Last November/ December I went on something called the Elimination Diet. It was three weeks generally with no smoking, caffeine, alchohol, eggs, diary, red meat, sugar or wheat and nothing processed. I ate mainly organic and I must tell you that I felt awesome! I slept better and had a fair amount of energy.
This prompted me to look into the nutrition section of The Anxiety and Phobia Workbook By Edmund J. Bourne, PH.D. and there seems to be some reference to how of these items affect anxiety.
For example: Caffeine & nicotine are known to aggravate anxiety. Salt, preserves and hormones in meat stress the body. Don't get me started about sugar ....
Anyway, just thought I would share my experience. The down side to the "diet" is sometimes it is difficult to stick to and it can be expensive eating all organic. I'm going to try it again soon to see how I feel this time around.