The time change means shorter days, cooler weather, and, for some, seasonal depression. Seasonal affective disorder (SAD) is thought to be from changes in brain chemicals triggered by less light and more darkness, and is a real issue affecting around 20 percent of people usually in late fall and ending in spring. Light therapy and exercise, as well as prescription medication, are all used to combat SAD, and some diet choices may have subtle effects on depression and mood as well. While not a replacement for other therapies, these seven diet suggestions may give you a little mood boost during the winter.