Is yours able to do some digging around or make suggestions for a good supplement, even if it is RX?
Once our nutritionist found the right thing, she wrote up the RX. She works at a Children's Hospital and has the power to write RX's, but I'm not sure if all nutritionists do. If not, maybe all she would have to do is send a reccomendation to your Dr, and he/she will write it for you.
Or maybe you've already been that route, so just ignore me.
.... I'll just be busy working on my 101 ways to be creative with avocados recipe collection!