No kosher food isn't any healthier than other food. It just means the animal was butchered in a specific way, certain foods are not prepared/eaten togther, etc.. But it's the same food everyone else eats.
No, it's just the most kosher. Pork is less saturated than beef. Shellfish are lower in mercury than a lot of kosher fish. Non-kosher meat is lower in sodium than koshered meat. You don't keep kosher for health reasons, just for religious ones.