Currently, the American Public Health Association is holding its 137th Annual Meeting and Exposition in Philadelphia, PA.  A pilot randomized control trial was presented on November 9, 2009, in poster format to show the connection between diet and mood, and more specifically, the benefits of a vegetarian diet on mood.

Arizona State University researchers studied 39 participants all who were omnivores (eating both meat and plants). They divided them into into three groups: the control group made no changes to diet, the fish group at three to four servings of fish per week and eliminated all other meat, and the vegetarian group consumed no meat and no eggs.

Researchers found that while the control and the fish groups showed no significant mood changes, the vegetarian group experienced both less tension and less confusion.

Source:  Beezhold BL, Johnston CS, Daigle DR. Restriction of flesh foods in omnivores improves mood: a pilot randomized controlled trial. Poster presented at: American Public Health Association's 137th Annual Meeting and Exposition; November 9, 2009: Philadelphia, PA.