Fish:

The top heart disease fighter. The theory is that fish oil lowers cholesterol and triglycerides, makes blood less sticky, and perhaps even decreases blood pressure.
Beyond the heart benefits it' s claimed that fish can alleviate rheumatoid arthritis and other auto immune disorders. It is also claimed that fish can reduce the size of tumours by keeping tumour cells in control.
Oily fish helps block breast cancer because omega-3 acid content boosts the immune system ability to respond to developing tumours.