Blueberries are high in antioxidants (tannins), which have been
found to reduce the risk of some cancers. Similarly, some of
the compounds found in blueberries (and cranberries) have a
significant impact in reducing the degradation of brain function.
Blackcurrants are very high in antioxidants, namely anthocyanins,
which give the fruits their dark colour. These are believed to help
protect your body against heart disease, and also ageing in general.