If the soil doesn't have the nutrients, then the plants that we eat do not have the nutrients. And to this the increasing amount of pesticides, toxins and pollution in our environment all of which require even greater amounts of nutrients in the body for detoxification purposes and a real problem is evident. There are two solutions. One is to eat totally natural and organic foods and the other is to use nutritional supplementation. Many of the nutritional supplements on the market today are in a form that cannot be used by the body.
Some vitamins are fractions of the whole vitamin complex instead of the whole complex.
Some are totally synthetic and can actually cause adverse reaction and body imbalances. You may have to research a bit to find a company that maintains a standard that is acceptable. They are out there however, and the value to your body is worth the small effort requried to find them and use them. Once again it comes back to basics. You can not build properly if you do not have the materials to build with.