Both vitamin and minerals have certain levels that are required for optimal health and either too much or too little generally can lead to health problems. For some nutrients the range where optimal health can be maintained is quite wide and the safety factor is quite high. Examples include Vitamin E, manganese and the B-vitamins. In contrast, other nutrients have a relatively narrow range and careful attention must be paid to these nutrient to ensure the pet gets enough for proper health, but not so much that signs of nutrient excess develop. Examples here include zinc, selenium and copper.
Cats can thrive on any diet , dry, canned or semi-moist, as long as it is complete and balanced.
Dry diets are generally less expensive to feed than canned diets. The crunchy texture of dry diets will also help keep the pet's teeth clean. However, even pets fed dry diets still need periodic cleaning and can benefit from the many treats and toys which help clean teeth. My cat really likes canned foods. Your cat will do fine on only canned food as long as it is complete and balanced.