It is atkins, not adkins. It is also not a "fad" diet. The low carb diet has been out for atleast fifty years, it is just now called "atkins diet" because that is the name of the guy who wrote one of many books about it. His got popular though, unlike the other ones. Yes, you do need to take a multivitamin as with any diet.
Now if you stayed in the first phase of the atkins diet, it would definately not be balanced or safe for that matter, but you slowly add carbs to your diet until you get to the amount that your body can handle. So, yes, the beginning of the diet is definately not balanced and it is not a long term plan, but if you continue to progress within it, it is healthy and had many long term benefits.