Woah, boosting TNF levels does not sound like a good idea! TNF is an inflammatory cytokine which causes the inflammation in diseases like Crohn's, RA, psoriasis, etc. There are medications - Remicade, Humira - which specifically target TNF, hence why they are known as anti-TNFs or TNF-inhibitors.
It's not even a particularly good idea to try to boost the immune system. A strong immune system is not always a great thing:
en.wikipedia.org/wiki/Cytokine#DiseaseThat said, I do eat bananas regularly - sometimes 2 or 3 a day >_>. Luckily I prefer them on the underripe side without any brown spots though.
@pmedic - May be a texture thing? Some bananas are very mealy and I do not like those ones. Organic/fairtrade bananas are less likely to be mealy in my experience.