I am an adult male (early 50's) who was "offically" diagnosed with adult ADD several years ago. I was prescribed ritalin to help "manage my illness". While the ritalin did seem to help keep me more focused, I did not want to be reliant on a drug for the rest of my life.
So a couple of years ago, my wife and I made some major changes in our lifestyle and diets...very similar to the changes you mentioned. It has made a HUGE difference. My ritalin intake now is almost non-existent. Along with the healthier organic diet, a daily dose of omega-3 fish oil has done wonders.