There is less agreement on whether it can also prevent cancer.
However, it is possible to prevent cancer and limit its effects in about 30% of cases.
Studies show they can play a role in preventing certain cancers and heart disease.
That's why it's important to talk to your doctor before you consider having any treatment to prevent breast cancer.
It included 48 recommendations for changes that different groups in society can make to help prevent cancer.
The use of supplements to prevent cancer is still being studied.
A classic example is that of genes which prevent cancer.
By accident, scientists found that such drugs might also prevent cancer.
But that approach cannot prevent breast cancer; the best it can do is catch the disease early.
The drug may also serve as a vaccine to prevent breast cancer.