I'm a doctor. I'm not aware of any classic pathology that involves cerebral vasculature and vitamin B. There are some cerebral vasculitides that might initially be diagnosed as vitamin B deficiency, and vice versa.
Quora user Lazlo B Tamas would be a good person to ask, though coincidentally he has already gave his answer to the question itself and didn't address this answer.
What specific symptoms would you suppose would be associated to having both?
For years I've suffered from headaches and I feel the cause is almost always a lack of oxygen (I suppose) to my brain. I've realized I definitely suffer from shallow breathing and over the past few years I've learned to breathe deeper. It has definitely helped a lot, though I always wonder if there's something else.
Quora user Lazlo B Tamas would be a good person to ask, though coincidentally he has already gave his answer to the question itself and didn't address this answer.