Prostate cancer killed more than 37,000 men in the U.S. in 1999, and it gets ahold of men early and often. According to autopsy reports, about 25 percent of men in their 30s have latent prostate tumors, as do more than half of men in their 60s. However, says NBC News Chief Medical Correspondent Dr. Bob Arnot, research is beginning to show that this is a cancer that can be prevented or even reversed by dietary changes. The first key, he writes, is soy. America produces a lot but Americans eat very little. In countries in which soy is a dietary staple, men get prostate cancer at a fraction of the U.S. rate. (A second benefit of soy, says Arnot, is a high concentration of the amino acid tyrosine, which helps keep you alert.) Dr. Arnot lays out a dietary plan that includes lots of soy, along with antioxidant-rich fruits and vegetables. Not coincidentally, this is also a low-fat, heart-healthy diet. Dr. Arnot says that many men are simultaneously at risk for heart disease and prostate cancer; diets rich in saturated animal fats tend to trigger both conditions. Another benefit of Dr. Arnot's plan is that it prevents breast cancer, too, giving couples a powerful incentive to make the extreme dietary changes necessary to prevent these his-and-hers killers. And with or without the spousal incentive, Dr. Arnot says his experience with his own plan shows that men will lose weight, increase energy, and lower stress--a few valuable perks to take along on that longer, healthier life. --Lou Schuler