Thursday, March 12, 2009

What's in kale? Pesticides

(Photo: Kale 2008, early season in our garden last year)

Oh dear, not good, not good at all! The Environmental Working Group (EWG) has just updated The Pesticide Shopper's Guide, a wallet-size guide that lists the 12 fruits and vegetables with the highest level of pesticide contamination (i.e., the "dirty dozen") and the 15 with the least amount (i.e., "the Clean 15"). EWG has been compiling data and releasing this helpful information for 15 years, and this is the first year that I believe kale has shown up on the "dirty dozen" list.

One kale sample had 10 pesticides (these were rinsed samples). We grow ours organically with no pesticides, and it grows robustly with minimal to no pest damage. I actually recently read an article that showed organically fertilized kale had higher biomass production compared to the plants grown with synthetic fertilizer plus the butterfly larvae (i.e., pests) grew faster on the kale grown with synthetic fertilizers. Soil fertility management and pest responses: a comparison of organic and synthetic fertilization. J Econ Entomol. 2009 Feb;102(1):160-9.

What is particularly helpful about this EWG list is the guidance it gives shoppers who need to prioritize their food dollars (really, who doesn't?) to choose to spend money for organic produce that makes a potential health benefit. This new worrisome information about the pesticide levels on kale, while being one of the healthiest vegetables to really give you "bang for your buck" in terms of nutrients and phytochemicals, is reason to look for kale grown by organic farmers, preferably crops grown locally to really maximize the retention of those nutrients.

Sounds to me like organic kale is the way to grow for numerous reasons!

In addition to printing out the wallet guide to summary of clean and dirty fruits and vegetables, here is the link to the full list of the 47 fruits and vegetables that were tested.

This information will have me thinking twice before I eat kale as decoration on my plate unless I know the kale has been grown organically.

Where organic kale is much more than just decoration on my plate!

Diana Dyer, MS, RD


Anonymous said...

I grow happy kale organically too, but that does include a couple of applications of Bt through the season. I'm rather slow to apply it so I still get some holes - haven't been able to persuade cabbage loopers to just leave it alone. (Bt = Bacillus thuringensis, accepted as part of an organic regimen). Do you have any special tricks?

Diana Dyer said...

We don't do anything special except a good load of compost mixed in the soil during the spring. I'm not saying that we have no pests, but they are truly minimal. I only remember finding one good size worm on my kale when washing it in the sink.