Recent research indicates that depression is an allergic reaction to inflammation.

Inflammation is the body’s natural response to infection, injury or foreign invasion, and when inflammation is triggered, the body produces many chemicals, such as cytokines. Tim de Chant of NOVA writes: “Inflammation is our immune system’s natural response to injuries, infections, or foreign compounds. When triggered, the body pumps various cells and proteins to the site through the blood stream, including cytokines, a class of proteins that facilitate intercellular communication. It also happens that people suffering from depression are loaded with cytokines.”

Chronic inflammation is caused by obesity, high sugar diets, high quantities of trans fats, unhealthy diets in general, and other causes. [The standard American diet promotes inflammation due to an abundance of inflammatory omega 6 fatty acids and a lack of omega 3s.

http://www.realfarmacy.com/cause-depression/