How the Body Defends Itself From the Risky Business of Living

Our cells take trillions of ‘hits’ each day from toxins both natural and man-made, but hardworking enzymes repair the damage

In the second of two articles about risk, the trillions of "hits" our DNA takes every day and the subsequent repairs are described. Much of the damage comes from natural causes, mostly the oxidizing byproducts of our own metabolism. Some comes from the natural pesticides that the plants we eat have evolved over the eons. For these reasons, Bruce Ames, a biochemist at the University of California at Berkeley, argues that the much smaller quantities of man-made pesticides we ingest with our food are trivial.

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