My hair is healthy and it takes a long long time for me to get split ends. My hair generally grows slow though and since vitamins speed it up I assume I'm lacking in some things.
I did notice when I drank a lot of protein shakes during heavy workout times of year that I had more baby hair growth coming in. I guess I best start experimenting with that.
I feel like I get protein and my stats show I get a normal amount but maybe it's more bio available in the powder form. At least for my particular system.