There are so many places to start that defy what people think is true. Basically, all commercial pet food, even the stuff sold by vets, is garbage that is comparable to eating fast food 3 times a day. Actually, most garbage contains more nutritional value!
Even if you fed your pets what they need most - raw meat- it would need to be supplemented with similar vitamins and minerals as humans need.
Vitality Science has a number of products to get and keep your pets healthy.