Are "superfoods" and supplements (fish oil, vitamins?) beneficial if you already have a balanced diet?

Your balenced diet is composed of grains cerels green veg are produced from lands which are minerals depleted due to long time using lands using fertilizers chemicals and minerals pectsides.The dairy milk products meats eggs etc comesfrom antiobiotic hormones fed animals. So consuming such products not only becomes less nutritious forfor our body the minerals made and stored in our body becomes depleted in passage of time making our body?immune system weak causung many diseases to form inside the body. So a suppliment of a multivitamin comes to rescue.Addition of super foods and fish oil are extra benefits.