Out of all the members of the berry family, blueberries are pretty much near the top of the table due to the fact they are full of antioxidants and flavonoids that can help prevent cell damage. The process of antioxidants is that they neutralize free radicals, atoms that contain an odd number of electrons and are highly unstable. These free radicals can cause the type of cell damage that can be a big factor in the onset of cancer.
There is a rich source of one particular type of flavonoid called anthocyanins in blueberries. These compounds are water soluble with pigments that are blue, violet and red depending on the pH level they have. Blueberries and apples both get their particular colour from anthocyanins.
Anthocyanins act as antioxidants and in plants and protect them from oxidative damage. This is also similar to the function they perform in human cells. Many studies do suggest that antioxidants such as anthocyanins can help prevent the free-radicals damage associated with cancer.
Further more than being just rich in anthocyanins, blueberries are a great course of vitamin C, which supports and boosts the immune system which in turn can help the body absorb iron and fight of infections. Another important factor for cancer patients is that vitamin C can also keep blood vessels firm, offering protection from bruising.