Jury is out on that question. Blue swayers drink apple cider vinegar as a supplement because it is supposedly "alkalinizing" , but at the same time ACV has been proven to lower blood sugar levels signifigantly and I think the data supporting blood sugar and swaying is a heck of a lot stronger than the "acid/alkaline" stuff which has been largely debunked because you really CANNOT alter the pH of your blood from diet, and if the pH of your blood does change, you DIE. it may have an effect on CM pH tho, but there is no really strong evidence that it works real well.
Vinegar is allowed in dietary amounts on the LE Diet and I just personally do not believe that it could possibly "alkalinize" anything enough to matter. It really CAN lower blood sugar levels tho (proven).

