 The best way to study DNA repair is to study smokers, because they need a lot of it. A group of smokers, for a total of 10 days, were asked to eat six times more broccoli than the average American consumes— in other words, a single stalk. Compared to smokers not eating broccoli, those who did suffered about 30% less DNA damage over those 10 days. Maybe it was because the broccoli boosted the detoxifying enzymes in their livers, and so the carcinogens never made it to their DNA? Well, they tested for that. They actually took some DNA out of their bodies, put it in a test tube, and exposed it to a known DNA-damaging chemical. The DNA of broccoli eaters suffered significantly less damage. The DNA of those eating broccoli appears intrinsically more resistant at a subcellular level. In conclusion, in the present study, the intake of broccoli seems protective, as far as DNA damage is concerned, and smokers who are exposed to oxidative stress.