By Carolyn Butler
Tuesday, June 1, 2010; HE01
If you've been in a supermarket lately you've seen my type: roaming the produce aisles in a daze, silently debating organic or conventionally grown, local or imported, while weighing taste and health benefits against the often exorbitant price differential. And after all that, I usually end up deciding that eating more fruits and vegetables of any sort is the most important thing, no matter how they're grown or where they come from.
Now comes new research that is causing me to rethink my position and wonder whether I should be concentrating on limiting my family's exposure to the pesticides often found in trace amounts on commercially grown produce. What got me going is a study in last month's edition of the journal Pediatrics suggesting that even low levels of these chemicals are associated with an increased risk of attention-deficit hyperactivity disorder in children.
Researchers at the University of Montreal and Harvard University looked for organophosphate pesticide metabolites, an indicator of pesticide exposure, in the urine of 1,139 kids ages 8 to 15 and found that close to 95 percent had at least one of these chemical byproducts in their system. Those with the highest levels were 93 percent more likely to have received an ADHD diagnosis than children with none in their system. Those with above-average levels of the most common organophosphate byproduct -- they made up a third of the whole group -- were more than twice as likely as the rest to have ADHD.
"This is not a small effect," says study co-author Maryse Bouchard, a researcher in the University of Montreal's environmental and occupational health department, "and it is certainly cause for concern." She adds that while prior research has proved that high levels of organophosphate exposure can have negative impacts on children's behavior and cognitive function, in this study "we are talking about very low levels of exposure . . . levels that were believed previously to be safe and harmless but which are now associated with a serious health risk." She points out that most pesticide exposure today comes through food, particularly conventional fruits and vegetables.
Bouchard and other experts caution that the new findings, while suggestive, should not be considered definitive. "I wouldn't go before a group of parents today and say, 'Look, if you don't want your child to have ADHD, you should be concerned about pesticides,' " says Lynn Goldman, a pediatrician and professor at Johns Hopkins Bloomberg School of Public Health, who considers Bouchard's study well done. "We certainly don't want fear to cut fruit and vegetable consumption. But I do think this is well worth evaluation in other populations, over a longer period of time."
If you're concerned, there is a wealth of information establishing just how many chemicals we consume, starting with the Department of Agriculture's Pesticide Data Program, which tests thousands of food samples a year, tracking specific residue levels. According to its most recent report in 2008, for example, a type of organophosphate called malathion was detected in 28 percent of frozen blueberries, 25 percent of fresh strawberries and 19 percent of celery. "It's easy to have a dozen exposures [to different pesticides] in the course of a day," says Richard Wiles, senior vice president for policy at the Environmental Working Group, a Washington-based environmental advocacy group .
Still, we're doing better than before in reducing pesticide dangers in food, says Charles Benbrook, chief scientist for the Organic Center, a Colorado-based organic advocacy and research group. The center has a "dietary risk index," which takes into account how often pesticides are found in particular foods, at what levels, and just how toxic they are. "The good news is that in a lot of important fruit and vegetable crops, the dietary risk levels for domestically grown food have, in fact, gone down -- in some cases significantly, like with grapes and peaches -- since the passage of the Food Quality Protection Act in 1996," Benbrook says. Among other things, that law restricted the use of many dangerous chemicals in U.S. agriculture.
In fact, while the Environmental Protection Agency responded to the ADHD study by noting in a statement that it takes the research "very seriously," it also said that since the study's data were collected (between 2000 and 2004), the EPA has eliminated "nearly all residential uses of organophosphate pesticides" from such things as lawn-care products and bug sprays "as well as some food uses to reduce risks to children." Critics, however, says there need to be further efforts: "The government made some big strides at reducing exposures, and then sort of got stuck," says Wiles.
Consider those towers of glistening grapes and piles of sweet bell peppers shipped to markets here from abroad, particularly during the winter. According to Benbrook, the USDA's pesticide data program "shows very clearly that there has not been a . . . reduction in the overall dietary risk in imported fruits and veggies, and in some cases the levels have actually gone up since 1996," including among said grapes and peppers. He blames this inconsistency on the fact that the EPA chose to limit how certain pesticides could be used in the U.S. farming rather than just set limits on the total allowable amount of chemical residues, which would have applied to both domestic and international growers. Benbrook adds that there are some indications in the USDA data that even imported produce labeled organic is not as clean as it should be.
As questions are raised on the role pesticides may play in ADHD and in other health problems, you'd be hard-pressed to find an expert who doesn't advise that people, especially pregnant women and small children, reduce their pesticide intake as much as possible.
The top recommendation? Eating an entirely organic diet, which has been shown to significantly lower people's exposure levels, says Hopkins pediatrician Goldman. If that's not financially reasonable, given the generally higher cost of organics, it also helps to carefully wash all your fruits and vegetables -- conventional, frozen, organic and otherwise -- in cold water. Benbrook, for one, recommends bypassing fancy produce washes for the equally effective combo of mild soap and a washcloth or brush. And then rinse thoroughly.
But be aware that you can't scrub away all the risks. "It's best to actually try to eat your way around pesticides . . . because most pesticides don't wash off, and seep into those blueberries or apple," says EWG's Wiles, who notes that the USDA data on pesticide levels is collected after produce has been washed, peeled and prepared the way you'd normally consume it.
As a result, he suggests eating organic when possible and otherwise relying on what his organization calls the "Clean 15." These are conventional fruits and vegetables with the lowest levels of chemicals: typically thick-skinned, heartier, easier-to-grow produce with peels that you throw away, such as onions, avocados, corn, pineapples and mangoes. Then there's the "Dirty Dozen," those foods with the highest average levels of pesticide residues. These are usually highly perishable fruits and vegetables with soft skins, such as celery, peaches, strawberries, apples, blueberries, nectarines and sweet bell peppers.
Can't face giving those things up? Another option is to buy local at a farmers market, says Bouchard. Surveys nationwide show that small farmers have fewer residues on their produce, she says, adding that buyers can ask vendors about which chemicals they used.
I did feel better this weekend when I noticed that many of the greens at our local farmers market, including a particularly beautiful batch of arugula, were labeled "no sprays." And when my son made a beeline for the huge containers of bright red strawberries, I discovered that the plants -- but not the berries -- had been sprayed with a single, general-use fungicide three weeks before being picked, and it would have dissipated significantly by market time.
I considered the relative risk, gritted my teeth at the price tag, and loaded a containerful into my bag.