Photo: Jens Mortensen
Q: I use almonds, walnuts, pecans, and pine nuts in salads, granola, and snacks. Do nuts absorb pesticides in significant amounts? Is it important to buy organic nuts?
— Ann Chitty
A: It’s doubtful that nuts are a major source of pesticides in our diets for several reasons. For one thing, most pesticide residue would be removed once the nut is shelled. Sometimes shelled nuts are treated with fumigants—gases used primarily to kill insects—but there is no evidence that the chemicals used, such as methyl bromide, pose any threat to people when consumed. Also, nuts are very energy dense, so we tend to eat them in much smaller quantities than fruits or vegetables. The amount of pesticide residue a food can carry also depends on its surface area, and there is a lot more surface to a leaf of spinach than an almond or a walnut. If you’re still interested in minimizing your exposure to nut-related pesticides, look for organic nuts and nut butters.