I was at the market picking out some grapes when a large woman ran up to me and grabbed my arm. “Don’t buy those!” She looked alarmed. “They’re not organic!”

Thankfully, I’m rarely accosted in the produce department , but I frequently hear the same lecture from many of my friends. Don’t take man-made drugs. Don’t use artificial sweeteners. Don’t eat food that isn’t organic. You’re poisoning yourself. Natural is safe. Everything else isn’t.

I should point out that I have no desire to poison myself with dangerous chemicals, but our concern about the difference between “natural” and “man-made” chemicals is irrelevant. Both laboratories and nature produce those that are safe and others that are not-so-safe. Arsenic is natural. Vitamin C can be replicated in a laboratory.

One of the reasons I’ve always grown veggies is to keep them as free of pesticides as possible. But now I find that growing pesticide-free produce is pretty much impossible.

A pesticide can be defined as any substance used for destroying insects or other organisms harmful to cultivated plants or to animals. And long before farmers started spraying synthetic pesticides on their crops, Mother Nature beat them to it.

Here’s one example. We all know that tobacco contains nicotine. It’s a natural pesticide, produced by the plant to deter or kill insects feeding on the leaves. (Nicotine in pollen serves a different purpose—see a fascinating article here.) Anyone concerned about their health will avoid tobacco, but that isn’t the only crop that contains nicotine. Nightshades, including tomatoes, peppers, eggplant, and potatoes also contain nicotine, as does cauliflower. It’s even found in green and black teas, normally considered to be extra-healthy.

It turns out, the plants we typically eat are brimming with natural pesticides. Organic cabbage, for example, contains 49 of them! Pesticides are found in everything from grains, legumes, and kale to herbs and spices. The very chemicals that give these seasonings their flavor also protect them from pests.

Some of these chemicals only affect specific insects, but others are quite dangerous to humans. According to a Colorado State Extension article,

Rotenone is produced from the roots of two tropical members of the bean plant family. It has been used as a crop insecticide since the mid-1800’s to control leaf eating caterpillars, and it often is recommended [as an organic pesticide] for flea beetle control on early season vegetables. It is six times more toxic than carbaryl, (sevin), a synthetic product, also effective for caterpillar and flea beetle control.

Many of us avoid chemically-treated food because we’re concerned about their ability to cause cancer. That’s a valid concern—about half of synthetic pesticides are carcinogens. But what about these naturally occurring, plant-made pesticides? Of the few that have been tested, half of them are carcinogens as well!

We can’t very well stop eating food, nor should we panic. There’s one aspect of this that I haven’t mentioned yet. When it comes to chemicals, natural or man-made, there are two considerations: what, and how much. And it’s how much that makes the difference.

Many substances are perfectly safe at small doses, but lethal in larger amounts. Thankfully, while the plants we eat do contain dangerous chemicals, they don’t contain too much of them. (If they did, we wouldn’t eat them, would we?) Scientists measure most of these natural pesticides in parts per million, which isn’t normally enough to hurt us.

How does this quantity compare to permitted residues of synthesized pesticides? Federal guidelines governing their use measure residues in parts per billion, an order of magnitude smaller!

Or to put it another way—according to a 1990 paper on dietary pesticides, the authors estimate that “we eat an estimated 1.5 grams of natural pesticides a day, ‘which is about 10,000 times more’ than the amount of synthetic pesticide residues we consume.”*

Kinda puts things into perspective, doesn’t it?
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* I highly recommend the article this quote came from—see https://www.geneticliteracyproject.org/2015/03/20/myth-busting-are-synthetic-pesticides-used-with-some-gmos-more-dangerous-than-natural-ones/