There is no definite prevention for breast cancer. There are some known risk factors that increase a person’s likelihood of developing a cancer. Most of these are out of your control – family history, breast density, having children, previously biopsied high risk growths. Some lifestyle factors however can be modified eg obesity, excessive alcohol, smoking, Hormone Replacement Therapy. Nonetheless, it is important to realize that ±75% of breast cancer patients had no risk factors at all. That is why, even if you have no family history, no known risk factors and consider yourself healthy, you are still at risk of breast cancer and should have annual screening.
There is suspicion that some diets predispose people to cancers especially those high in animal fat and processed food. However, there are no direct dietary links to breast cancer and a healthy diet does not exclude you from getting it. Being healthy though, certainly makes the various cancer treatments easier to tolerate and may provide better outcomes.