Hi First, it has to be real apple cider vinegar. It has to be a true naturally ferment apple cider vinegar so generally it says "with mother" on the bottle. It means that your find remnants for the orginal apples that were ferments. The "mother" will look like a brown sludge that settles at the bottom and you often have brown bits in the vinegar when you use it.
As a naturally fermented food, it is very good for you like all tradtionally fermented foods. It can help with digestion and stabilze blood sugar when taken before a meal. It helps to prmote the maintenance of good bacteria in the gut and the colon and the phytonutrients, vitamins and are minerals that occur naturally in the apple are more bioavailable to the body becuase of the fermentation process. So from this perspective it is very good for you. You do have to be careful to to dilute istaking it by itself and it may cause discomfort to those who have an ulcer or thinnning mucus lining in their stomach. It is great to use in recipes and will give baked goods and food dishes longer shelflife by lowering the ph of these foods slightly to make them less inviting to bad bacteria and more synergistic to lactic acid bacteria (good bacteria). All vinergars make good natural preservatives.
There are various health claims made for which probably have some elements of truth but health issue are complicated and generally no one thing will work to fix a given health problem. So feel free to make it part of a well-balanced diet.
Response by Lorene Sauro B.A., R.H.N