Spring 2008: Of Note

Chensheng Lu tossing a peach in the air

Not so peachy: Switching from conventional to organic foods can immediately lower pesticide exposure.

Kay Hinton

Poison Apples

Public health researcher Chensheng Lu finds that pesticides linger in children

By Paige P. Parvin 96G

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Walk into any major grocery store and you’ll find a produce section bursting with nature’s bounty: brightly colored rows of fruits and vegetables temptingly arrayed to help hurried shoppers reach for the “five a day” target health experts are always advocating.

But that colorful produce may carry toxins we can’t see. A new study led by Chensheng Lu, assistant professor of environmental and occupational health at the Rollins School of Public Health, found that the urine of children who ate conventionally grown, nonorganic foods contained traces of organophosphate pesticides, a type of neurotoxin related to nerve gas. The chemical kills insects by interfering with their nervous systems; in humans, it can block a key enzyme and prevent the nervous system from functioning properly.

Foods with the highest pesticide levels

1. Peaches

2. Apples

3. Sweet bell peppers

4. Celery

5. Nectarines

6. Strawberries

7. Cherries

8. Lettuce

9. Grapes (imported)

10. Pears

Source: The Environmental Working Group

Lu and his colleagues monitored twenty-three preschool and elementary school children in Mercer Island, Washington, on their regular family diets during the course of a year. In the summer and fall, the researchers provided the children with an all-organic diet for five consecutive days.

The change was dramatic, Lu says. During the five days on the organic diet, there were no signs of pesticides in the children’s urine.

Unlike other types of pesticides such as DDT, organophosphates have a relatively short half-life, Lu explains, which is why he needed to monitor the children daily to measure their exposure. Because the pesticide degrades quickly, he did not expect such a conclusive result.

“What really surprised us is that the outcome reflects the hypothesis that by switching to organic produce, there would be no exposure to pesticides,” he says. “The study proved that this type of pesticide is only transmitted through diet.”

During the winter and spring, Lu anticipated that the level of pesticide exposure would decrease because fewer fresh vegetables and fruits are available. Instead, however, he found that it increased or even rose slightly. Lu realized that at least some of this exposure came from imported produce.

These findings come on the heels of the tenth anniversary of Congress’s Food Quality Protection Act, a measure that required a comprehensive reevaluation of the use of pesticides. The decade-long process has resulted in a significant decrease in pesticides, but Lu believes the risks remain unclear.

“This is part of the deficiency of the research,” he says. “We don’t really have a clear idea of whether there would be adverse health effects based on this low level of exposure.”

Lu is repeating the study, which was published earlier this year in Environmental Health Perspectives, with children in Atlanta and plans to continue to explore the effects of the pesticides. He also wants to find out how many parents of the children studied opt to change their diets due to the results.

The father of two boys, Lu says about 70 percent of his family’s diet is organic food. They base these choices on a study by the Environmental Working Group that tested conventional fruits and vegetables and ranked them based on their pesticide level. Unfortunately for the Peach State, peaches rank first. But Lu points out that grocery stores are offering an increasing range of organic choices.

“The issue now is there is very little increase on the supply side,” he says. “But in three to five years, there will be a substantial amount of organic stuff on the market, and hopefully prices will drop so it will be more affordable.”

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Spring 2008

Of Note

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