by Don Kueck
Hutchinson News, Hutchinson, KS
Pesticides in our diets are 99.99 percent all natural according to an article I read recently in the “Proceedings of the National Academy of Science.”
A pesticide is any substance used to control a pest such as weeds, insects, fungi, etc. Most of us think of a product that is put on one of our food crops when we hear or read about dietary pesticides and their effect on our health. However, nature’s pesticides are an important subset of naturally occurring chemicals.
Plants produce toxins to protect themselves against fungi, insects and animal predators. Tens of thousands of these natural pesticides have been discovered and every species of plant analyzed contains its own set of one or two up to several dozen toxins. Besides the number, the levels of these toxins in plants can vary greatly depending on whether or not the plant has been “stressed” by an insect attack for example.
It’s been estimated that Americans eat about 1.5 grams of naturally occurring pesticides per person per day. This is about 10,000 times more than we eat of synthetic pesticide residues. This 1.5 grams is a rough estimate because everyone’s diet differs, but it is based on the pesticide content of some of our more commonly consumed foods. For instance, alfalfa sprouts on the salad bar contain 1.5% of canavanine, a naturally occurring pesticide and coffee contain 4% phenolics, another natural pesticide group of compounds.
Concentrations of these natural occurring pesticides are usually measured in parts per thousands or parts per million rather than parts per billion, the usual concentration of synthetic pesticide residues.
It’s been estimated that we eat about 5000 to 10,000 different natural pesticides and their break down products.
So what do these natural pesticides do to us? Surprisingly few plant toxins have been tested for their human cancer causing ability, one of the first risks we usually think of with pesticide consumption.
Among 1052 chemicals tested in one chronic cancer test, only 52 were naturally occurring plant pesticides and of theses, about one-half (27) tested out as carcinogenic or cancer causing.
These 27 were found in a wide array of foods from apples all the way through the alphabet to turnips and tomatoes. The list also includes broccoli. Maybe former President Bush read this report.
Looking at this list, it’s probable that almost every fruit and vegetable in the supermarket contains natural plant pesticides that cause cancer in rats. Rats are the normal test animal that we use to access risk to humans.
So why do we preach eating a diet rich in fruits and vegetables to lower cancer rates? As with all tests, much caution is necessary in interpreting the results. While fruits and vegetables do contain naturally occurring pesticides that are cancer causing in rats, they also are known to contain anti carcinogenic vitamins and antioxidants which counteract the cancer causing affect of the natural pesticides.
Bring us back to where we started, the Food and Drug Administration assayed food for 200 chemicals, including the most common synthetic pesticides residues, and found 105. The total per person daily intake of these 105 was .09 milligram vs. 1.5 gram a day intake of the natural pesticides, thus we end up with a diet that has 99.99 percent of our pesticide intake as natural.
What all of this means is that we have a long way to go in determining the risks in what we eat. It doesn’t hurt to be aware of the risks but let’s keep them in perspective, I doubt any one food or food group is going to kill or cure us. Moderation in all things is probably still the best policy, so pass me the beef and the bread, the beans and the broccoli too.
Reprint permission given by AgAir Update, P.O. Box 850, Perry, GA 31069 - an international agricultural aviation publication.
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