group what they were eating. Apples? Pears? Organic? She combined that information to accurately predict people's exposure to pesticides.

"This should allow us in future studies to collect questionnaire information and use that to predict exposure," she says, "and then work towards understanding that exposure and health effects." That's important, Curl says, because "we'll be able to do that less expensively, less invasively, and in larger populations."

Her study didn't look at the health effects of pesticides on the human body, that will come in later research, which should be easier to complete, thanks to her new prediction model. But her study did find people who ate organic fruits and vegetables had less organophosphate in their bodies. She says that's not new information, other studies have found that to be true. It's the way she got results, without biological markers, that could have significant implications for future research. 

Curl says if you're worried about pesticide exposure, there are ways to find the best, and worst, foods to eat. She recommends checking out the "Dirty Dozen" list, from the Environmental Working Group.

Fruits and veggies that have more pesticide residue include:

  1. Apples
  2. Strawberries
  3. Grapes
  4. Celery
  5. Peaches
  6. Spinach
  7. Sweet bell peppers
  8. Imported nectarines
  9. Cucumbers
  10. Cherry tomatoes
  11. Imported snap peas
  12. Potatoes

Curl says in the end, studies like hers boil down to offering consumers options.

"Organic food gives people an option to reduce their pesticide exposure and until we have a better understanding of what the health effects of low-level exposure to pesticides may be, it's important for people to feel like they have a choice."

Curl's research is being published Thursday in the journal Environmental Health Perspectives.

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