They say Japan has a lower risk of cancer but their air quality is not good. Do you think it is their diet?

've actually studied the environment in Japan. They have 4 to 5 times less breast cancer, less prostate cancer, and even less brain cancer. But the trends in Japan are also increasing, especially in women in the city, when it comes to breast cancer. There are big dietary differences, and there are also big differences in exercise. People in Japan walk a lot more than we do. They also eat diets that contain a lot more vegetables and soy products, and they do not eat as much saturated fat and animal fat. In addition, until very recently in Japan, women could not even get birth control pills [so they were not exposed to estrogen from that type of medication].

There are lots of things that could explain the differences. In fact, the Japanese, if anything, have better air quality than we do, in part because they can't afford to drive. The toll roads from Tokyo to Kyoto, a trip of about 2 hours, literally costs about $90 for a car. So it's a very different world in terms of some of the pollution patterns they have.