The way I see it is carp have survived for I'm guessing 1000's of years without anglers feeding them ,by eating what ever they can , I doubt a fish who never see's bait would look at food and think about what vitamins it contains . It's just going to eat it. Clearly the only way they get big , as fast as they do is by eating good quality bait but I'm not convinced you need HNV to catch them . Wanting to give them a decent balanced bait is a totally different thing and of course can only be a good thing .