A new study has suggested that pesticide exposure during pregnancy may influence the health and development of children.  Researchers at the University of California, Berkeley's School of Public Health have found that prenatal exposure to organophosphates, a pesticide widely used on food crops, is related to lower intelligence scores at age 7.

The researchers measured an IQ score average variation of 7 points between those with mothers recording the highest exposure and those with the lowest exposure.  'Organophosphate' is a broad clasification of insecticides which are neurotoxic and kill insects through their action on the nerve enzyme acetylcholinesterase, an enzyme also present in human brain tissue.

Significant findings

These associations are substantial, especially when viewing this at a population-wide level," said study principal investigator Brenda Eskenazi, UC Berkeley professor of epidemiology and of maternal and child health. "That difference could mean, on average, more kids being shifted into the lower end of the spectrum of learning, and more kids needing special services in school."

"There are limitations to every study; we used metabolites to assess exposure, so we cannot isolate the exposure to a specific pesticide chemical, for instance," added Eskenazi. "But the way this and the New York studies were designed -- starting with pregnant women and then following their children -- is one of the strongest methods available to study how environmental factors affect children's health."

Limit exposure during critical stages of foetal brain development

It is important to note that markers of pesticide exposure during the pregnancy significantly correlated with childhood IQ.  However, exposure to pesticides after birth did not show the same association. This may suggest that the most important time to limit exposure to pesticides is during the critical stages of foetal brain development rather than in the child after birth.

This research is part of a trio of papers all to be published today – the other two studies were carried out at Mt Sinai Medical Centre and Columbia University.  All three papers show consistent results which serves to illustrate the significance of these findings.

According to the Centers for Disease Control, people are exposed to OP pesticides through eating foods from crops treated with these chemicals. Farm workers, gardeners, florists, pesticide applicators and manufacturers of these insecticides may have greater exposure than the general population.

Avoiding vegetables is not the answer

I'm concerned about people not eating right based on the results of this study," said Eskenazi. "Most people already are not getting enough fruits and vegetables in their diet, which is linked to serious health problems in the United States. People, especially those who are pregnant, need to eat a diet rich in fruits and vegetables."

My comments on this study:

There have been a few pieces of research lately claiming that 'organic is no better than non-organic' but many of these only look at the vitamin and mineral content and neglect to take into account the impact that pesticides have on human health.

As the head researcher pointed out, it is essential that pregnant mothers continue to eat fruit and vegetables during pregnancy.   The benefits of eating 5 a day will be far greater than the impact of pesticide exposure but if you can afford organic, that is great.  For those who can't stretch the budget, there are many things which can be done to reduce exposure:

• place vegetables in a sink filled with cold water and soak for a few minutes
• purchase a vegetable brush and give veggies a scrub before rinsing and putting away
• Although many nutrients are found in the skins, consider peeling non-organic vegetables and fruits
• consider vegetable washes which can be found in health food stores
• look at the Environmental Working Group's Shopper's Guide to Pesticides and consider going organic for those items which are shown to carry the most pesticides.  This includes celery, various berries, apples, peaches, peppers and spinach.  Also familiarise yourself with those vegetables shown to be low in pesticide and eat plenty of them!

Pesticides are not only neurotoxic.  They have been demonstrated through research to be 'oestrogenic', meaning they can stimulate hormone receptors in both men and women, disrupting hormone balance.  For this reason, where possible it makes sense for us all to aim to keep pesticide exposure to a minimum.

Other co-authors of the study are Jonathan Chevrier, Kim Harley, Katherine Kogut, Michelle Vedar, Celina Trujillo and Caroline Johnson at UC Berkeley's CERCH; Dana Boyd Barr at Emory University's Rollins School of Public Health; and Norma Morga at the Clinica de Salud del Valle de Salinas.

The National Institute of Environmental Health Sciences, the Environmental Protection Agency and the National Institute for Occupational Health and Safety helped fund this research.