Trace elements are by definition small, but they are mighty. Magnesium and selenium help protect against heart disease. Copper keeps tissue elastic, and protects arteries from aneurysms. Chromium lowers risk of diabetes. Antioxidants slow aging. Boron guards against against arthritis. Zinc aids brain development and lowers risk of dyslexia.
In the past, we got sufficient trace elements from food. But our Western lifestyle doesn't adequately provide the trace elements we need for excellent health. It's a good idea to get as much of our trace elements from food as possible, but we need to be ready to take supplements as well.
"One would have to eat large amounts of food - and take large amounts of exercise to keep a balance. This of course is what primitive man would have done! As we age and become biochemically less efficient, these amounts all increase. One also needs efficient digestion to absorb these micronutrients."
Be aware that sugar, alcohol and caffeine will actually have a negative score on the trace element scale. In order for the body to metabolize them, sugar, alcohol and caffeine actually deplete some of the trace elements you've got, leaving you with a deficit.