There hasn't been a discussion on diet for a while on this site and the newly diagosed may benefit from some of our thoughts and experiences.
When I knew that I couldn't have treatment for a few months and any HT would nulify the test I was scheduled for, I was concerned that my PC would spread during this time. I had a psa of 40 that was still rising. I asked my doctor what I could do to slow down the PC during my waiting period: he said go on a vegan diet. I said are you kidding? he said he was dead serious.
He said that if anyone told him 10 years ago that diet had any effect on PC he would have dismissed them outright, but after seeing many patients that were on "weird diets" and their PC had dramatically slowed he couldn't ignore the influence of diet anymore. He suggested a couple of books and said make up your own mind. So I started to do some research.
I don't think there is a magic pill or diet that can cure PC as some claim, but I do think there is substantial evidence that diet and supplements can slow the growth, and prevent some types of PC and reoccurrances. My PSA went from 40 to 30 and stayed level for 4 months with nothing changed but diet and supplements. It had never gone down in 10 years except once when I took proscar then immediately started to rise again.
I eliminated all red meat and dairy and try to keep my intake of animal protien, fish and chicken, to about 5%. Lost 10 lbs and feel better than I did 20 years ago; have ton's more energy. All my heart related numbers such as HDL, LDL, tryglycrides, and glucose have all gone from high to low range.
I take normal levels of Vitimine C, and D, selenium, calcium citrate, pomegranate extract, green tea extract, and lycopene extract.
I tell my friends I'm a jack vegan, I don't think a small amout of meat or dairy will harm you and might have some meat occasionally in the future. For a guy that lived on burgers and carne asada burritios the diet change was an adjustment; it's hard to find fast foods that are healthy. I needed the shock of having PC to change my habits.
I'm convinced that my previous diet probably played a role in my getting PC and definately had a role in my high heart related numbers. My doc said that most of his patients die from heart attacks not from PC and he specializes in advanced PC cases. So at the very least I'm covering the heart angle.