Plants and Pesticides

The voracious appetites of pests put plants under constant stress. They have to fight just to stay alive. And fight they do. Far from being passive victims, plants have evolved potent defenses: chemical compounds that serve as toxins, signal an escalating attack, and solicit help from unlikely allies. ¹ In some cases plants lure attackers into a carefully set trap. An example: plants in the Brassicaceae family (including broccoli, cabbage and mustard) store seemingly harmless compounds known as glucosinates in cellular compartments next to stores of enzymes called myrosinase. The two reserves are separated only by a thin cell wall. When an unsuspecting herbivore chews through this wall, the myrosinase enzymes mix with the glucosinates, catalyzing chemical reactions that engulf the attacker in a toxic cloud. It's these reactions that give Brassicaceae species their characteristic bitter flavor and antioxidant properties.

Biological warfare was invented and perfected by Mother Nature

Organic tomatoes have a slightly higher polyphenol content than those grown by conventional means. Without the application of synthetic pesticides and fertilizers, tomato plants are more stressed and produce more polyphenols so they produce the chemicals to help them survive stressful conditions such as a lack of nutrients in the soil or attack by insects and fungi. However, for organic produce enthusiasts, Dr. Joe Schwarcz points out that in the context of an overall diet, the small differences between the polyphenol content of organic and conventionally grown produce is irrelevant. ² There are probably hundreds of thousands of pesticides in the natural environment. As it turns out, biological warfare was invented and perfected by Mother Nature. For example, some bacteria and fungi produce antibiotics to kill other microbes. We don't call these antibiotics 'pesticides' but that's exactly what they are. To a bacterial cell, a microbe of a different species is often nothing more than a competitive pest that should die. So, it produces chemicals with the intention of killing it. That's a pesticide. ³ Plants do the same thing. From a plant's point of view, many insects are nothing more than dangerous, leaf-eating parasites that should die. So plants produce chemicals to keep those obnoxious, six-legged vegetarians away. And guess what? When we eat plants, we're eating those pesticides too. A paper co-authored by Bruce Ames and colleagues from the University of California, Berkeley found that 99.99% of the pesticides we consume in our diet are produced by the plants themselves. Given the popularity of organic food and the unscientific mythology underlying it, his findings are more relevant now than ever. ⁴ Dr. Ames estimates that “Americans eat about 1.5 grams of natural pesticides per person per day, which is about 10,000 times more than they eat of synthetic pesticide residues.” He adds it is probable that almost every fruit and vegetable in the supermarket contains natural plant pesticides that are rodent carcinogens. The levels of these are commonly thousands of times higher than the levels of synthetic pesticides.

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Another issue regarding pesticides is the so-called pesticide free organic foods

The EPA's risk estimates overstate pesticide exposure by as much as 99,000 to 463,000 times actual exposure, As a result, standards are actually tens of thousands—maybe hundreds of thousands—times more stringent than necessary to protect public health. ⁵ Another issue regarding pesticides is the so-called pesticide free organic foods. People should be aware that just because it is organic doesn't mean it is without pesticide. Steve Savage points out, “Many consumers believe that by buying organic they are eliminating exposure to pesticide residues. This erroneous concept is often encouraged by some of those who market organic products or those who advocate for organic. There is a long list (1700 products) of the materials allowed on organic products published by the Organic Material Review Institute (OMRI). The pesticides on this list are definitely real pesticides (they kill pests) and so they have to be registered for use by the EPA like any other pesticide.” ⁶ Here are some natural poisons that organic farmers are allowed to use:

• Sulfur, which Cornell University researchers concluded was the most environmentally harmful substance widely used in farming.
• Pyrethrum, a mixture of nerve toxins squeezed from African-chrysanthemums deemed by the EPA to be a 'likely human carcinogen.'
• Rotenone, a neurotoxin that causes symptoms similar to Parkinson's disease.

However, the important thing to note, is that pesticide levels in the food we eat are at levels far below those that would pose any health concern. ⁷ Want to eliminate all pesticides from your diet? Stop eating!

References

1. Mike Newland, “When plants go to war,” Nautilus, December 31, 2015
2. Joe Schwarcz, Is That a Fact?, (Toronto, Canada, ECW Press, 2014)d
3. Alex Berezow, “99.99% of pesticides we eat are produced by plants themselves,” acsh.org, June 13, 2017
4. Bruce Ames et al., “Dietary pesticides (99.99%) all natural)”, PNAS 87:7777-81, October 1990
5. Angela Logomasini, “The dangerous demonization of our food,” Competitive Enterprise Institute, August 4, 2012
6. Steve Savage, “An unlikely pair: heavy metals and organic produce,” redgreenandblue.org, September 27, 2010
7. Carl. K. Winter, “Chronic dietary exposure to pesticide residues in the United States.” International Journal of Food Communication, 2:11, July 10, 2015