Hi Julia,
I’ve had these for years, though I have managed to reduce them somewhat. I’m not exactly sure which part of my diet or adaptations regime is responsible though. This is going to seem like a strange suggestion but, would you eat a banana every day for a week and see if it still persists ? (all other medical conditions permitting, that is!) It could be something as simple as electrolyte imbalance, so you’re best to try the simple treatment first.
Regards
Barbara
(UK)