So the good news is that eating peanut butter in youth can help keep away breast disease. The bad news is: You're already an adult. Too late. The good news is: So it's too late--who cares? It kept away *benign* breast disease only. No effect on malignant breast disease. Bad news: Having dense fibrocystic breasts can make you more likely to develop breast cancer. And it's hard to read fibrocystic breasts in the mammo machine. Those of us with dense breast/s harbor secrets..