There is multiple cause to depression, from traumatic event in our life, to biological factor as well a a brain chemical imbalance. 2/3 of our brain is made of fatty acids. Those are the major constituants of the membrane of the nervous system cells, cells that are the links in the communication between the nervous system cells, the brain, and the organ related in the body.
So what we eat is what nourrish those cells. If we eat saturated fat, fat that is solid at ambient temperature, like the one in animal fat, or butter, this will cause rigidity in the brain cells. But, is we eat polyinsaturated fat, fat that is fluid at ambient temperature, the brain cells will be more fluid, and the communication between the cells, more stable. One of the best example of plyinsaturated fat is omega-3 fatty acid.
There as been many study that shows the link between omega-3 fatty acid and depression. One of them deprive rat in laboratory of omega-3 fatty acid and the result showed a major behavioral change in mood and anxiety, as well as a decrease in the experience of pleasure. On the other hand, another study showed that a diet high in omega-3 fatty acid showed an increase of the good mood neurotransmettor. Many more study can be found on the subject.
Where to find omega-3 fatty-acids?
A diet high in fatty acid will help prevent depression, but if you suffer, from depression, it may be better to take fish oil as a supplement, to make sure you have enough omega-3 in your system.