Arthritis for Dogs Rapid Relief for your Dog from painful arthritis symptoms

Are there good dog foods for arthritis for a 13 year old dog?

She limps a lot because of her arthritis and sometimes i even rub her shoulders...its not like im pampering her its just that i want her to be able to climb our stairs. haha. So does anyone know any excellent dog foods for arthritis?...for dogs
English Springer Spaniel Type: Showdog NOT field dog