its ability to destroy cancer cells. At the same time, tobacco smoke can damage cell DNA, increasing the chance for cancer cells to form and flourish in the first place.6 To test the power of dietary interventions to prevent DNA damage, scientists often study chronic smokers. Researchers rounded up a group of longtime smokers and asked them to consume twenty-five times more broccoli than the average American—in other words, a single stalk a day. Compared to broccoli-avoiding smokers, the broccoli-eating smokers suffered 41 percent fewer DNA mutations in their bloodstream over ten
