Scientific research on canine nutrition has given us a great understanding of dogs' nutritional requirements. Premium brands of dry dog food allow all breeds of dogs to get a nutritionally balanced diet with no deficiencies. The only nutritional problem seen in modern dogs, raised on appropriate brands of dry dog food, is obesity when fed too many calories. For the vast majority of dogs, all supplementation of vitamins and minerals is contraindicated. Dog foods are very well balanced in their mineral content, as well as their carbohydrate, fats, and protein ratios.
Occasional treats are fine.
Calcium phosphorus ratios are critical to dogs' skeletal well being. Most dog foods supply a ratio of 1 part of phosphorus to 1 part of calcium, which insures proper skeletal development and maintenance. When meat is added to the diet, this ratio can be severely altered as meats often have much more phosphorus than calcium. This can be very detrimental to rapidly growing puppies and adult dogs. Often the amounts suggested on the feeding charts on the bag are more than the relatively inactive urban house dog requires for optimal weight.