What has helped me is to be super dilligent about taking care of my nails.
I keep them very short ( I play the piano), I use a cuticle cream to push back the cuticles gently, a buffer, and I always, always wear gloves when doing any housework where my hands will be getting wet or coming in contact with chemicals.
I also do not wear any polish anymore, and have seen a great improvement in my nails since eliminating that.
As far as diet deficiencies, I am not knowledgeable about that subject, so I'll keep my mouth shut.
