I have been doing some research into this area. Firstly, my coeliac diagnosis in 2014 lead to a huge change in diet - no more beer, no more bread, and out went most processed foods due to gluten contents.
Then 2 members of my local community PCa support group reported good results from following an Aussie wellness 'guru' Kristine Mathieson. Both have been able to reduce PSA using her protocol. Her protocol is pretty intensive however, its a full-time job in itself so I didn't immediately jump onto the band wagon.
Due to continued rise in PSA after prostatectomy and IMRT I gave up all booze (mainly red wine as beer was already off the menu) and red meat in mid-2016. I went fully vegetarian in Dec 2016. Finally, at end of March in 2017, I decided to quite work and give the Kristine Mathieson diet a full-on go. With the added proviso that I am now fully vegan, even though KM says that its OK to have poached eggs, yoghurt and soft cheese.
The good news - after 6 weeks on the diet I felt good and i could see some very positive health benefits.
cholesterol reduced from 5.5 to 3.8
triglycerides reduced from 1.3 to 0.8
blood pressure now sitting at 110/70.
However the bad news - PSA went up from 2.5 to 7.5. In only 6 weeks.
At this point (May 2017) I started ADT, and decided to stick with the program because there was ample evidence of benefits to general health, notwithstanding the lack of impact on PSA. And after 5 months of ADT I can still see the benefits of this diet. I have lost 20kg since starting the diet (from 90kg to 70kg). I have plenty of energy and play competition tennis twice a week, lift weights every day and walk for 4 to 6km daily. The only side effect of ADT is no libido - but then again, I had pretty bad ED after surgery and IMRT, viagra wasn't working and injections were losing effectiveness so I can't really blame ADT.
I was hoping that the diet would assist the Zoladex in knocking off some PCa cells but in first 3 months of ADT my PSA had only a very slight drop from 7.5 to 2.0. This is way less than many men achieve from ADT alone, so its's very clear that the diet has not made any difference to PSA levels.
All the claims about diet (eg Chris beat Cancer) are anecdotal and are highly suspect. My story is anecdotal as well so it must also be considered suspect as well . It's just one man's experience but in summary, my views on plant-based diets.
1. I would recommend this diet to anyone. Dealing with cancer is tough, and you need to be in the best shape possible to cope with side effects of the disease, and the treatment. I believe that the diet is certainly a positive benefit in this regard.
2. The diet has actually had zero impact on my PSA levels and by implication, has not killed any cancer cells. In fact it hasn't even slowed down the PSADT (1 month prior to ADT).
Please let me know if you have tried dietary approaches and what success you have had.
BTW - you never stop missing beer and meat. If the cancer doesn't kill me first, I may well die from lack of a good BBQ.