Just because you have kids doesn't make you a nutrition specialist (talking to military mummy). *rolls eyes*
Fresh fruits and veggies are always better. You have to think too, they have to HEAT these V8 juices to make sure it kills bacteria (which is bullshit...but whatever). But where is the logic in, "it only kills bacteria"? When you heat stuff up, you denature almost everything. That's why people say "cold press" is better. So just because the nutrition label says it contains stuff, it doesn't mean your body can actually utilize it.
And honestly, I wouldn't contact your medical doctor. Yes, you heard right. If anything, find a nutrition specialist or a chiropractor. MD's take 3 credit hours of nutrition, yet people still think they know everything? It's ridiculous. Yet, nutrition specialist...SPECIALIZE in it. Chiropractor's also love to take seminars that all the nutrition specialists take so they are also very wise when it comes to health (most of the newer chiropractors though; most older ones are ignorant to that part of the health field).