Brisbane News | 8th Feb 2015
Most research comparing organic and conventional produce has focused on the nutrient content.
But, an extensive new study by Washington University researchers, has confirmed what is a logical conclusion to come to: that organic-eaters are exposed to far fewer pesticides.
The study, the largest of its kind, looked at the dietary exposure of more than 4400 people to pesticides used on food and found conventional produce eaters had double the levels compared with organic produce eaters.
“If you tell me what you typically eat, I can tell you how high your pesticide exposure is likely to be,” said Cynthia Curl, an assistant professor in Boise State University’s School of Allied Health Sciences and the lead author on this study.
“The study suggests that by eating organically grown versions of those foods highest in pesticide residues, we can make a measurable difference.”
Dr Ian Musgrave, senior lecturer in Pharmacology at the University of Adelaide, isn’t convinced the difference is meaningful.
Although those who ate conventional produce had double the amount of pesticides in their urine, it’s still well below the safety levels, Musgrave said.
“If you look at how much these people are being exposed to, it’s about 1000-fold less than the estimated safety levels of pesticide exposure,” he says or those who eat mostly or all organic produce.
This means that those who eat mostly or all conventional produce tested 500-fold below the estimated safety levels.
“If you eat mostly or only organic produce, you will excrete fewer pesticide metabolites but that the risk of having more pesticide metabolites in your body compared to the benefits of eating more fruit and vegetable is negligible.”
Adam Willson, chairman of the Organic Federation of Australia, disagrees that the risks are negligible.
“The testing of chemicals for human safety has been historically based on the LD50 test,” he says. “This is the Lethal Dose at which 50 per cent of rats die.
“It is an oversimplified toxicity test and completely misses the effects that chemicals have on humans and the environment.”
“There are over 100,000 synthetic chemicals in the environment, over 1500 used in agriculture worldwide.
“Agricultural chemicals are not tested for their cocktail effect prior to release.”
Musgrave says that most pesticides that we are exposed to are broken down “quite quickly” and notes that the safety levels “are considered to be our lifetime exposure”.
Despite this, the trend towards organic continues to grow.
The organic industry has grown year on year since 2008 at 15.4 per cent per annum and is now worth $1.72 billion, Willson says.
“Eighty per cent of consumers buy organic food because it is chemical free,” he says.
Cynthia Curl plans to further her findings by looking at the “neuro-cognitive outcomes” of pesticide exposure through food.
In the meantime, she is with Musgrave in her message that eating enough fruit and vegetables – conventional or organic – is the most important thing.
The organic versus conventional debate continues, but, she says: “The health benefits of eating fruit and vegetables are well established.”