The breeder I buy from, says his live for 7-12 years when properly cared for.
He feeds them a self made beefheart mixture, the ingredients are:
Beef heart, plankton, shrimp, White Fish, spinach, Peas, Garlic, Gel Binder, krill hydrolysate, marine fish meal, refined marine fish oil, wheat germ, Spirulina, vitamins (choline chloride, ascorbic acid including stabilized vitamin C, vitamin E supplement, niacin, thiamin mononitrate, folic acid, calcium pantothenate, riboflavin, menadione sodium bisulfite complex, vitamin A acetate, pyridoxine hydrochloride, vitamin B12 supplement, vitamin D3 supplement, beta-carotene supplement, biotin), amino acids (dl-methionine, taurine, lysine), and trace elements (manganese sulfate, zinc sulfate, cobalt sulfate, ferrous sulfate, copper sulfate, sodium selenite).