Study: Organic diet reduces pesticides in body

It may seem obvious: When you eat an organic diet, you absorb fewer pesticides than when you eat conventional food.

What is startling in a new study that came out last week is just how fast and steep the difference can be.

According to the study, just six days of eating organic food can lower your body's level of evidence of the pesticide malathion by an extraordinary 95 percent, and an 83 percent drop in the level of evidence of clothianidin.

Studies making one outlandish claim or another occasionally cross this desk, and not all of them, shall we say, adhere to the strictest scientific rigor. This one, however, appears to be sound-but with plenty of caveats.

First, and perhaps most important, the sample size was ridiculously small. The scientists studied just four families, for a total of 16 people in all. It was short, too: They checked the concentration of pesticide metabolites over just 12 consecutive days-five days of their regular diet, six days of an organic diet and then one day of eating whatever they wanted.

The authors of the study also acknowledge other limitations to their work, including the possibility that the participants were exposed to pesticides outside of their homes. Also, some of the metabolites (that is a substance that is left over after something has metabolized) can be formed from sources that are not related to pesticides.

In addition, the study was funded by an advocacy organization called Friends of the Earth (interestingly, they are both Friend and FOE). The person who designed the study works for FOE, and the study has been released along with a specific political call for action.

Nevertheless, the study does appear to have some teeth to it. I say "appear," because I only understand perhaps three-quarters of it. It's written in Science, and I am not a fluent speaker.

The scientists studied four families from around the country (notably, they were from urban or suburban areas, where exposure to pesticides that are not on foods is presumably less than in agricultural regions). To determine how much pesticides the subjects had consumed, the scientists examined their urine every day during the trial. I'm sorry to say the families had to store it in their freezers until they sent it to the lab.

The lab found 14 pesticides and pesticide metabolites in the subjects. Thirteen of these were reduced significantly when the families switched to organic foods after just six days. Obviously, that is big news.

The folks at FOE contend that the pesticides that were found are all harmful to human health, or are at least potentially harmful. Some of their concerns push the evidence of harm to its rhetorical extreme, for the sake of their argument. You would expect that from an advocacy group.

But malathion, the pesticide to show the sharpest drop after the subjects began eating organic food, is sprayed in cities and areas across the country to control mosquitoes, with no evident health problems. It is also used to treat head lice.

Many farmers use pesticides because they control pests. The fewer pests, the better the yield. And it is only the current large yields that keep the Earth's population fed. If food were only grown organically, perhaps two-thirds more land would have to be used for crops to keep everyone fed in the future, according to one reckoning-and at a much higher cost.

On the one hand, you have clear (if tenuous) scientific evidence that eating organic food can lower our exposure to pesticides by a moderate to dramatic amount, depending on the pesticide. On the other hand, it would be virtually impossible to feed the entire world on organic foods.

What are you going to do?

Upcoming Events