Gut health has a lot to do with quality of boner. When I changed my diet to a lower-carb diet I felt my erections were harder. Other big components in boner quality are: joy, a sense of curiosity, actively seeking out new things, and smiling.
I I'll say what we mostly already realize but need to live by.. Cardio/blood flow and mostly all things good come with exercise. (more of a publicly posted note to self)
