Adsederq...
Ask and ye shall receive. First, we need to define "need". If you define "need" as the amount of vitamins and minerals you need to obtain RDA amounts, then yes...it's possible to obtain those levels IF you eat right. However, most people do not eat right. Plus, the RDA levels are the MINIMUM amount one needs to get to prevent classic diseases such as scurvy and rickets. The RDA of Vitamin C is 60mg, or one orange. That will prevent scurvy.
However, if you define "need" as the amount you need to obtain optimum levels, then it becomes fairly difficult to get those amounts through the food you eat. For example, an optimum amt of Vitamin C is 1000-2000mg/day. Vitamin E is 400IU/day. You would need to eat about 33lbs of spinach/day to get this amount. Part of the problem stems from minerals being leached from the soil, modern farming techniques, and food processing.