A common perception is that too much sugar is what makes kids "hyper." But what about eating fruits and vegetables? It may depend on how well you wash them.
A new study published in Pediatrics
suggests a link between commonly used pesticides and the development of ADHD
, or Attention Deficit Hyperactivity Disorder. Researchers tracked levels of the breakdown products of organophosphates, a common class of pesticides, in children's urine and found those with high levels were almost twice as likely to develop ADHD as those with undetectable levels.
Of note, the study population was not a specially selected group (such as farmworkers or children with known ADHD) but data from the general US population, culled from the National Health and Nutrition Examination Survey (2000-2004). This suggests potential harm from exposure to organophosphate pesticides at levels commonly found in our environment.
As quoted in Reuters
, a study author commented:
"There is growing concern that these pesticides may be related to ADHD," said Marc Weisskopf of the Harvard School of Public Health, who worked on the study. "What this paper specifically highlights is that this may be true even at low concentrations."
Organophosphates are known to be neurotoxins, or harmful to the nervous system. As such, it is biologically plausible that they could cause alterations leading to ADHD. They were originally developed for chemical warfare, with one example being Sarin. According to Reuters, there are about 40 organophosphate pesticides registered in the US, including malathion. Residues from these make their way into our food supply in the form of fresh fruits and vegetables.
The study sample included 1,139 children between 8 and 15 years. The authors conducted structured interviews the children's mothers or another caretaker, and found that 119, or about one in ten, met the criteria for ADHD, which is similar to the prevalence in the overall U.S. population.
For the most common breakdown product, called dimethyl triophosphate, the odds of ADHD almost doubled in kids with above-average levels compared to those without detectable levels. These numbers were adjusted for gender, age, race/ethnicity, poverty/income ratio, and fasting duration.
The study's lead author, Weisskopf, emphasized that these results are preliminary, and do not necessarily imply causation. More studies are needed before contemplating a ban on these pesticides. He recommended:
"A good washing of fruits and vegetables before one eats them would definitely help a lot."
That's sound, common-sense advice. You don't want to "throw out the baby with the bathwater;" the health benefits of eating fresh fruits and vegetables far outweigh any potential risks from bacterial or chemical contamination. But it pays to choose and prepare wisely. You should consider organic produce, when possible, and avoid organophosphate pesticides and insecticides at home. To see a comprehensive list of which fruits and vegetables are most important to choose organic, see the Environmental Working Group's list
. For all fresh produce, wash well before consuming, to reduce levels of both pesticides and bacteria.
-Begin with clean hands. Wash your hands for 20 seconds with warm water and soap before and after preparation.
-Cut away any damaged or bruised areas on fresh fruits and vegetables. Produce that looks rotten should be discarded.
-All produce should be thoroughly washed under running water just before eating. This includes produce grown conventionally or organically at home, or purchased from a grocery store or farmer's market. Even if you plan to peel the produce before eating, it is still important to wash it first.
-Washing fruits and vegetables with soap or detergent or using commercial produce washes is not recommended.
-Scrub firm produce, such as melons and cucumbers, with a clean produce brush.
-Drying produce with a clean cloth towel or paper towel may further reduce bacteria that may be present.
-You do not need to wash precut, bagged, or packaged produce items like lettuce that are labeled pre-washed and ready to eat.
© 2010 Linda Shiue
Maryse F. Bouchard, David C. Bellinger, Robert O. Wright and Marc G. Weisskopf. Attention-Deficit/Hyperactivity Disorder and Urinary Metabolites of Organophosphate Pesticides. Pediatrics, published online May 17, 2010.