I tried using apple cider vinegar on my hair for about 6 months last year as it helped my scalp (I suffer a bit from seborrheic dermatitis - dry and oily skin).
I thought by reducing my seborrheic dermatitis I might be able to regrow some hair I lost. It didn't regrow any hair and only marginally made my scalp better. I didn't experience any more shedding than normal while using it. I'd say its worth trying though - its natural and cheap and it might work better for you than it did for me. If you're going to try it make sure you get the organic stuff with "the mother". I diluted it too. I'm back to using nizoral shampoo to control my seborrheic dermatitis, which seems to be a bit more effective than apple cider vinegar. I guess neither of these options are the silver bullet for my scalp, but they help.
Nautral solutions always interest me. I recently watched a documentary called "Knives over forks" (only released last year) and was amazed how they were able to turn cancer growth on and off through diet... I think i might give the plant based diet a shot for my health, even though its probably not best for my hair. I'm confident there will be a solution for hair loss within the next 5 years.
Anway, good luck with it