Generally better to eat healthy rather than take supplements, if at all possible. And extra-essential to discuss with the oncologist or chemo suite anything you are planning to take - there are some things you must not have while on chemo and others that can interact with your HT.
There is a cookbook on Amazon developed by scientists at Prostate Cancer Research UK - this explains the importance of a prostate healthy diet for young men (to reduce the risk of developing PCa later) and also gives some information about diet in men with advanced PCa. The scientists at PCRUK did not publish any advice or conclusions about diet for men with localised or successfully treated PCa.
Quite a lot of men on here take Pomi-T supplements but as above, essential to discuss with your medical people.
In terms of reducing chemo side effects, good idea to chop up and freeze fresh pineapple chunks and then suck the frozen cubes during the infusion - helps to minimise the side effects of mouth ulcers / sores and that awful metallic taste that so many patients are left with.